Variable modifications greyed out

[B@rtenB]

Dear all,

I'm running peaks 4.5SP2.

This morning I attempted a spider search in a protein database.
my data are comming from tryptic digest cutted 2D gel spots (whats in
the word :D).
So I have to set carbamidomethylation as fixed, and normally for
proteinID I also put oxidation, sulfatation and phosphorylation,
amidation as variable. but in the spider search I can't set variable
modifications.

Now when I let the program run, it gives an error saying it detected a
PTM, but it is not specified in fixed or variable (I Can't!!!) PTMS,
so the PTM is ignored.

is this normal? What's the purpose of the disabled variable PTM tab?

happy holidays and merry christmas!

Bart

[yorki...@hotmail.com]

Bart,

Unfortunately with PEAKS Studio 4.5 sp 2, they didn't offer variable
modification support within Spider.
The good news is the current versions (5.1) does support this search
through 'Homology Match' mode.

I'm not really sure why its only Homology Match mode only, but it
probably has something to do with it being the most intensive mode
within the Spider methods.

Hope that helps.
David.