Tyrosine deprotonation yields abundant and selective backbone cleavage in peptide anions upon negative electron transfer dissociation and ultraviolet photodissociation.

ABSTRACT: Tyrosine deprotonation in peptides yields preferential electron detachment upon NETD or UVPD, resulting in prominent N-Cα bond cleavage N-terminal to the tyrosine residue. UVPD of iodo-tyrosine-modified peptides was used to generate localized radicals on neutral tyrosine side chains by homolytic cleavage of the C-I bond. Subsequent collisional activation of the radical species yielded the same preferential cleavage of the adjacent N-terminal N-Cα bond. LC-MS/MS analysis of a tryptic digest of BSA demonstrated that these cleavages are regularly observed for peptides when using high-pH mobile phases.

SUBMITTER: Shaw JB 

PROVIDER: S-EPMC3459303 | biostudies-literature | 2012 Sep

REPOSITORIES: biostudies-literature