An application of electrospray ionization tandem mass spectrometry to probe the interaction of Ca2+/Mg2+/Zn2+ and Cl− with gramicidin A
Article first published online: 9 MAY 2005
Copyright © 2005 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 19, Issue 11, pages 1517–1521, 15 June 2005
How to Cite
Sudhir, P.-R., Wu, H.-F. and Zhou, Z.-C. (2005), An application of electrospray ionization tandem mass spectrometry to probe the interaction of Ca2+/Mg2+/Zn2+ and Cl− with gramicidin A. Rapid Commun. Mass Spectrom., 19: 1517–1521. doi: 10.1002/rcm.1947
- Issue published online: 11 MAY 2005
- Article first published online: 9 MAY 2005
- Manuscript Revised: 24 MAR 2005
- Manuscript Accepted: 24 MAR 2005
- Manuscript Received: 31 JAN 2005
- National Science Council of Taiwan and Department of Chemistry, Tamkang University
The peptide, gramicidin A (GrA), has been demonstrated to interact with divalent salts (CaCl2, MgCl2, and ZnCl2) using electrospray ionization mass spectrometry (ESI-MS). The ESI-MS analysis revealed different complexes formed due to the interaction of Val-GrA and Ile-GrA with divalent salts: [Val or Ile-GrA-H+M]+, [Val or Ile-GrA+MCl]+ and [Val or Ile-GrA+M]2+, where M is Ca or Mg or Zn. All these complexes have been subjected to collisionally activated dissociation (CAD). CAD of singly and doubly charged GrA and metal complexes exhibited the losses of water molecules, indicating the ligand preference of GrA. MS/MS and MS3 of [Val or Ile-GrA+MCl]+ resulted in the elimination of chloride ion and water, respectively. The tandem mass spectrometry data of the complex [Val-GrA+MCl]+ suggest that chloride interaction is stronger in the presence of Ca than of Mg and Zn. This study reveals that GrA could interact with Ca, Mg, and Zn in metal ion form as well as in ion pair (MCl) form. The interactions of GrA with Ca support the proposal of a physical basis for the messenger role of Ca (Urry et al., J. Biol. Chem. 1982, 257: 6659–6661). Copyright © 2005 John Wiley & Sons, Ltd.