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psi-mi.obo
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format-version: 1.2
date: 15:04:2021 22:57
saved-by: pporras
auto-generated-by: OBO-Edit 2.3.1
subsetdef: Drugable "Drugable Genome Project"
subsetdef: PSI-MI_slim "Subset of PSI-MI"
subsetdef: PSI-MOD_slim "subset of protein modifications"
synonymtypedef: DeltaMass-label "Label from MS DeltaMass" EXACT
synonymtypedef: PSI-MI-alternate "Alternate label curated by PSI-MI" EXACT {http://purl.obolibrary.org/obo/mi#PSI-MI-alternate=""}
synonymtypedef: PSI-MI-short "Unique short label curated by PSI-MI" EXACT
synonymtypedef: PSI-MOD-alternate "Alternate label curated by PSI-MOD" EXACT
synonymtypedef: PSI-MOD-short "Unique short label curated by PSI-MOD" EXACT
synonymtypedef: PSI-MS-label "Agreed label from MS community" RELATED
synonymtypedef: RESID-alternate "Alternate name from RESID" EXACT
synonymtypedef: RESID-misnomer "Misnomer label from RESID" RELATED
synonymtypedef: RESID-name "Name from RESID" EXACT
synonymtypedef: RESID-systematic "Systematic name from RESID" EXACT
synonymtypedef: UniMod-alternate "Alternate name from UniMod" RELATED
synonymtypedef: UniMod-description "Description (full_name) from UniMod" RELATED
synonymtypedef: UniMod-interim "Interim label from UniMod" RELATED
synonymtypedef: UniMod-label "Label (title) from UniMod" RELATED
synonymtypedef: UniProt-feature "Protein feature description from UniProtKB" EXACT
default-namespace: PSI-MI
remark: coverage: This file collect controlled vocabularies describing different aspects of molecular interactions.
remark: CVversion: 2.5.5
remark: Each of the top level terms in this file is the root term of an independent controlled vocabulary
remark: formalized in a mapping file available at http://www.psidev.info/files/validator/xml/MI-CVMapping.xml.
remark: mapping an element of the PSI Molecular Interaction XML schema.
remark: Notes:
remark: psi-mi.lastac. It MUST be updated when this file is updated.
remark: publisher: This file is published by the PSI MI working group see http://psidev.info/MI
remark: short labels are reported as PSI-MI-short synonyms that are created when a term is more than 20 characteres long.
remark: The correct use of these vocabularies in the PSI Molecular Interaction XML schema is
remark: The last accession number used in this file is stored in a separate file,
remark: The maintenance of this file is ensured by Pablo Porras Millán pporras@ebi.ac.uk and Sandra Orchard orchard@ebi.ac.uk
remark: The PSI MI schema defines short labels for controlled vocabulary terms
ontology: mi
owl-axioms: Prefix(owl:=<http://www.w3.org/2002/07/owl#>)\nPrefix(rdf:=<http://www.w3.org/1999/02/22-rdf-syntax-ns#>)\nPrefix(xml:=<http://www.w3.org/XML/1998/namespace>)\nPrefix(xsd:=<http://www.w3.org/2001/XMLSchema#>)\nPrefix(rdfs:=<http://www.w3.org/2000/01/rdf-schema#>)\n\n\nOntology(\nDeclaration(AnnotationProperty(<http://purl.obolibrary.org/obo/IAO_0000115>))\nDeclaration(AnnotationProperty(<http://www.geneontology.org/formats/oboInOwl#SubsetProperty>))\nDeclaration(AnnotationProperty(<http://www.geneontology.org/formats/oboInOwl#created_by>))\nDeclaration(AnnotationProperty(<http://www.geneontology.org/formats/oboInOwl#creation_date>))\nDeclaration(AnnotationProperty(<http://www.geneontology.org/formats/oboInOwl#hasDbXref>))\nDeclaration(AnnotationProperty(<http://www.geneontology.org/formats/oboInOwl#hasOBONamespace>))\nDeclaration(AnnotationProperty(<http://www.geneontology.org/formats/oboInOwl#id>))\nDeclaration(AnnotationProperty(<http://www.geneontology.org/formats/oboInOwl#inSubset>))\n\n\nAnnotationAssertion(Annotation(<http://www.geneontology.org/formats/oboInOwl#hasDbXref> \"PMID:15833125\") <http://purl.obolibrary.org/obo/IAO_0000115> <http://purl.obolibrary.org/obo/MI_1285> \"OBSOLETE: An effect in which individual perturbations of two different genes result in opposite mutant phenotypes (traits measured on the same scale but each on opposing sides relative to the wild type phenotype), and the resulting phenotype of their combination is equal to that of only one of the perturbations. With respect to any single quantifiable phenotype, this may be expressed as an inequality as:\n(a < wt < b) AND (ab = a OR ab = b) \nwhere 'a' and 'b' are the observed phenotype values of the individual perturbations, 'ab' is the observed phenotype value of the double perturbation, and 'wt' is the wild type phenotype value.\")\nAnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#created_by> <http://purl.obolibrary.org/obo/MI_1285> \"orchard\")\nAnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#creation_date> <http://purl.obolibrary.org/obo/MI_1285> \"2013-06-05T20:51:51Z\")\nAnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#hasOBONamespace> <http://purl.obolibrary.org/obo/MI_1285> \"PSI-MI\")\nAnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#id> <http://purl.obolibrary.org/obo/MI_1285> \"MI:1285\")\nAnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#inSubset> <http://purl.obolibrary.org/obo/MI_1285> <http://purl.obolibrary.org/obo/mi#PSI-MI_slim>)\nAnnotationAssertion(rdfs:comment <http://purl.obolibrary.org/obo/MI_1285> \"Term replaced by\nhttp://purl.obolibrary.org/obo/MI_1276\")\nAnnotationAssertion(rdfs:label <http://purl.obolibrary.org/obo/MI_1285> \"obsolete opposing epistasis\")\nAnnotationAssertion(Annotation(<http://www.geneontology.org/formats/oboInOwl#SubsetProperty> <http://purl.obolibrary.org/obo/mi#PSI-MI_slim>) <http://www.geneontology.org/formats/oboInOwl#inSubset> <http://purl.obolibrary.org/obo/MI_2425> \"\")\n)
[Term]
id: MI:0000
name: molecular interaction
def: "Controlled vocabularies originally created for protein protein interactions, extended to other molecules interactions." [PMID:14755292]
subset: Drugable
subset: PSI-MI_slim
synonym: "mi" EXACT PSI-MI-short []
[Term]
id: MI:0001
name: interaction detection method
def: "Method to determine the interaction." [PMID:14755292]
subset: Drugable
subset: PSI-MI_slim
synonym: "interaction detect" EXACT PSI-MI-short []
is_a: MI:0000 ! molecular interaction
[Term]
id: MI:0002
name: participant identification method
def: "Method to determine the molecules involved in the interaction." [PMID:14755292]
subset: PSI-MI_slim
synonym: "participant detection" EXACT PSI-MI-alternate []
synonym: "participant ident" EXACT PSI-MI-short []
is_a: MI:0000 ! molecular interaction
[Term]
id: MI:0003
name: feature detection method
def: "Method to determine the features of the proteins involved in the interaction." [PMID:14755292]
subset: PSI-MI_slim
synonym: "feature detection" EXACT PSI-MI-short []
is_a: MI:0000 ! molecular interaction
[Term]
id: MI:0004
name: affinity chromatography technology
def: "This class of approaches is characterised by the use of affinity resins as tools to purify molecule of interest (baits) and their binding partners. The baits can be captured by a variety of high affinity ligands linked to a resin - for example, antibodies specific for the bait itself, antibodies for specific tags engineered to be expressed as part of the bait or other high affinity binders such as glutathione resins for GST fusion proteins, metal resins for histidine-tagged proteins." [PMID:7708014]
subset: PSI-MI_slim
synonym: "affinity chrom" EXACT PSI-MI-short []
synonym: "Affinity purification" EXACT PSI-MI-alternate []
is_a: MI:0091 ! chromatography technology
is_a: MI:0400 ! affinity technology
[Term]
id: MI:0005
name: alanine scanning
def: "This approach is used to identify the residues that are involved in an interaction. Several variants of the native protein are prepared by sequentially mutating each residue of interest to an alanine. The mutated proteins are expressed and probed in the binding assay." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0810 ! substitution analysis
[Term]
id: MI:0006
name: anti bait coimmunoprecipitation
def: "A specific antibody for the molecule of interest (bait) is available, this is used to generate a high affinity resin to capture the endogenous bait present in a sample." [PMID:7708014]
subset: PSI-MI_slim
synonym: "anti bait coip" EXACT PSI-MI-short []
is_a: MI:0019 ! coimmunoprecipitation
[Term]
id: MI:0007
name: anti tag coimmunoprecipitation
def: "A specific antibody for the molecule of interest is not available, therefore the bait protein is expressed as a hybrid protein fused to a tag peptide/protein for which efficient and specific antibodies or a specific ligand are available." [PMID:7708014]
subset: PSI-MI_slim
synonym: "anti tag coip" EXACT PSI-MI-short []
is_a: MI:0019 ! coimmunoprecipitation
[Term]
id: MI:0008
name: array technology
def: "In this class of methodologies, the molecules to be tested are presented ordered in an array format (typically at high density) on planar supports. The characteristics and chemical nature of the planar support can vary. This format permits the simultaneous assay, in controlled conditions, of several thousand proteins/peptides/nucleic acids for different functions, for instance their ability to bind any given molecule." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0400 ! affinity technology
[Term]
id: MI:0009
name: bacterial display
def: "The protein of interest is presented on the outer membrane of Gram negative bacteria by expressing it as a fusion partner to peptide signals that direct heterologous proteins to the cell surface. For instance, a single chain Fv (scFv) antibody fragment, consisting of the variable heavy and variable light domains from two separate anti-digoxin monoclonal antibodies, was displayed on the outer membrane of Escherichia coli by fusing it to an Lpp-OmpA. Similar systems have also been developed for gram positive bacteria. Fluorescence-activated cell sorting (FACS), is used to specifically select clones displaying a protein binding to scFv-producing cells." [PMID:10436088, PMID:8248129]
subset: PSI-MI_slim
is_a: MI:0034 ! display technology
is_a: MI:0054 ! fluorescence-activated cell sorting
[Term]
id: MI:0010
name: beta galactosidase complementation
def: "Beta-galactosidase activity can be used to monitor the interaction of chimeric proteins. Pairs of inactive beta gal deletion mutants are capable of complementing to restore activity when fused to interacting protein partners. Critical to the success of this system is the choice of two poorly complementing mutant moieties, since strongly complementing mutants spontaneously assemble and produce functional beta-gal activity detectable in absence of any fused protein fragment." [PMID:12042868, PMID:9237989]
subset: PSI-MI_slim
synonym: "beta galactosidase" EXACT PSI-MI-short []
is_a: MI:0090 ! protein complementation assay
[Term]
id: MI:0011
name: beta lactamase complementation
def: "This strategy is based on a protein fragment complementation assay (PCA) of the enzyme TEM-1 beta-lactamase. The approach includes a simple colorimetric in vitro assays using the cephalosporin nitrocefin and assays in intact cells using the fluorescent substrate CCF2/AM. The combination of in vitro colorimetric and in vivo fluorescence assays of beta-lactamase in mammalian cells permits a variety of sensitive and high-throughput large-scale applications." [PMID:12042868]
subset: PSI-MI_slim
synonym: "beta lactamase" EXACT PSI-MI-short []
is_a: MI:0090 ! protein complementation assay
[Term]
id: MI:0012
name: bioluminescence resonance energy transfer
def: "In this variation of the FRET assay the donor fluorophore is replaced by a luciferase (typically Renilla luciferase). In the presence of its substrate, the luciferase catalyses a bioluminescent reaction that excites the acceptor fluorophore through a resonance energy transfer mechanism. As with FRET the energy transfer occurs only if the protein fused to the luciferase and the one fused to the acceptor fluorophore are in close proximity (10-100 Angstrom)." [PMID:10725388, PMID:9874787]
subset: PSI-MI_slim
synonym: "BRET" EXACT PSI-MI-alternate []
synonym: "bret" EXACT PSI-MI-short []
synonym: "LRET" EXACT PSI-MI-alternate []
is_a: MI:0051 ! fluorescence technology
[Term]
id: MI:0013
name: biophysical
def: "The application of physical principles and methods to biological experiments." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0045 ! experimental interaction detection
[Term]
id: MI:0014
name: adenylate cyclase complementation
def: "Adenylate cyclase is encoded by the cyaA gene and contains a catalytic domain which can be proteolytically cleaved into two complementary fragments, T25 and T18, which remain associated in the presence of calmodulin in a fully active ternary complex. In the absence of calmodulin, the mixture of the two fragments does not exhibit detectable activity, suggesting that the two fragments do not associate. When expressed in an adenylate cyclase-deficient E. coli strain (E. coli lacks calmodulin or calmodulin-related proteins), the T25 and T18 fragments fused to putative interacting proteins are brought into close association which result in cAMP synthesis. The level of reconstructed adenylate cyclase can be estimated by monitoring the expression of a cAMP dependent reporter gene. The T25 tagged protein is generally regarded as the bait, the T18 as the prey." [PMID:9576956]
subset: PSI-MI_slim
synonym: "adenylate cyclase" EXACT PSI-MI-short []
synonym: "bacterial two-hybrid" EXACT PSI-MI-alternate []
is_a: MI:0090 ! protein complementation assay
[Term]
id: MI:0016
name: circular dichroism
def: "Circular dichroism (CD) is observed when optically active molecules absorb left and right hand circularly polarized light slightly differently. Linearly polarized light can be viewed as a superposition of two components of circularly polarized light of equal amplitude and phase but opposite handness. When this light passes through an optically active sample the two polarized components are absorbed differently. The difference in left and right handed absorbance A(l)- A(r) is the signal registered in CD spectra. This signal displays distinct features corresponding to different secondary structures present in peptides, proteins and nucleic acids. The analysis of CD spectra can therefore yield valuable information about the secondary structure of biological macromolecules and the interactions among molecules that influence their structure." [PMID:11578931]
subset: PSI-MI_slim
synonym: "CD" EXACT PSI-MI-alternate []
synonym: "cd" EXACT PSI-MI-short []
is_a: MI:0013 ! biophysical
[Term]
id: MI:0017
name: classical fluorescence spectroscopy
def: "Proteins contain endogenous fluorophores such as tryptophan residue and heme or flavins groups. Protein folding and protein-protein interaction can be studied by monitoring changes in the tryptophan environment detected by changes in its intrinsic fluorescence. Changes in the fluorescence emission spectrum on complex formation can occur either due to a shift in the wavelength of maximum fluorescence emission or by a shift in fluorescence intensity caused by the mixing of two proteins. The interaction of two proteins causes a shift in the fluorescence emission spectrum relative to the sum of the individual fluorescence spectra, resulting in a difference spectrum [F (complex)-2 F (sum)], which is a measurable effect of the interaction. Loss of fluorescence signal from a substrate can be used to measure protein cleavage." [PMID:7708014]
subset: PSI-MI_slim
synonym: "fluorescence spectr" EXACT PSI-MI-short []
is_a: MI:0051 ! fluorescence technology
[Term]
id: MI:0018
name: two hybrid
def: "The classical two-hybrid system is a method that uses transcriptional activity as a measure of protein-protein interaction. It relies on the modular nature of many site-specific transcriptional activators (GAL 4) , which consist of a DNA-binding domain and a transcriptional activation domain. The DNA-binding domain serves to target the activator to the specific genes that will be expressed, and the activation domain contacts other proteins of the transcriptional machinery to enable transcription to occur. The two-hybrid system is based on the observation that the two domains of the activator need to be non-covalently brought together by the interaction of any two proteins. The application of this system requires the expression of two hybrid. Generally this assay is performed in yeast cell, but it can also be carried out in other organism. The bait protein is fused to the DNA binding molecule, the prey to the transcriptional activator." [PMID:10967325, PMID:12634794, PMID:1946372]
subset: PSI-MI_slim
synonym: "2 hybrid" EXACT PSI-MI-short []
synonym: "2-hybrid" EXACT PSI-MI-alternate []
synonym: "2H" EXACT PSI-MI-alternate []
synonym: "2h" EXACT PSI-MI-alternate []
synonym: "classical two hybrid" EXACT PSI-MI-alternate []
synonym: "Gal4 transcription regeneration" EXACT PSI-MI-alternate []
synonym: "two-hybrid" EXACT PSI-MI-alternate []
synonym: "Y-2H" RELATED []
synonym: "Y2H" EXACT []
synonym: "yeast two hybrid" EXACT PSI-MI-alternate []
is_a: MI:0232 ! transcriptional complementation assay
[Term]
id: MI:0019
name: coimmunoprecipitation
def: "In this approach an antibody, specific for the molecule of interest (bait) or any tag expressed within a fusion protein, is used to separate the bait from a molecular mixture or a cell lysate and to capture its ligand simultaneously. The partners that bind to the bait molecule retained by the resin can then be eluted and identified. The antibody may be free or bound to a matrix during this process." [PMID:7708014]
subset: PSI-MI_slim
synonym: "co-immunoprecipitation" EXACT PSI-MI-alternate []
synonym: "Co-IP" EXACT PSI-MI-alternate []
synonym: "CoIp" EXACT PSI-MI-alternate []
synonym: "coip" EXACT PSI-MI-short []
synonym: "immunoprecipitation" EXACT PSI-MI-alternate []
is_a: MI:0004 ! affinity chromatography technology
[Term]
id: MI:0020
name: transmission electron microscopy
def: "Microscopy technique in which a beam of electrons is transmitted through a sample to form an image. Samples can be purified molecules, for which no staining is required in order to detect interaction, or tissue/cells. In the latter case, during the treatment for microscope analysis a tissue section is incubated with high-specificity antibodies coupled to heavy metals (e.g. gold). Any tissue section can then be analysed by electron microscopy to localise the target proteins within the cell. This method supports very high resolution colocalisation of different molecules in a cell." [PMID:14755292]
subset: PSI-MI_slim
synonym: "tem" EXACT PSI-MI-short []
is_a: MI:0040 ! electron microscopy
[Term]
id: MI:0021
name: colocalization by fluorescent probes cloning
def: "Two proteins can be localised to cell compartments, in the same experiment, if they are expressed as chimeric proteins fused to distinct proteins fluorescing at different wavelengths (Green Fluorescent Protein and Red Fluorescent Protein for example). Using a confocal microscope the two proteins can be visualized in living cells and it can be determined whether they have the same subcellular location. Fluorescence microscopy of cells expressing a GFP fusion protein can also demonstrate dynamic processes such as its translocation from one subcellular compartment to another.\nOBSOLETE: use imaging technique (MI:0428) and specific probe as feature of each interacting protein." [PMID:14755292]
subset: PSI-MI_slim
synonym: "coloc fluoresc probe" EXACT PSI-MI-short []
is_obsolete: true
[Term]
id: MI:0022
name: colocalization by immunostaining
def: "The subcellular location of a protein can be demonstrated by treating cells fixed on a microscope slide with an antibody specific for the protein of interest. A secondary antibody conjugated with a reactive enzyme (e.g. horseradish peroxidase) is then added. Following a washing step to remove the unbound secondary ligand, a chromogenic substrate (e.g. 3,3', 5,5' tetramethyl benzidine chromogen [TMB]) is converted to a soluble coloured product by the conjugated enzyme and can then be visualised by standard microscopic techniques.\nOBSOLETE since combination of Interaction Detection Method and Interaction Type.Consider using the Interaction Detection Method imaging techniques (MI:0428) coupled with Interaction Type colocalisation (MI:0403) and Participant detection immunostaining (MI:0422) instead." [PMID:14755292]
subset: PSI-MI_slim
synonym: "coloc immunostaining" EXACT PSI-MI-short []
synonym: "Immunofluorescence Staining" EXACT PSI-MI-alternate []
synonym: "Immunostaining" EXACT PSI-MI-alternate []
is_obsolete: true
[Term]
id: MI:0023
name: colocalization/visualisation technologies
def: "Techniques enabling the identification of the subcellular localisation of a protein or complex. Two different proteins show a similar distribution in the cell are said to co-localise. Obsolete since combination of Interaction Detection Method and Interaction Type.\nOBSOLETE. Consider using imaging techniques (MI:0428) as interaction detection method coupled with colocalisation (MI:0401) as interaction type and predetermined (MI:0396) as participant detection." [PMID:14755292]
subset: PSI-MI_slim
synonym: "coloc visual technol" EXACT PSI-MI-short []
is_obsolete: true
[Term]
id: MI:0024
name: confirmational text mining
def: "Text mining is used to support interactions which have been determined by other methods." [PMID:14755292]
subset: PSI-MI_slim
synonym: "conformational tm" EXACT PSI-MI-short []
is_a: MI:0110 ! text mining
[Term]
id: MI:0025
name: copurification
def: "Approaches designed to separate cell components on the basis of their physicochemical properties. The observation that two or more proteins copurify in one or several conditions is taken as an indication that they form a molecular complex.\nOBSOLETE since too non-specific. Consider use of cosedimentation (MI:0027) or comigration in non denaturing gel electrophoresis (MI:0404) or affinity chromatography technologies (MI:0004) or molecular sieving (MI:0071) or for unspecific cases biochemical (MI:0401)." [PMID:14755292]
subset: PSI-MI_slim
is_obsolete: true
[Term]
id: MI:0026
name: correlated mutations
def: "Pairs of multiple alignments of orthologous sequences are used to identify potential interacting partners as proteins that show covariation of their residue identities between different species. Proteins displaying inter-protein correlated mutations during evolution are likely to be interacting proteins due to co-adapted evolution of their protein interacting interfaces." [PMID:11933068]
subset: PSI-MI_slim
is_a: MI:0101 ! sequence based prediction
is_a: MI:0660 ! feature prediction
[Term]
id: MI:0027
name: cosedimentation
def: "Separation of a mixture of molecules under the influence of a force such as artificial gravity. Molecules sedimenting together are assumed to interact." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0401 ! biochemical
[Term]
id: MI:0028
name: cosedimentation in solution
def: "The ultracentrifuge can be used to characterise and/or purify macromolecules in solution according to their mass and hydrodynamic properties. Sedimentation studies provide information about the molecular weight and shape of a molecule. It is also possible to measure the association state of the sample. Both the mass of a molecule and its shape, that influences the friction forces and diffusion that counterbalances gravity, determine the sedimentation speed." [PMID:10410796]
subset: PSI-MI_slim
synonym: "solution sedimentati" EXACT PSI-MI-short []
is_a: MI:0027 ! cosedimentation
[Term]
id: MI:0029
name: cosedimentation through density gradient
def: "Sedimentation through a density gradient measures the sedimentation rate of a mixture of proteins through either a glycerol or sucrose gradient. Two interacting proteins will sediment mostly as a complex at concentrations above the binding constant. By varying the concentration of one or both of the complex constituents and taking into account the dilution of the species during sedimentation, one can reasonably accurately estimate the binding constant." [PMID:10410796]
subset: PSI-MI_slim
synonym: "density sedimentation" EXACT PSI-MI-short []
is_a: MI:0027 ! cosedimentation
[Term]
id: MI:0030
name: cross-linking study
def: "Analysis of complexes obtained by input of energy or chemical treatments, or by introducing cysteines followed by oxidation to promote the formation of covalent bonds among molecules in close proximity." [PMID:14755292]
subset: PSI-MI_slim
synonym: "crosslink" EXACT PSI-MI-short []
is_a: MI:0401 ! biochemical
[Term]
id: MI:0031
name: protein cross-linking with a bifunctional reagent
def: "Cross-linking agents induce the formation of covalent bonds among proteins that are neighbours. The cross-linker may be a bifunctional molecule having two reactive ends linked by a spacer, often containing a disulfide bond. When a reducing agent is added the disulfide bridge is cleaved, the cross-linked pairs are released and can be identified. There are various classes of cross-linkers, the most common are those having photoreactive groups that become reactive fluorophores when activated by UV light thereby resulting in photolabeling the cross-linked moieties." [PMID:10679368, PMID:7708014]
subset: PSI-MI_slim
synonym: "bifunctional agent crosslink" EXACT PSI-MI-short []
synonym: "Label transfer techniques" EXACT PSI-MI-alternate []
synonym: "Photoaffinity labelling" EXACT PSI-MI-alternate []
is_a: MI:0030 ! cross-linking study
[Term]
id: MI:0032
name: de novo protein sequencing by mass spectrometry
def: "The strategy to determine the complete amino acid sequence of a protein by mass spectrometry relies on the generation of a nested set of fragments differing by one amino acid. This reveals the identity of the residue that has been removed at each degradation step by measuring the mass difference of fragments differing of one residue. Peptide fragments can be obtained by protease treatment combined with the fragmentation promoted by collision (or other methods) within a tandem mass spectrometer. This approach can be carried out with LC MS/MS (Liquid Chromatography Tandem Mass Spectrometry), nanoESI MS/MS (nanoElectrospray Ionisation tandem mass spectrometry), or FTMS (Fourier Transform mass spectrometry) instruments." [PMID:10984529]
subset: PSI-MI_slim
synonym: "de novo protein sequence" EXACT PSI-MI-short []
synonym: "MS/MS" RELATED []
is_a: MI:0093 ! protein sequence identification
is_a: MI:0427 ! Identification by mass spectrometry
is_a: MI:0659 ! experimental feature detection
[Term]
id: MI:0033
name: deletion analysis
def: "In this approach, once a molecule is demonstrated to participate in an interaction, several deletion derivatives are produced and tested in the binding assay to identify the minimal fragment (domain) that can still support the interaction." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0074 ! mutation analysis
[Term]
id: MI:0034
name: display technology
def: "All the methods that permit the physical linking of a protein/peptide to its coding sequence. As a consequence affinity purification of the displayed peptide results in the genetic enrichment of its coding sequence. By these technologies genes encoding a peptide with desired binding properties can be selected over an excess of up to 1012 unrelated molecules." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0400 ! affinity technology
[Term]
id: MI:0035
name: docking
def: "Predicts the structure of a molecular complex from the unbound structures of its components. The initial approach in the majority of docking procedures is based largely on the 'rigid-body' assumption, whereby the proteins are treated as solid objects. Initial scoring of a complex is based on geometric fit or surface complementarity. This generally requires some knowledge of the binding site to limit the number of solutions." [PMID:11478868, PMID:9631301]
subset: PSI-MI_slim
is_a: MI:0105 ! structure based prediction
is_a: MI:0577 ! feature prediction from structure
[Term]
id: MI:0036
name: domain fusion
def: "The rosetta stone, or domain fusion procedure, is based on the assumption that proteins whose homologues in other organisms happen to be fused into a single protein chain are likely to interact or to be functionally related." [PMID:10573422]
subset: PSI-MI_slim
synonym: "Rosetta Stone" EXACT PSI-MI-alternate []
is_a: MI:0058 ! genome based prediction
is_a: MI:0101 ! sequence based prediction
[Term]
id: MI:0037
name: domain profile pairs
def: "This approach uses a protein interaction network of a given organism to infer interaction in another organism using information about the interacting region. The regions or domains involved in interactions are clustered if they share sequence similarity and have common interacting partners. The resulting domain profiles are then used to screen the proteome of another organism and domain-domain interactions are inferred. Ultimately, an inferred protein interaction map is built in this second organism." [PMID:11473021]
subset: PSI-MI_slim
is_a: MI:0046 ! experimental knowledge based
is_a: MI:0101 ! sequence based prediction
is_a: MI:0660 ! feature prediction
[Term]
id: MI:0038
name: dynamic light scattering
def: "In dynamic light scattering, particle diffusion in solution gives rise to fluctuations in the intensity of the scattered light on the microsecond scale. The hydrodynamic radius of the particles can be easily calculated." [PMID:9013660]
subset: PSI-MI_slim
synonym: "dls" EXACT PSI-MI-short []
is_a: MI:0067 ! light scattering
[Term]
id: MI:0039
name: edman degradation
def: "In this procedure the N-terminus amino acid is cleaved from a polypeptide and identified by high-pressure liquid chromatography. The cycle is repeated on the ever-shortening polypeptide until all the residues are identified. On average only 20-30 consecutive cycles can be performed and lead to amino acid identification. Longer polypeptides or full length proteins must be cleaved by specific protease before Edman degradation and their sequences built by fragment overlapping." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0433 ! partial identification of protein sequence
[Term]
id: MI:0040
name: electron microscopy
def: "Electron microscopy methods provide insights into the structure of biological macromolecules and their supramolecular assemblies. Resolution is on average around 10 Angstroms but can reach the atomic level when the samples analysed are 2D crystals. Different types of samples can be analysed by electron microscopy: crystals, single particles like viruses, macromolecular complexes or entire cells and tissue sections. Samples can be chemically fixed or vitrified by rapid freezing in liquid ethane, and then transferred into the electron microscope. Data collection consists of the recording of electron diffraction data (2D crystals) and images. Depending on the type of sample, different approaches are used to analyse and merge images and electron diffraction data." [PMID:11785754]
subset: PSI-MI_slim
synonym: "Electron cryomicroscopy" EXACT PSI-MI-alternate []
synonym: "Electron crystallography" EXACT PSI-MI-alternate []
is_a: MI:0428 ! imaging technique
[Term]
id: MI:0041
name: electron nuclear double resonance
def: "A combination of NMR and EPR. The lines in the EPR spectrum that are caused by coupling of an unpaired electron nearby nuclei change in intensity when these nuclei are excited at their NMR frequency." [PMID:11817959, PMID:11988476, PMID:12186859]
subset: PSI-MI_slim
synonym: "ENDOR" EXACT PSI-MI-alternate []
synonym: "endor" EXACT PSI-MI-short []
is_a: MI:0043 ! electron resonance
[Term]
id: MI:0042
name: electron paramagnetic resonance
def: "EPR (also called ESR, Electron Spin Resonance) spectroscopy is analogous to NMR, but is based on the excitation of unpaired electrons instead of nuclei. Unpaired (single) electrons are only found in radicals and some metal ions (paramagnetic species); the EPR spectrum provides information about the environment and mobility of the paramagnetic species. The magnetic interaction of two paramagnetic centres in a protein can be used to calculate the distance between them; this allows studies of the movements and interactions of protein segments. In proteins without any intrinsic unpaired electrons it is possible to attach a radical probe (spin label). Stable nitroxide radicals can be bound to amino acid residues, in analogy with fluorescent probes. In combination with site directed mutagenesis this method is used in particular to study structure and assembly of membrane proteins, by measuring with EPR whether an amino acid is in a polar or non polar environment." [PMID:11817959]
