L-beta-methylthioaspartic acid 161.0146636962890625 161.17999267578125 45.987720489501953125 46.090000152587890625 beta-Methylthio-aspartic acid 3-(methylthio)-L-aspartic acid methythiold MOD_RES 3-methylthioaspartic acid beta-methylthio-aspartic acid Beta-methylthiolation natural D (2R,3Xi)-2-amino-3-(methylsulfanyl)butanedioic acid bmethylthiold C 5 H 7 N 1 O 3 S 1 3-methylthio-aspartic acid MOD:00237 Methylthio 3MeSAsp A protein modification that effectively converts an L-aspartic acid residue to L-beta-methylthioaspartic acid. PSI-MOD 3-carboxy-S-methyl-cysteine none C 1 H 2 S 1 modified L-aspartic acid residue methylthiolated residue