title: 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.
authors.affiliation: Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, United States.
authors.forename: Jared B
authors.initials: JB
authors.lastname: Shaw
authors.forename: Aaron R
authors.initials: AR
authors.lastname: Ledvina
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
authors.forename: Ryan R
authors.initials: RR
authors.lastname: Julian
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Brodbelt
mesh_terms: D000595:Amino Acid Sequence; D000838:Anions; D004583:Electrons; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D055668:Photochemical Processes; D059748:Proteolysis; D011522:Protons; D014443:Tyrosine / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D000838:Anions; D010455:Peptides; D011522:Protons; D014443:Tyrosine