natural, non-standard encoded residue L-pyrrolysine residue (2S)-2-amino-6-[(2R,3R)-3-methyl-3,4-dihydro-2H-pyrrol-2-ylcarbonyl]aminohexanoic acid 0.0 0.0 2-azanyl-6-[(2R,3R)-3-methyl-3,4-dihydro-2H-pyrrol-2-ylcarbonyl]azanylhexanoic acid 237.1477203369140625 237.3000030517578125 A protein modification that inserts or replaces a residue with an L-pyrrolysine residue, a natural pretranslational modification. C 0 H 0 N 0 O 0 C 12 H 19 N 3 O 2 L-pyrrolysine MOD:01187 N6-(4-methyl-1,2-didehydropyrrolidine-5-carboxyl)-L-lysine N6-(4-methyl-delta-1-pyrroline-5-carboxyl)-L-lysine N6-([(2R,3R)-3-methyl-3,4-dihydro-2H-pyrrol-2-yl]carbonyl)-L-lysine NON_STD Pyrrolysine O PSI-MOD Pyl Unimod:435 monomethylamine methyltransferase cofactor lysine adduct natural