Characterization of acetylated histidine b₁-ion structure: A competition between oxazolone and side chain imidazole moiety

Abstract

The detection of post-translational modifications of proteins is an important comprehensive research area. Over the years, proteomic studies involving protein acetylation have attracted a great deal of attention. In the present study, we have focussed on the acetylation of histidine and the intrinsic stability of b-ion of oxazolone ring and/or with side chain imidazole bicyclic product. The formation of oxazolone structure may occur when an amino moiety undergoes acetylation reaction and when it is present in the vicinity of the side chain imidazole moiety. Tryptic peptides generated from the proteins of Acenitobacter radioresistens MMC5-containing N-terminal histidine were explored in a standard proteomic workflow. Formation of [Formula: see text] ion with an oxazolone ring in these peptides has been supported by a tandem mass spectrometric study of a synthetic peptide and density functional theory calculations. The results obtained from this study have implications in understanding the fragmentation of the peptides generated in the proteomic workflows.

Mass spectral analysis of acetylated peptides: Implications in proteomics

“…8 Studies in our laboratory revealed that acetylation of N-terminal histidine-containing peptides leads to the formation of a b 1 ion with an oxazolone structure. 11 Thus, acetylation of peptides generated by trypsin digestion of proteins helps in determining the primary structure of the peptides.…”