Gas-Phase Ion/Ion Chemistry as a Probe for the Presence of Carboxylate Groups in Polypeptide Cations.

ABSTRACT: The reactivity of 1-hydroxybenzoyl triazole (HOBt) esters with the carboxylate functionality present in peptides is demonstrated in the gas phase with a doubly deprotonated dianion. The reaction forms an anhydride linkage at the carboxylate site. Upon ion trap collisional-induced dissociation (CID) of the modified peptide, the resulting spectrum shows a nominal loss of the mass of the reagent and a water molecule. Analogous phenomenology was also noted for model peptide cations that likely contain zwitterionic/salt-bridged motifs in reactions with a negatively charged HOBt ester. Control experiments indicate that a carboxylate group is the likely reactive site, rather than other possible nucleophilic sites present in the peptide. These observations suggest that HOBt ester chemistry may be

SUBMITTER: Pitts-McCoy AM 

PROVIDER: S-EPMC6347497 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature