ester crosslinked residues crosslinked residues with loss of water O-(L-isoaspartyl)-L-threonine (cross-link) -18.010564804077148438 -18.020000457763671875 198.064056396484375 198.17999267578125 (2S)-2-amino-4-([(1S,2R)-1-amino-1-carboxypropan-2-yl]oxy)-4-oxobutanoic acid (2S,3R)-2-amino-3-([(4S)-3-amino-3-carboxypropanoyl]oxy)propanoic acid CROSSLNK isoaspartyl threonine ester (Thr-Asp) H -2 O -1 O-(L-isoaspartyl)-L-threonine C 8 H 10 N 2 O 4 natural O3-(isoaspartyl)-threonine O(beta)-(beta-aspartyl)threonine D, T MOD:01947 A protein modification that effectively cross-links an L-threonine residue and an L-aspartic acid residue with an ester bond to form O-(L-isoaspartyl)-L-threonine. none Cross-link 2. PSI-MOD O-(L-isoaspartyl)-L-threonine crosslinked L-aspartic acid residue