subset: PSI-MI_slim
synonym: "EPR" EXACT PSI-MI-alternate []
synonym: "epr" EXACT PSI-MI-short []
synonym: "ESR" EXACT PSI-MI-alternate []
is_a: MI:0043 ! electron resonance
[Term]
id: MI:0043
name: electron resonance
def: "A form of spectroscopy in which the absorption of microwave by a sample in a strong magnetic field is used to study atoms or molecules with unpaired electrons." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0013 ! biophysical
is_a: MI:0659 ! experimental feature detection
[Term]
id: MI:0045
name: experimental interaction detection
def: "Methods based on laboratory experiments to determine an interaction." [PMID:14755292]
subset: PSI-MI_slim
synonym: "experimental interac" EXACT PSI-MI-short []
is_a: MI:0001 ! interaction detection method
[Term]
id: MI:0046
name: experimental knowledge based
def: "Predictive algorithms that rely on the information obtained by experimental results." [PMID:14755292]
subset: PSI-MI_slim
synonym: "experimental info" EXACT PSI-MI-short []
is_a: MI:0063 ! interaction prediction
[Term]
id: MI:0047
name: far western blotting
def: "Proteins are fractionated by PAGE (SDS-polyacrylamide gel electrophoresis), transferred to a nitrocellulose membrane and tested for the ability to bind to a protein, a peptide, or any other ligand. Cell lysates can also be fractionated before gel electrophoresis to increase the sensitivity of the method for detecting interactions with rare proteins. Denaturants are removed during the blotting procedure, which allows many proteins to recover (or partially recover) activity. However, if biological activity is not recoverable, the proteins can be fractionated by a non denaturing gel system. This variation of the method eliminates the problem of activity regeneration and allows the detection of binding when the presence of a protein complex is required for binding. The protein probe can be prepared by any one of several procedures, while fusion affinity tags greatly facilitate purification. Synthesis in E. coli with a GST fusion, epitope tag, or other affinity tag is most commonly used. The protein of interest can then be radioactively labelled, biotinylated, or used in the blotting procedure as an unlabeled probe that is detected by a specific antibody." [PMID:7708014]
subset: PSI-MI_slim
synonym: "Affinity blotting" EXACT PSI-MI-alternate []
is_a: MI:0892 ! solid phase assay
[Term]
id: MI:0048
name: filamentous phage display
def: "Filamentous phages (M13, f1, fd) have been extensively used to develop and implement the technology of phage display. Repertoires of relatively short peptides of random amino acid sequences or cDNA libraries have been constructed and searched successfully. Most experiments have taken advantage of the ability to assemble phages decorated with hybrid versions of the receptor protein pIII or of the major coat protein pVIII. Both systems allow the display of foreign peptides by fusion to the amino-terminus of the capsid protein but differ in the number of peptide copies that can be displayed on each phage particle. Display libraries of very diverse protein fragments have been constructed by fusing either genomic or cDNA fragments to gene III or gene VIII." [PMID:7682645]
subset: PSI-MI_slim
synonym: "filamentous phage" EXACT PSI-MI-short []
is_a: MI:0084 ! phage display
[Term]
id: MI:0049
name: filter binding
def: "A method in which separation depends upon the ability of one participant to bind to a filter or membrane which the other participants do not. Molecules interacting with the bound molecule will also be retain on the filter. For example, proteins expressed by different clones of an expression library are bound to a nitrocellulose membrane, by colony (bacterial library) or plaque (phage library) blotting. A labelled protein can then be used as a probe to identify clones expressing proteins that interact with the probe. Interactions occur on the nitrocellulose filters. The method is highly general and therefore widely applicable. A variety of approaches can be used to label the ligand, alternatively the ligand can be detected by a specific antibody." [PMID:7708014]
subset: PSI-MI_slim
synonym: "dot blot" RELATED []
synonym: "Filter overlay assay" EXACT PSI-MI-alternate []
is_a: MI:0892 ! solid phase assay
[Term]
id: MI:0050
name: flag tag coimmunoprecipitation
def: "The protein of interest is expressed as a fusion to the peptide DYKDDDDKV for which antibodies are commercially available. Sometimes multiple copies of the peptide are fused in tandem.\nOBSOLETE redundant term. Map to feature type: flag-tagged (MI:0518) and Interaction detection method: anti tag coimmunoprecipitation (MI:0007)." [PMID:14755292]
subset: PSI-MI_slim
synonym: "flag tag coip" EXACT PSI-MI-short []
is_obsolete: true
[Term]
id: MI:0051
name: fluorescence technology
def: "Techniques based upon the measurement of the emission of one or more photons by a molecule activated by the absorption of a quantum of electro-magnetic radiation. Typically the emission, which is characterised by a wavelength that is longer than the one of excitatory radiation, occurs within 10-8 seconds." [PMID:14755292]
subset: PSI-MI_slim
synonym: "fluorescence" EXACT PSI-MI-short []
is_a: MI:0013 ! biophysical
[Term]
id: MI:0052
name: fluorescence correlation spectroscopy
def: "FCS monitors the random motion of fluorescently labelled molecules inside a defined volume irradiated by a focused laser beam. These fluctuations provide information on the rate of diffusion or diffusion time of a particle and this is directly dependent on the particle mass. As a consequence, any increase in the mass of a biomolecule, e.g. as a result of an interaction with a second molecule, is readily detected as an increase in the diffusion time of the particle. From these results the concentration of the different molecules can be calculated as well as their binding constant." [PMID:10733953]
subset: PSI-MI_slim
synonym: "FCS" EXACT PSI-MI-alternate []
synonym: "fcs" EXACT PSI-MI-short []
synonym: "fluctuation correlation specctrometry" RELATED []
is_a: MI:0051 ! fluorescence technology
[Term]
id: MI:0053
name: fluorescence polarization spectroscopy
def: "Because of the long lifetimes of excited fluorescent molecules (nanoseconds), fluorescence can be used to monitor the rotational motion of molecules, which occurs on this timescale. This is accomplished experimentally by excitation with plane-polarized light, followed by measurement of the emission at parallel and perpendicular planes. Since rotational correlation times depend on the size of the molecule, this method can be used to measure the binding of two proteins because the observed polarization increase when a larger complex is formed. A fluorescence anisotropy experiment is normally carried out with a protein bearing a covalently added fluorescent group, which increases both the observed fluorescence lifetime of the excited state and the intensity of the fluorescent signal. Residue modification can be assessed by addition of an antibody which binds to the modified residue and alters the molecular weight of the complex. A variation of this technique has been used to show interaction of a DNA binding protein with another protein. In this case the DNA rather than protein is fluorescently labelled." [PMID:12805227, PMID:7708014]
subset: PSI-MI_slim
synonym: "Fluorescence anisotropy" EXACT PSI-MI-alternate []
synonym: "FPS" EXACT PSI-MI-alternate []
synonym: "fps" EXACT PSI-MI-short []
is_a: MI:0051 ! fluorescence technology
[Term]
id: MI:0054
name: fluorescence-activated cell sorting
def: "Cells in suspension flow through a laser beam, the scattered light or emitted fluorescence is measured, filtered and converted to digital values. Cells can be sorted according to their properties. Using flow cytometry, any fluorescent or light scattering experiment can be carried out on entire cells. With this instrument, interactions occurring either on cell surfaces or in any other subcellular location can be studied by using suitable fluorescent labels." [PMID:11988464]
subset: PSI-MI_slim
synonym: "FACS" EXACT PSI-MI-alternate []
synonym: "facs" EXACT PSI-MI-short []
synonym: "Flow cytometry" EXACT PSI-MI-alternate []
is_a: MI:0051 ! fluorescence technology
[Term]
id: MI:0055
name: fluorescent resonance energy transfer
def: "FRET is a quantum mechanical process involving the radiationless transfer of energy from a donor fluorophore to an appropriately positioned acceptor fluorophore. The fluorophores are genetically fused to the protein in analysis and cotransfected. Three basic conditions must be fulfilled for FRET to occur between a donor molecule and acceptor molecule. First, the donor emission spectrum must significantly overlap the absorption spectrum of the acceptor. Second, the distance between the donor and acceptor fluorophores must fall within the range 20 to 100 Angstrom. Third, the donor and acceptor fluorophores must be in favourable orientations." [PMID:11558993]
subset: PSI-MI_slim
synonym: "FRET" EXACT PSI-MI-alternate []
synonym: "fret" EXACT PSI-MI-short []
synonym: "FRET analysis" EXACT PSI-MI-alternate []
synonym: "RET" EXACT PSI-MI-alternate []
is_a: MI:0051 ! fluorescence technology
[Term]
id: MI:0056
name: full identification by DNA sequencing
def: "Sequencing occurs during the course of the experiment. DNA sequencing is the process of determining the nucleotide order of a given DNA fragment. Thus far, most DNA sequencing has been performed using the chain termination method developed by Frederick Sanger. This technique uses sequence-specific termination of a DNA synthesis reaction using modified nucleotide substrates. However, new sequencing technologies such as Pyrosequencing are generating the majority of data." [PMID:14755292]
subset: PSI-MI_slim
synonym: "full dna sequence" EXACT PSI-MI-short []
is_a: MI:0078 ! nucleotide sequence identification
is_a: MI:0659 ! experimental feature detection
[Term]
id: MI:0057
name: gene neighbourhood
def: "Gene pairs that show a conserved topological neighbourhood in many prokaryotic genomes are considered by this approach to encode interacting or functionally related proteins. By measuring the physical distance of any given gene pair in different genomes, interacting partners are inferred." [PMID:9787636]
subset: PSI-MI_slim
is_a: MI:0058 ! genome based prediction
[Term]
id: MI:0058
name: genome based prediction
def: "Methods that require fully sequenced genomes either because they are based on the comparison of genome topology or on the identification of orthologous sequences in different genomes." [PMID:14755292]
