Glycan motif

[lonelu]

Currently in MetaMorpheus, the N-Glycan motif is 'Nxt, Nxs', where x represents any amino acid.
The 'x' cannot be proline for N-Glycan.
I haven't found which character people used to represents 'Any amino acid except proline'. I noticed 'J' is used for N-Glycan somewhere.

[trishorts]

What about glycine?

[rmillikin]

maybe we can develop some kind of modification motif syntax, like @bintiibrahim did for protease cleavage specificity?
So like X{P} means any amino acid except P

[lonelu]

What about glycine?

Glycine should be fine for N-Glycan as far as I know.