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A study of non-covalent complexes between peptides containing multiple binding sites using HCD and ETD

Friday, November 08, 2013 — Poster Session IV

2:00 p.m. – 4:00 p.m.

FAES Academic Center (Upper-Level Terrace)




  • LM Muller
  • LT Rodrigues
  • SN Jackson
  • A Roux
  • AS Woods


Electrostatic interactions play a key role in the formation of non-covalent complexes (NCX). Our previous work has highlighted the role of certain amino acid residues in the formation of NCX between peptides. NCX can form between two or more adjacent arginines RR or RKR on one epitope (basic epitope) and two or more adjacent glutamate/aspartate or one phosphorylated/sulfated residue on the other epitope (acidic epitope). Tandem ESI-MS experiments were conducted on NCX between peptides containing multiple binding site using HCD and ETD.HCD experiments allowed us to determine the relative strength of the electrostatic interaction, the ETD experiment indicated the more favorable sites. Initial MS analysis showed that all epitopes mixtures readily produced multicharged NCX ions. HCD experiments were conducted to evaluate the NCX stability and show different fragmentation pathways according to the two epitotes studied. Formation, fragmentation and stability/disassociation curve have been recorded for each NCX and show, first, that the phosphorylation and secondly the increasing number of sites in one epitote allow a stronger interaction. ETD experiments were conducted to determine which of these sites of interaction are preferential for NCX formation in each peptide.

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