subset: PSI-MI_slim
synonym: "genome prediction" EXACT PSI-MI-short []
is_a: MI:0063 ! interaction prediction
[Term]
id: MI:0059
name: gst pull down
def: "The bait protein is expressed and purified as a fusion to the glutathione S-tranferase protein. The bait protein is normally attached to a glutathione sepharose resin or alternatively to a support containing an anti-GST antibody.\nOBSOLETE redundant term. Map to feature type : gst-tagged (MI:0519) and Interaction detection method: pull down (MI:0096)." [PMID:14755292]
subset: PSI-MI_slim
is_obsolete: true
[Term]
id: MI:0060
name: ha tag coimmunoprecipitation
def: "The protein of interest is expressed as a fusion to the peptide YPYDVPDYA (a fragment of the influenza hemaglutinin protein) for which antibodies are commercially available.\nOBSOLETE redundant term. Map to feature type : ha-tagged (MI:0520) and Interaction detection method: anti tag coimmunoprecipitation (MI:0007)." [PMID:14755292]
subset: PSI-MI_slim
synonym: "ha tag coip" EXACT PSI-MI-short []
is_obsolete: true
[Term]
id: MI:0061
name: his pull down
def: "The bait protein is expressed and purified fused to an amino or carboxyterminal tail containing a variable number of histidines. The bait protein is normally attached to a metal (usually nickel) resin.\nOBSOLETE redundant term. Map to feature type : his-tagged (MI:0521) and Interaction detection method: pull down (MI:0096)." [PMID:14755292]
subset: PSI-MI_slim
is_obsolete: true
[Term]
id: MI:0062
name: his tag coimmunoprecipitation
def: "The protein of interest is expressed as a fusion to a poly-His tail. This permits purification by chromatography over a metal column or by binding to commercially available anti poly-His antibodies.\nOBSOLETE redundant term. Map to feature type: his-tagged (MI:0521) and Interaction detection method: anti tag coimmunoprecipitation (MI:0007)." [PMID:14755292]
subset: PSI-MI_slim
synonym: "his tag coip" EXACT PSI-MI-short []
is_obsolete: true
[Term]
id: MI:0063
name: interaction prediction
def: "Computational methods to predict an interaction." [PMID:14755292]
subset: PSI-MI_slim
synonym: "in silico methods" EXACT PSI-MI-alternate []
synonym: "predicted interac" EXACT PSI-MI-short []
is_a: MI:0001 ! interaction detection method
[Term]
id: MI:0064
name: interologs mapping
def: "Protein interactions, experimentally detected in an organism, are extended to a second organism assuming that homologue proteins, in different organisms, maintain their interaction properties." [PMID:11731503]
subset: PSI-MI_slim
synonym: "Homology based interaction prediction" EXACT PSI-MI-alternate []
is_a: MI:0046 ! experimental knowledge based
is_a: MI:0101 ! sequence based prediction
[Term]
id: MI:0065
name: isothermal titration calorimetry
def: "Isothermal titration calorimetry (ITC) measures directly the energy associated with a chemical reaction triggered by the mixing of two components. A typical ITC experiment is carried out by the stepwise addition of one of the reactants (~10-6 L per injection) into the reaction cell (~1mL) containing the second reactant. The chemical reaction occurring after each injection either releases or absorbs heat (qi) proportional to the amount of ligand that binds to the protein with a characteristic binding enthalpy (DH). As modern ITC instruments operate on the heat compensation principle, the instrumental response (measured signal) is the amount of power (microcalories per second) necessary to maintain constant the temperature difference between the reaction and the reference cells. Because the amount of uncomplexed protein available progressively decreases after each successive injection, the magnitude of the peaks becomes progressively smaller until complete saturation is achieved. The difference between the concentration of bound ligand in the ith and (i-1)th injections depends on the binding constant Ka and the total ligand injected. The calculations depend on the binding model (number of substrates). Analysis of the data yields DH and DG = -RTlnKa. The entropy change is obtained by using the standard thermodynamic expression DG = DH-TDS." [PMID:11785756]
subset: PSI-MI_slim
synonym: "ITC" EXACT PSI-MI-alternate []
synonym: "itc" EXACT PSI-MI-short []
is_a: MI:0013 ! biophysical
[Term]
id: MI:0066
name: lambda phage display
def: "Morphologically classified as one of the siphoviridae, lambda is a temperate bacteriophage of E.coli, with a double-stranded DNA genome. It has an icosahedral head attached to a flexible helical tail. Both the tail protein pV and the head protein pD have been used for displaying (C or N terminally) foreign peptides on the viral capsid." [PMID:7682645]
subset: PSI-MI_slim
synonym: "lambda phage" EXACT PSI-MI-short []
is_a: MI:0084 ! phage display
[Term]
id: MI:0067
name: light scattering
def: "Dynamic and static laser light scattering probes the size, shape, and structure of biological macromolecules or of their assemblies. A beam is focused on an optically clear cylindrical cell containing the sample. Most of the light passes directly through the sample. A small portion of the light is scattered; the scattered light intensity containing information about the scattering particle is detected at an angle (typically in the range 15-180degrees) from the direction of the incident beam." [PMID:9013660]
subset: PSI-MI_slim
is_a: MI:0013 ! biophysical
[Term]
id: MI:0068
name: mass detection of residue modification
def: "Mass spectrometry can be used to characterise chemical modifications within peptides. One approach consists in the observation of a mass difference when a sample is treated with an enzyme that can specifically remove a peptide modification, for instance a phosphatase. The mass difference corresponds to the mass of the chemical group covalently linked to a residue. Such experiments carried out with a MALDI-TOF (Matrix-assisted laser desorption ionization time-of-flight ) do not allow the mapping of the modification site within the sequence, whereas any tandem mass spectrometer (LC MS/MS Liquid Chromatography Tandem Mass Spectrometry, nanoESI MS/MS nanoElectrospray Ionisation tandem mass spectrometry, FTMS Fourier Transform mass spectrometry) provide such information. A second approach consists of the direct mass measurement of the ionized chemical group dissociated from the residue within a tandem mass spectrometer. Both approaches need a prior enrichment of the modified peptide population in the samples with IMAC (Immobilized Metal Affinity Chromatography)or specific anti-modification antibodies." [PMID:11395414, PMID:11875433]
subset: PSI-MI_slim
synonym: "modified residue ms" EXACT PSI-MI-short []
is_a: MI:0659 ! experimental feature detection
[Term]
id: MI:0069
name: mass spectrometry studies of complexes
def: "Mass spectrometric approaches to the study of macromolecular complexes permits the identification of subunit stoichiometry and transient associations. By preserving complexes intact in the mass spectrometer, mass measurement can be used for monitoring changes in different experimental conditions, or to investigate how variations of collision energy affect their dissociation." [PMID:12057199, PMID:12504676]
subset: PSI-MI_slim
synonym: "ms of complexes" EXACT PSI-MI-short []
is_a: MI:0943 ! detection by mass spectrometry
[Term]
id: MI:0070
name: mobility shift
def: "Protein modifications can be identified by gel electrophoresis since any change in the mass and/or the charge of the protein can alter its mobility in PAGE. Although this method does not allow the unequivocal identification of the type of modification that has caused the shift, it is possible, by combining this approach with more direct methods, to correlate the extent of the shift to a specific modification." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0659 ! experimental feature detection
[Term]
id: MI:0071
name: molecular sieving
def: "In sizing columns (gel filtration), the elution position of a protein or of a complex depends on its Stokes radius. Molecules with a radius that is smaller than the bead size are retained and retarded by the interaction with the matrix. The observation that two proteins, loaded on a sieving column, elute in a fraction(s) corresponding to a MW that is larger than the MW of either protein may be taken as an indication that the two proteins interact. Furthermore this technique provides a conceptually simple method for evaluating the affinity of the interaction." [PMID:7708014]
subset: PSI-MI_slim
synonym: "Gel Filtration" EXACT PSI-MI-alternate []
synonym: "Size Exclusion Chromatography" EXACT PSI-MI-alternate []
synonym: "Sizing column" EXACT PSI-MI-alternate []
is_a: MI:0013 ! biophysical
is_a: MI:0091 ! chromatography technology
[Term]
id: MI:0072
name: monoclonal antibody western blot
def: "Western blot assay carried out using monospecific antibodies produced in the supernatant of a cell line obtained by fusing a lymphocyte B to a myeloma cell line or selected by phage display technology." [PMID:14755292]
subset: PSI-MI_slim
synonym: "monoclonal western" EXACT PSI-MI-short []
is_a: MI:0113 ! western blot
[Term]
id: MI:0073
name: mrna display
def: "This method relies on the covalent coupling of mRNA to the nascent polypeptide. The mRNA (natural or artificial) is first covalently linked to a short DNA linker carrying a puromycin moiety. The mRNA mixture is then translated in vitro. When the ribosome reaches the RNA-DNA junction the ribosome stalls and the puromycin moiety enters the peptidyltransferase site of the ribosome and forms a covalent linkage to the nascent polypeptide. As a result the protein and the mRNA are covalently joined and can be isolated from the ribosome and purified. In the current protocol, a cDNA strand is then synthesised to form a less sticky RNA-DNA hybrid and these complexes are finally used for affinity selection. As in most display approaches, several selections cycles (3-6) are sufficient to enrich for mRNAs encoding ligand proteins." [PMID:11551470]
subset: PSI-MI_slim
is_a: MI:0034 ! display technology
[Term]
id: MI:0074
name: mutation analysis
def: "Mutant molecules are produced by random or directed techniques and assayed for their ability to support binding." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0659 ! experimental feature detection
[Term]
id: MI:0075
name: myc tag coimmunoprecipitation
def: "The protein of interest is expressed as a fusion to the peptide EUKLISEED (a fragment of the Myc oncogene protein) for which antibodies are commercially available. Sometimes multiple copies of the peptide are fused in tandem.\nOBSOLETE redundant term. Map to feature type: myc-tagged (MI:0522) and Interaction detection method: anti tag coimmunoprecipitation (MI:0007)." [PMID:14755292]
subset: PSI-MI_slim
