Covalent and non-covalent dissociations of gas-phase complexes of avoparcin and bacterial receptor mimicking precursor peptides studied by collisionally activated decomposition mass spectrometry

✍ Scribed by van der Kerk-van Hoof, Anca; Heck, Albert J. R.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 100 KB
• Volume: 34
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/(sici)1096-9888(199908)34:8<813::aid-jms836>3.0.co;2-7

✦ Synopsis

The gas-phase stability and reactivity of non-covalent complexes of avoparcin and bacterial receptor mimicking precursor peptides were probed by electrospray ionization mass spectrometry combined with collisionally activated decomposition (CAD) studies. The order of the gas-phase stabilities of these non-covalent complexes is different from the order of the stabilities of the same complexes in solution. The specific stereoselectivity observed in non-covalent binding in solution is not retained in the gas phase. The presence of a lysine residue in the bacterial receptor mimicking precursor peptides appears to promote the gas-phase stabilities of the antibiotic-peptide complexes. Complexes of avoparcin with receptor peptides containing a lysine residue are stabilized in the gas phase to such an extent that CAD of these non-covalent complexes proceeds through a competition between non-covalent and covalent fragmentation pathways. These results indicate clearly that the use of CAD mass spectra for the quantitative characterization of the stability of non-covalent complexes in solution should be applied with extreme caution.