oxazole/oxazoline ring crosslinked residues (Ser) L-isoleucine oxazole-4-carboxylic acid -20.026214599609375 -20.030000686645507812 180.089874267578125 180.2100067138671875 2-[(1S,2S)-1-amino-2-methylbutyl]-1,3-oxazole-4-carboxylic acid 2-[(1S,2S)-1-azanyl-2-methylbutyl]-1,3-oxazole-4-carboxylic acid A protein modification that effectively crosslinks an L-isoleucine residue and an L-serine residue to form L-cysteine oxazole-4-carboxylic acid. C 0 H -4 N 0 O -1 C 9 H 12 N 2 O 2 CROSSLNK Oxazole-4-carboxylic acid (Ile-Ser) Cross-link 2. I, S L-isoleucine oxazole-4-carboxylic acid MOD:01902 PSI-MOD natural uniprot.ptm:PTM-0463 crosslinked L-isoleucine residue didehydrogenated and dehydrated residue