synonym: "myc tag coip " EXACT PSI-MI-short []
is_obsolete: true
[Term]
id: MI:0076
name: neural network on interface properties
def: "Neural networks are trained on the properties of residues belonging to a cluster of residues that are neighbours in space on protein surface. The predictor permits the inference of the residues that are likely to be on an interaction interface." [PMID:11455607, PMID:11874449]
subset: PSI-MI_slim
synonym: "interface predictor" EXACT PSI-MI-short []
is_a: MI:0577 ! feature prediction from structure
[Term]
id: MI:0077
name: nuclear magnetic resonance
def: "Nuclear magnetic resonance (NMR) is an effect whereby magnetic nuclei in a magnetic field absorb and re-emit electromagnetic (EM) energy. Certain atomic nuclei, and in particular hydrogen, have a magnetic moment or spin; i.e., they have an intrinsic magnetisation, like a bar magnet. The spin aligns along the strong magnetic field, but can be changed to a misaligned excited state in response to applied radio frequency (RF) pulses of electromagnetic radiation. When the excited hydrogen nuclei relax to their aligned state, they emit RF radiation, which can be measured and displayed as a spectrum. The nature of the emitted radiation depends on the environment of each hydrogen nucleus, and if one nucleus is excited, it will influence the absorption and emission of radiation by other nuclei that lie close to it. It is consequently possible, by an ingenious elaboration of the basic NMR technique known as two-dimensional NMR, to distinguish the signals from hydrogen nuclei in different amino acid residues and to identify and measure the small shifts in these signals that occur when these hydrogen nuclei lie close enough to interact: the size of such a shift reveals the distance between the interacting pair of hydrogen atoms. In this way NMR can give information about the distances between the parts of the interacting molecule. NMR provides information about interacting atoms thereby permitting to obtain information about macromolecular structure and molecular interactions." [PMID:12062432, PMID:12120505]
subset: PSI-MI_slim
synonym: "NMR" EXACT PSI-MI-alternate []
synonym: "nmr" EXACT PSI-MI-short []
is_a: MI:0013 ! biophysical
is_a: MI:0659 ! experimental feature detection
[Term]
id: MI:0078
name: nucleotide sequence identification
def: "Identification of a nucleotide sequence. Depending on the experimental design, nucleotide sequence can be determined before the interaction detection while building a collection of clones or after the selection of randomly generated clones." [PMID:14755292]
subset: PSI-MI_slim
synonym: "nucleotide sequence" EXACT PSI-MI-short []
synonym: "sequence cloning" EXACT PSI-MI-alternate []
is_a: MI:0659 ! experimental feature detection
is_a: MI:0661 ! experimental participant identification
[Term]
id: MI:0079
name: other biochemical technologies
def: "Experimental methods that could not be assigned to the other large group of technologies.\nOBSOLETE use biochemical (MI:0401) instead." [PMID:14755292]
subset: PSI-MI_slim
synonym: "other biochemic tech" EXACT PSI-MI-short []
is_obsolete: true
[Term]
id: MI:0080
name: partial DNA sequence identification by hybridization
def: "Genes are recognised by hybridization of a probe with a fragment of the gene sequence." [PMID:14755292]
subset: PSI-MI_slim
synonym: "partial dna sequence hybrid" EXACT PSI-MI-short []
is_a: MI:1180 ! partial DNA sequence identification
[Term]
id: MI:0081
name: peptide array
def: "The peptide synthesis methods offer numerous opportunities to synthesise and subsequently screen large arrays of synthetic peptides on planar cellulose supports. Discrete spots are arranged as arrays on membrane sheets where each spot is individually accessed by manual or automated delivery of the appropriate reagent solutions. Over the past few years protein-protein recognition, peptide-metal ion interactions, peptide-nucleic acid binding, enzymatic modification of peptides experiments, have been explored using synthetic peptide arrays on planar support." [PMID:11167074]
subset: PSI-MI_slim
is_a: MI:0008 ! array technology
[Term]
id: MI:0082
name: peptide massfingerprinting
def: "This approach leads to protein identification by matching peptide masses, as measured by mass spectrometry, to the ones calculated from in silico fragmentation of a protein sequence database. A peptide mixture from a tryptic digest is analysed by MALDI-MS (Matrix-assisted laser desorption ionization mass spectrometry). The list of peptide masses obtained by MALDI MS is automatically compared to the calculated masses of the predicted peptide fragments for each entry in the database. High mass accuracy is very important in order to obtain a statistically significant and unambiguous match This method is best applied to completely sequenced genomes and well characterised proteomes. However, depending on the data quality, proteins that are highly homologous to already characterised proteins (greater than 80 to 90% sequence identity) can also be identified. The retrieved sequence are evaluated by mass accuracy of the peptides, matching of additional peptide masses in the MALDI spectrum after accounting for common modifications such as oxidation, acrylamidation of cysteine and missed cleavages and the use of secondary information (apparent isoelectric point and molecular weight). If any ambiguity about the identification by MALDI-MS still exists, the results must verified by an other identification method. Peptide mass fingerprint is generally carried out with a MALDI-TOF (Matrix-assisted laser desorption ionization time-of-flight ) instrument but can also be achieved ESI-TOF (Electrospray Ionisation time-of-flight) or LC-MS (Liquid Chromatography-Mass Spectrometry) mass spectrometer." [PMID:10967324, PMID:11752590, PMID:11805826]
subset: PSI-MI_slim
synonym: "fingerprinting" EXACT PSI-MI-short []
is_a: MI:0427 ! Identification by mass spectrometry
is_a: MI:0433 ! partial identification of protein sequence
[Term]
id: MI:0083
name: peptide synthesis
def: "When one of the partners participates in the interaction with a relatively short peptide fragment, it is often convenient to precisely identify the minimal region that supports the interaction by synthesising a series of overlapping peptides and by testing them in the binding assay. Synthetic peptides that are identical with peptides synthesised in vivo are useful experimental tools for such studies. Peptides are routinely synthesised in a test tube from monomeric amino acids by condensation reactions that form peptide bonds. Peptides are constructed sequentially by coupling the C-terminus of a monomeric amino acid to the N-terminus of the growing peptide. To prevent unwanted reactions involving the amino groups and carboxyl groups of the side chains during the coupling steps, a protecting (blocking) group is attached to the side chains. Without these protecting groups, branched peptides would be generated. In the last steps of synthesis, the side chain-protecting groups are removed and the peptide is cleaved from the resin on which synthesis occurs." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0093 ! protein sequence identification
[Term]
id: MI:0084
name: phage display
def: "Peptide sequences or entire proteins can be displayed on phage capsids by fusion to coat proteins to generate a library of fusion phages each displaying a different peptide. Such a library can then be exploited to identify specific phages that display peptides that bind to any given bait molecule for instance an antibody. The selection is performed by a series of cycles of affinity purification known as panning. The bait protein, immobilized on a solid support (plastic, agarose, sepharose, magnetic beads and others) is soaked in the phage mixture and that phage that remains attached to the bait is amplified and carried through a further affinity purification step. Each cycle results in an approximately 1,000-fold enrichment of specific phage and after a few selection rounds (2-4), DNA sequencing of the tight-binding phage reveals only a small number of sequences. Phage display panning experiments can be carried out either on libraries of peptides of random amino acid sequence or on libraries of displaying natural peptides obtained by inserting cDNA fragments into the phage vector (cDNA libraries). Libraries have been assembled on several different phages (Fd, Lambda or T7)." [PMID:10975452, PMID:7708014]
subset: PSI-MI_slim
is_a: MI:0034 ! display technology
[Term]
id: MI:0085
name: phylogenetic profile
def: "The phylogenetic profile of a protein stores information about the presence and the absence of that protein in a set of genomes. By clustering identical or similar profiles, proteins with similar functions and potentially interacting are identified." [PMID:10200254]
subset: PSI-MI_slim
is_a: MI:0058 ! genome based prediction
[Term]
id: MI:0086
name: polyclonal antibody western blot
def: "Western blot assay carried out using a mixture of different antibodies that represent the immune response, normally in an experimental animal, to the protein of interest." [PMID:14755292]
subset: PSI-MI_slim
synonym: "polyclonal western" EXACT PSI-MI-short []
is_a: MI:0113 ! western blot
[Term]
id: MI:0087
name: predictive text mining
def: "Methods based on natural language processing to detect possible interactions between proteins (direct physical interactions or indirect genetic interactions). This includes the detection of non ambiguous protein or gene names and analysis of the relation expressed in a sentence among them." [PMID:11791231]
subset: PSI-MI_slim
synonym: "predictive tm" EXACT PSI-MI-short []
is_a: MI:0110 ! text mining
[Term]
id: MI:0088
name: primer specific pcr
def: "Sequences can be identified in a DNA mixture by launching a PCR (Polymerase Chain Reaction) controlled by sequence specific primers. Such reaction starts only when the hybridization of the primer with a complementary sequence occurs." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0080 ! partial DNA sequence identification by hybridization
[Term]
id: MI:0089
name: protein array
def: "The protein array technology allows the screening of biochemical activities or binding abilities of hundreds or thousands of protein samples in parallel. After synthesis and purification by high-throughput methodologies, the proteins are printed onto the chip by using an instrument (micro-arrayer) that is capable of spotting liquid samples in a reproducible manner onto a planar support. The ordered protein array can then be probed with labelled molecules to identify proteins that bind to the bait." [PMID:10976071, PMID:12067604]
subset: PSI-MI_slim
is_a: MI:0008 ! array technology
[Term]
id: MI:0090
name: protein complementation assay
