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Correct identification of oxidized histidine residues using electron‐transfer dissociation
Author(s) -
Srikanth Rapole,
Wilson Jonathan,
Vachet Richard W.
Publication year - 2009
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.1552
Subject(s) - chemistry , electron transfer dissociation , histidine , dissociation (chemistry) , peptide , electron transfer , residue (chemistry) , combinatorial chemistry , oxidative phosphorylation , photochemistry , chromatography , mass spectrometry , tandem mass spectrometry , organic chemistry , biochemistry , amino acid
Oxidative modification to the side chain of histidine can noticeably change the collision‐induced dissociation (CID) pathways of peptides containing this oxidized residue. In cases where an oxidized peptide consists two or more isomers differing only in the site of modification, oxidation to histidine usually causes the other oxidized sites to be mis‐assigned in CID spectra. These spectral misassignments can sometimes be avoided by using multiple stages of MS/MS (MS n ) or via specially optimized liquid chromatographic separation conditions. In this manuscript, we demonstrate that these misassignments can be more readily and easily avoided by using electron‐transfer dissociation (ETD) to dissociate the oxidized peptides. Furthermore, we find that the relative insensitivity of ETD to side‐chain chemistry allows the extent of oxidative modification to be determined readily for peptide isomers having more than one site of oxidation. The current results along with previous studies of oxidized peptides suggest that ETD is probably a better technique than CID for obtaining correct sequence and modification information for oxidized peptides. Copyright © 2009 John Wiley & Sons, Ltd.