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Combined Electron Transfer Dissociation-Collision-Induced Dissociation Fragmentation in the Mass Spectrometric Distinction of Leucine, Isoleucine, and Hydroxyproline Residues in Peptide Natural Products

Gupta, Kallol and Kumar, Mukesh and Chandrashekara, Krishnappa and Krishnan, Kozhalmannom S and Balaram, Padmanabhan (2012) Combined Electron Transfer Dissociation-Collision-Induced Dissociation Fragmentation in the Mass Spectrometric Distinction of Leucine, Isoleucine, and Hydroxyproline Residues in Peptide Natural Products. In: Journal of Proteome Research, 11 (2). pp. 515-522.

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Official URL: http://pubs.acs.org/doi/abs/10.1021/pr200091v

Abstract

Distinctions between isobaric residues have been a major challenge in mass spectrometric peptide sequencing. Here, we propose a methodology for distinction among isobaric leucine, isoleucine, and hydroxyproline, a commonly found post-translationally modified amino acid with a nominal mass of 113 Da, through a combined electron transfer dissociation-collision-induced dissociation approach. While the absence of c and z(center dot) ions, corresponding to the Yyy-Xxx (Xxx = Leu, Ile, or Hyp) segment, is indicative of the presence of hydroxyproline, loss of isopropyl (Delta m = 43 Da) or ethyl radicals (Delta m = 29 Da), through collisional activation of z(center dot) radical ions, are characteristic of leucine or isoleucine, respectively. Radical migration processes permit distinctions even in cases where the specific e ions, corresponding to the Yyy-Leu or -Ile segments, are absent or of low intensity. This tandem mass spectrometric (MSn) method has been successfully implemented in a liquid chromatography MSn platform to determine the identity of 23 different isobaric residues from a mixture of five different peptides. The approach is convenient for distinction of isobaric residues from any crude peptide mixture, typically encountered in natural peptide libraries or proteomic analysis.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to
Keywords: isobaric amino acids;electron transfer dissociation;z(center dot) ions;collision-induced dissociation;peptaibols;Conus peptides;wasp venom peptides
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited: 04 Apr 2012 12:18
Last Modified: 04 Apr 2012 12:18
URI: http://eprints.iisc.ernet.in/id/eprint/44174

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