title: Size-exclusion high-performance liquid chromatography in the study of the autoassociating antibiotic gramicidin A in micellar milieu.
abstract: Gramicidin A (gA) is a polypeptide antibiotic which forms dimeric channels specific for monovalent cations in biological membranes. It is a polymorphic molecule that adopts several different conformations, double-stranded (ds) helical dimers (pore conformation) and single-stranded beta-helical dimers (channel conformation). This study investigated the conformational adaptability of gramicidin A when incorporated into micelles as membrane-mimetic model system. Taking advantage of our reported, versatile, size-exclusion high-performance liquid chromatography (SE-HPLC) strategy that allows the separation of double-stranded dimers and monomers, we have quantitatively characterized the conformational transition undergone by the peptide in the micellar milieu. The importance of both hydrophobic/hydrophilic moieties of the amphipaths in the stabilization of concrete conformational species is demonstrated using detergents with different hydrocarbon chain length and/or polar head. SE-HPLC is a valuable, rapid, accurate technique for the structural characterization of hydrophobic autoassociating peptides that work in lipid environments such as biological membranes.
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Universitat de València, C/ Doctor Moliner 50, E-46100 Burjassot, Valencia, Spain.
authors.forename: Maria Carmen
authors.initials: MC
authors.lastname: Bañó
authors.forename: David
authors.initials: D
authors.lastname: Salom
authors.forename: Concepción
authors.initials: C
authors.lastname: Abad
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis / Q000737:chemistry; D040761:Biomimetic Materials / Q000032:analysis* / Q000737:chemistry*; D002850:Chromatography, Gel / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002942:Circular Dichroism; D003102:Colloids / Q000032:analysis / Q000737:chemistry; D019281:Dimerization; D006096:Gramicidin / Q000032:analysis* / Q000737:chemistry*; D008563:Membrane Lipids / Q000032:analysis / Q000737:chemistry*; D008567:Membranes, Artificial; D008823:Micelles; D011487:Protein Conformation; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D003102:Colloids; D008563:Membrane Lipids; D008567:Membranes, Artificial; D008823:Micelles; D013501:Surface-Active Agents; D006096:Gramicidin