def: "In the protein-fragment complementation assay, the proteins of interest (\"Bait\" and \"Prey\") are covalently linked at the genetic level to incomplete fragments of a third protein (known as the \"reporter\") and are expressed in vivo, Interaction between the \"bait\" and the \"prey\" proteins brings the fragments of the \"reporter\" protein in close enough proximity to allow them to reform and become the functional reporter protein. Typically enzymes which confer resistance to antibiotics, such as Dihydrofolate reductase or Beta-lactamase, or proteins that give colorimetric or fluorescent signals are used. The Bait protein is generally the protein under study and the methods are readily adaptable to highthroughput mode." [PMID:11495741]
subset: PSI-MI_slim
synonym: "complementation" EXACT PSI-MI-short []
synonym: "PCA" EXACT PSI-MI-alternate []
is_a: MI:0045 ! experimental interaction detection
[Term]
id: MI:0091
name: chromatography technology
def: "Used to separate and/or analyse complex mixtures. The components to be separated are distributed between two phases: a stationary phase (bed) and a mobile phase which percolates through the stationary bed. The nature of the two phases determines the separation criteria exploited by the column such as affinity, ionic charges, size or hydrophobicity of the molecules under analysis. Each type of column can be implemented with the mobile phase under atmospheric or high pressure condition. In this later case columns are designated as High Pressure Liquid Chromatography (HPLC)." [PMID:14755292]
subset: PSI-MI_slim
synonym: "chromatography" EXACT PSI-MI-short []
synonym: "column chromatography" EXACT PSI-MI-alternate []
is_a: MI:0401 ! biochemical
[Term]
id: MI:0092
name: protein in situ array
def: "Protein In Situ Array is a method by which protein arrays are rapidly generated in one step directly from DNA, by cell-free protein expression and simultaneous in situ immobilisation at a surface. Individual genes or fragments are produce by PCR or RT-PCR depending on the source of genetic material using properly designed primers. The PISA is generated by cell-free protein synthesis using coupled transcription and translation to produce a tagged protein, the reaction being carried out on a surface to which the protein adheres as soon as it is synthesised." [PMID:11470888]
subset: PSI-MI_slim
synonym: "PISA" EXACT PSI-MI-alternate []
synonym: "pisa" EXACT PSI-MI-short []
is_a: MI:0089 ! protein array
[Term]
id: MI:0093
name: protein sequence identification
def: "Single amino acid identification along a protein sequence." [PMID:14755292]
subset: PSI-MI_slim
synonym: "protein sequence" EXACT PSI-MI-short []
is_a: MI:0661 ! experimental participant identification
[Term]
id: MI:0094
name: protein staining
def: "A wide range of dyes have been used over the years to visualise proteins in polyacrylamide gels - Coomasie Blue and silver-staining being two classical methods. Fluorescent dyes such as Nile Red and SYPRO Orange are now increasingly used due to their superior dynamic range. Use of non-denaturing gels can allow visualisation of protein protein interactions. Several dyes can be used to specifically indicate residue modification, however this methodology will give no information as the number of residues modified or their position within the protein sequence. Examples include the use of acid fuscian or the fluorescent dansyl hydrazine to show protein glycosylation." [PMID:12015990]
subset: PSI-MI_slim
is_a: MI:0659 ! experimental feature detection
[Term]
id: MI:0095
name: proteinchip(r) on a surface-enhanced laser desorption/ionization
def: "ProteinChip(r) Array technology is a surface-enhanced laser desorption/ionization (SELDI) approach (Ciphergen Biosystems Inc. Fremont, CA, USA) for sample fractionation accomplished by retentate chromatography. Retentate chromatography is performed on ProteinChip Arrays with varying chromatographic properties (e.g. anion exchange, cation exchange, metal affinity and reverse phase). By utilising arrays with differing surface chemistries in parallel and in series, a complex mixture of proteins, as from cells or body fluids, can be resolved into subsets of proteins with common properties. Specific analytes can also be examined by using preactivated arrays to which a bait molecule (such as an antibody or biotinylated DNA) is immobilized and a solution containing the binding partner(s) is presented to the array. This array-based immunoprecipitation or protein-binding experiment has been used with good success to study DNA-binding proteins, receptor-ligand interactions, and protein complexes. Any ligand retained on a SELDI chip can directly be identified by mass spectrometry." [PMID:11827829]
subset: PSI-MI_slim
synonym: "seldi chip" EXACT PSI-MI-short []
synonym: "SELDI ProteinChip" EXACT PSI-MI-alternate []
is_a: MI:0089 ! protein array
[Term]
id: MI:0096
name: pull down
def: "A specific affinity chromatography method where a molecule of interest (bait) is bound to a column, often via an affinity tag expressed as a protein fusion (GST, HIS tag and others) or chemically linked to the bait molecule . The molecule may be expressed or synthesised and purified first, often in an heterologous system, bound to the matrix at high concentration and then challenged with a solution or cellular extract containing the candidate partner molecules. Alternatively, a multi-molecular complex may be adsorbed to the resin and the retained binding molecules subsequently identified." [PMID:14755292]
subset: PSI-MI_slim
synonym: "affinity capture" RELATED []
synonym: "pulldown" RELATED []
is_a: MI:0004 ! affinity chromatography technology
[Term]
id: MI:0097
name: reverse ras recruitment system
def: "In this complementation approach the bait can be any membrane protein (for example a receptor or a channel protein), the prey is cloned as a fusion protein of any cDNA from a library and the coding sequence of cytoplasmic RAS (cdc25 in yeast). If the bait and the prey interact, RAS is recruited close to the membrane and can activate cell growth. This procedure must take place in cells having a mutated RAS (Cdc25-2 yeast strain having a temperature sensitive mutation of RAS) to avoid constitutive growth activation." [PMID:11160938]
subset: PSI-MI_slim
synonym: "reverse RRS" EXACT PSI-MI-alternate []
synonym: "reverse rrs" EXACT PSI-MI-short []
is_a: MI:0090 ! protein complementation assay
[Term]
id: MI:0098
name: ribosome display
def: "This method permits the coupling of phenotype to genotype via the formation of a non-covalent ternary complex between mRNAs and their encoded polypeptides while they are translated in an in vitro system. As a first step a cDNA library is constructed that encodes chimeric proteins in which the natural proteins or protein domains are fused to a C-terminal tether. As a consequence when the mRNA is translated in vitro the domain can fold while the tether is still in the ribosomal tunnel. Furthermore this chimeric mRNAs lack a stop codon, thus preventing release of the mRNA and the polypeptide from the ribosome. High concentrations of magnesium and low temperature further stabilise the ternary complex. Similarly to phage display, these complexes can be used directly to select for nucleic acids encoding proteins with desired properties." [PMID:11551470, PMID:12167034]
subset: PSI-MI_slim
is_a: MI:0034 ! display technology
[Term]
id: MI:0099
name: scintillation proximity assay
def: "SPA relies upon the fact that a beta particle emitted from a radioisotope decay can excite a fluorophore only when it is at a very short distance in water solution (few micrometers). The ligand is labelled with a radioactive atom and its potential partner is fixed to fluorophore containing beads, the emitted fluorescence proving their interaction can be measured in a scintillation counter. The scintillator measures only the amount of bound radiolabelled ligand. Competition experiment with cold competitor can be done to estimate the binding affinities (50% inhibitory concentration [IC50], cold ligand versus labelled ligand). Loss of signal can also be used to measure substrate cleavage by an enzyme, and labelled antibodies used to titrate the degree of modified residue present." [PMID:3866247]
subset: PSI-MI_slim
synonym: "RIA Radio Immuno Assay" EXACT PSI-MI-alternate []
synonym: "SPA" EXACT PSI-MI-alternate []
synonym: "spa" EXACT PSI-MI-short []
is_a: MI:0013 ! biophysical
[Term]
id: MI:0100
name: sequence based phylogenetic profile
def: "Multiple alignments of orthologous sequences in the same species and their corresponding phylogenetic trees are built. Every phylogenetic tree is computed as a matrix of distances between all possible interacting pairs. The covariation of the distance matrices reveals interacting pairs." [PMID:11707606]
subset: PSI-MI_slim
synonym: "sequence phylogeny" EXACT PSI-MI-short []
is_a: MI:0058 ! genome based prediction
is_a: MI:0101 ! sequence based prediction
[Term]
id: MI:0101
name: sequence based prediction
def: "Computational methods based on evolutionary hypothesis, used as criteria to browse sequences and predict interacting pairs." [PMID:14755292]
subset: PSI-MI_slim
synonym: "predict from sequenc" EXACT PSI-MI-short []
is_a: MI:0063 ! interaction prediction
[Term]
id: MI:0102
name: sequence tag identification
def: "This approach leads to protein identification by combining mass measurement and short amino acid sequence information obtained by tandem mass spectrometry. This information is then used to automatically find the best match in a sequence database. A mixture of peptides derived from a protease digestion is analysed by nanoelectrospray LC-MS/MS (Liquid Chromatography Tandem Mass Spectrometer or nanoESI MS/MS) mass spectrometry. Electrospray mass spectrometry cannot be applied to dilute samples and is affected by high salt. As a consequence peptides, normally extracted from acrylamide gels by in situ proteolysis, are desalted and concentrated on a microcolumn followed by elution into a capillary used for nanoelectrospray tandem mass spectrometry. A first mass spectrum (Normal mass spectrum or Q1 mass spectrum) gives information about the masses of all the peptides. Peptides observed in the normal mass spectrum are isolated in turn and dissociated into fragments by collision with gas molecules within the mass spectrometer. Some of the fragments obtained from a peptide constitute a nested set, differing by one amino acid, and the mass difference between them allows assignment of a partial sequence. The masses of the fragments define the position of the partial sequence in the peptide. Together with the cleavage specificity of the protease used to cleave the protein, and mass information such sequence tag provides much higher search specificity to match the a database entry. The procedure is repeated with several peptides from the digest, resulting in multiple identifications of the same protein or identification of several proteins from the peptide mixture. Unknown proteins can easily be identified by using the high specificity of the peptide sequence tag for searches in most sequence databases including EST or genome databases." [PMID:10967324, PMID:11752590, PMID:11805837]
