Identifying N15-labelled spiked-in protein

[vladpetyuk]

Hello,
I have a sample with one spiked-in protein. This protein is N15 metabolically-labeled. The identification of the endogenous N14 component went well. To catch the N15 protein I decided to do fixed modification search (since having 20 dynamic mods most likely would be computationally taxing) with the following additional options:

--fixed-mod N15:1,0.997035,GASPVTLIDEMFY
--fixed-mod N15:2,1.99407,NQKW
--fixed-mod N15:3,2.991105,H
--fixed-mod N15:4,3.98814,R
--fixed-mod N15:1C,58.01854,C

I tried it both ways - 1) using DNN pre-generated spectral library and 2) providing just the FASTA file and checking the box to generate the library with the DNN. In either case the results were empty.
Any tips how to do the search for N15 isotopically-labeled protein will be appreciated,
Vlad

[vladpetyuk]

topic 542 might be relevant.

[vladpetyuk]

Seems like those settings did the trick. Kudos to @FarmGeek4Life and @DavidRossHall for helping out!

--fixed-mod N15,0.0,GASPVTCLINDQKEMHFRYW,label
--lib-fixed-mod N15
--channels N15,L,GASPVTCLINDQKEMHFRYW,0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0; N15,H,GASPVTCLINDQKEMHFRYW,0.997035:0.997035:0.997035:0.997035:0.997035:0.997035:0.997035:0.997035:0.997035:1.99407:0.997035:1.99407:1.99407:0.997035:0.997035:2.991105:0.997035:3.98814:0.997035:1.99407
--peak-translation
--original-mods