derives from 2'-[3-carboxamido-3-(trimethylammonio)propyl]-L-histidine modified L-histidine residue N-tau-(ADP-ribosyl)diphthamide 1+ 684.17901611328125 684.510009765625 821.2379150390625 821.6500244140625 A protein modification that effectively converts an L-histidine residue to N-tau-(ADP-ribosyl)diphthamide. C 22 H 36 N 7 O 14 P 2 C 28 H 43 N 10 O 15 P 2 From DeltaMass: (name misspelled "N theta -(ADP-ribosyl) diphthamide (of Histidine)") Average Mass: 648 H MOD:01145 MOD_RES ADP-ribosyldiphthamide PSI-MOD natural uniprot.ptm:PTM-0672 adenosine diphosphoribosyl (ADP-ribosyl) modified residue