subset: PSI-MI_slim
synonym: "MS/MS" RELATED []
synonym: "sequence tag" EXACT PSI-MI-short []
is_a: MI:0427 ! Identification by mass spectrometry
is_a: MI:0433 ! partial identification of protein sequence
[Term]
id: MI:0103
name: southern blot
def: "A standard procedure to identify DNA fragments containing specific gene sequences. In this procedure i) a genome is fragmented using a restriction enzyme ii) the generated fragments are separated by electrophoresis iii) the fragments are transferred to a membrane iv)the membrane is incubated with a radio labelled probe that hybridises any complementary subsequence." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0080 ! partial DNA sequence identification by hybridization
[Term]
id: MI:0104
name: static light scattering
def: "In static light scattering, the average intensity of scattered light at multiple angles is measured. The data yield information on particle molecular weight, particle size and shape, and particle-particle interactions." [PMID:9013660]
subset: PSI-MI_slim
synonym: "sls" EXACT PSI-MI-short []
is_a: MI:0067 ! light scattering
[Term]
id: MI:0105
name: structure based prediction
def: "Methods based on 3D structure information." [PMID:14755292]
subset: PSI-MI_slim
synonym: "predict from struct" EXACT PSI-MI-short []
is_a: MI:0063 ! interaction prediction
[Term]
id: MI:0106
name: surface patches
def: "Surface patches are built using 6 criteria: solvation potential, residue interface propensity, hydrophobicity, planarity, protrusion and accessible surface area. Protein structures having similar patches are likely to have the same interactions." [PMID:9299343]
subset: PSI-MI_slim
is_a: MI:0577 ! feature prediction from structure
[Term]
id: MI:0107
name: surface plasmon resonance
def: "This method measures formation of complex by monitoring changes in the resonance angle of light impinging on a gold surface as a result of changes in the refractive index of the surface. A ligand of interest (small molecule, peptide, protein, sugar, lipid, nucleic acid) is immobilized on a gold surface, and the interacting partner is injected in buffer flow over it. Biomolecules that interact with the immobilized ligand are retained on the surface, and alter the resonance angle of impinging light as a result of the change in refractive index brought about by the increased biomolecule mass retained on the surface. Since all the biomolecules belonging to the same class have the same refractive index and since there is a linear correlation between resonance angle shift and biomolecule concentration near the surface, this allows one to measure changes in concentration at the surface as a consequence of interaction. Furthermore, this is done in real time, allowing direct measurement of both the on-rate and the off-rate and of the affinity constant of complex formation." [PMID:11896282, PMID:12120258, PMID:16338355]
subset: PSI-MI_slim
synonym: "BIAcore(r)" EXACT PSI-MI-alternate []
synonym: "Optical biosensor" EXACT PSI-MI-alternate []
synonym: "spr" EXACT PSI-MI-short []
is_a: MI:0659 ! experimental feature detection
is_a: MI:0968 ! biosensor
[Term]
id: MI:0108
name: t7 phage display
def: "T7 is a double stranded DNA bacteriophage with a thin-walled icosahedral capsid, ~550 Angstrom in diameter, which is decorated by 415 copies of the capsid protein, the product of gene 10. gp10 can tolerate insertions at the carboxyterminus without loosing its ability to be inserted into functional phage capsids. Both low density and high density display (albeit only with short peptides) can be achieved." [PMID:14755292]
comment: Reference not index in medline: Rosenberg, A, Griffin, K, Studier, WS, McCormick, M, Berg, J, Novy, R, Mierendorf, R inNovations, 1996, 6, 1.
subset: PSI-MI_slim
synonym: "t7 phage" EXACT PSI-MI-short []
is_a: MI:0084 ! phage display
[Term]
id: MI:0109
name: tap tag coimmunoprecipitation
def: "The TAP method involves the fusion of the TAP tag (encoding a calmodulin binding peptide, a TEV cleavage site, and the Staphylococcus aureus Protein A) to the target protein and the introduction of the construct into the host cell or organism, maintaining the expression of the fusion protein at, or close to, its natural level. The fusion protein and associated components are recovered from cell extracts by affinity selection on an IgG matrix. After washing, the TEV protease is added to release the bound material. The eluate is incubated with calmodulin-coated beads in the presence of calcium. This second affinity step is required to remove the TEV protease as well as traces of contaminants remaining after the first affinity selection. After washing, the bound material is released with EGTA. This two steps purification steps ensures a highly selective complex purification of the tapped protein (first round of selection on the protein A, a high affinity tag) under mild condition (non denaturant pH or conditions required to remove the tag).\nOBSOLETE redundant term. Map to feature type: tap tagged (MI:0524) and as interaction detection method tandem affinity purification (MI:0676)." [PMID:10504710]
subset: PSI-MI_slim
synonym: "tap tag coip" EXACT PSI-MI-short []
is_obsolete: true
[Term]
id: MI:0110
name: text mining
def: "Text mining methods can be used to predict or confirm interactions by automated processing of scientific literature. Co-occurrence in the same sentence of an abstract of gene products labels are analysed to evaluate whether it represents a valid evidence of an interaction." [PMID:14755292]
subset: PSI-MI_slim
is_a: MI:0046 ! experimental knowledge based
[Term]
id: MI:0111
name: dihydrofolate reductase reconstruction
def: "The gene for DHFR is rationally dissected into two fragments called F[1,2] and F[3]. Two proteins or protein domains that are thought to bind to each other can then be fused to either of the two DHFR fragments. Reconstitution of enzyme activity can be monitored in vivo by cell survival in DHFR-negative cells grown in the absence of nucleotides. A fluorescence assay can also be carried out taking advantage of fMTX binding to reconstituted DHFR. The basis of this assay is that complementary fragments of DHFR, when expressed and reassembled in cells, will bind with high affinity (Kd 5 540 pM) to fMTX in a 1:1 complex. fMTX is retained in cells by this complex, whereas the unbound fMTX is actively and rapidly transported out of the cells. Survival depends only on the number of molecules of DHFR reassembled." [PMID:10318894]
subset: PSI-MI_slim
synonym: "dhfr reconstruction" EXACT PSI-MI-short []
is_a: MI:0090 ! protein complementation assay
[Term]
id: MI:0112
name: ubiquitin reconstruction
def: "The split-ubiquitin system provides a method for examining the interactions of membrane proteins. In the split-ubiquitin system, two integral membrane proteins to be studied are fused to two different ubiquitin moieties: a C-terminal ubiquitin moiety (\"Cub\", residues 35-76) and an N-terminal ubiquitin moiety (\"Nub\", residues 1-34). These fused proteins are called the bait and prey, respectively. In addition to being fused to an integral membrane protein, the Cub moiety is also fused to a transcription factor that can be cleaved off by ubiquitin specific proteases. Upon bait-prey interaction, Nub and Cub-moieties assemble, reconstituting the split-ubiquitin. The reconstituted split-ubiquitin molecule is recognized by ubiquitin specific proteases, which cleave off the reporter protein, allowing it to induce the transcription of reporter genes." [PMID:9560251]
subset: PSI-MI_slim
synonym: "membrane yeast two-hybrid" RELATED []
synonym: "myth" RELATED []
synonym: "split-ubiquitin" RELATED []
synonym: "ub reconstruction" EXACT PSI-MI-short []
is_a: MI:1320 ! membrane yeast two hybrid
[Term]
id: MI:0113
name: western blot
def: "Western blot is a procedure to identify and quantify proteins. A mixture of protein is first submitted to an electrophoresis in denaturing condition and then electro-transferred from the gel to a membrane. The membrane is then incubated with a primary antibody specific for a given protein or a specific residue modification in the sample under analysis. A secondary antibody, radiolabelled or fused to fluorophore or to a chromogenic enzyme, targets the first antibody and allows the visualisation of the protein band on the membrane." [PMID:14755292]
subset: PSI-MI_slim
synonym: "Immuno blot" EXACT PSI-MI-alternate []
is_a: MI:0421 ! identification by antibody
is_a: MI:0659 ! experimental feature detection
[Term]
id: MI:0114
name: x-ray crystallography
def: "Analysis of a diffraction pattern generated by a single crystal. X-rays have a wavelength, typically around 1 Angstrom (the diameter of a hydrogen atom). If a narrow parallel beam of X-rays is directed at a sample of a pure protein, most of the X-rays will pass straight through it. A small fraction, however, will be scattered by the atoms in the sample. If the sample is a well-ordered crystal, the scattered waves will reinforce one another at certain points and will appear as diffraction spots when the X-rays are recorded by a suitable detector. The position and intensity of each spot in the X-ray diffraction pattern contain information about the position and nature of the atoms in the crystal. The three-dimensional structure of a large molecule can be deduced from the electron-density map of its crystal. In recent years X-ray diffraction analysis has become increasingly automated, and now the slowest step is likely to be the production of suitable macromolecule crystals. This requires high concentration of very pure macromolecule and empirical searching for the proper crystallization conditions." [PMID:14755292]
subset: PSI-MI_slim
synonym: "co-crystallization" RELATED []
synonym: "co-crystallography" RELATED []
synonym: "X-ray" EXACT PSI-MI-alternate []
synonym: "x-ray diffraction" EXACT PSI-MI-short []
is_a: MI:0013 ! biophysical
is_a: MI:0659 ! experimental feature detection
[Term]
id: MI:0115
name: yeast display
def: "The proteins are displayed on the surface of the yeast S. cerevisiae by fusion to signal sequences for protein secretion. This method is limited by the low efficiency of the yeast display system but can take full advantage of exploiting cell sorting methods (FACS) to isolate cells that display molecules with desired binding properties." [PMID:9181578]