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Conformation of gramicidin a in water: Inference from analysis of hydrogen/deuterium exchange behavior by matrix assisted laser desorption ionization mass spectrometry
Author(s) -
Jagannadham M. V.,
Nagaraj Ramakrishnan
Publication year - 2005
Publication title -
peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.20293
Subject(s) - chemistry , gramicidin , hydrogen–deuterium exchange , gramicidin s , desorption , mass spectrometry , monomer , deuterium , solvent , ionization , solubility , analytical chemistry (journal) , ion , chromatography , membrane , organic chemistry , adsorption , polymer , physics , biochemistry , quantum mechanics
Gramicidin A (the major component of gramicidin D) is a highly hydrophobic peptide with very little solubility in water. Hence, the conformation of this peptide has been extensively investigated in organic solvents and model membranes, but not in water. The peptide adopts a β 6.3 ‐helical conformation in the monomeric and dimeric forms. We have investigated the conformation of gramicidin A in water by monitoring hydrogen–deuterium exchange by matrix‐assisted laser desorption ionization–time‐of‐flight mass spectrometry. Our results indicate that gramicidin A is monomeric and exists in a highly folded conformation. The metal ion bound forms are clearly discernible in the monomers. The presence of the dimeric form is not observed. It is unlikely this is due to the operating conditions or the method used, as both hetero‐ and homodimers in gramicidin D are detected when methanol is used as a solvent. The present study also establishes that the linear gramicidins retain a history of solvent environment when ions are generated by matrix‐assisted laser desorption ionization and analyzed by time‐of‐flight. © 2005 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 80: 708–713, 2005 This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com