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Effective lipid‐detergent system for study of membrane active peptides in fluid liposomes
Author(s) -
Sychev Sergei V.,
Sukhanov Stanislav V.,
Telezhinskaya Iri.,
Ovchinnikova Tatiana V.
Publication year - 2016
Publication title -
journal of peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 66
eISSN - 1099-1387
pISSN - 1075-2617
DOI - 10.1002/psc.2845
Subject(s) - chemistry , liposome , microviscosity , membrane , lipid bilayer , gramicidin , peptide , fluorescence anisotropy , chromatography , phosphatidylcholine , membrane fluidity , turbidimetry , dynamic light scattering , biophysics , analytical chemistry (journal) , biochemistry , phospholipid , chemical engineering , biology , nanoparticle , engineering
The structure of peptide antibiotic gramicidin A (gA) was studied in phosphatidylcholin liposomes modified by nonionic detergent Triton X‐100. First, the detergent : lipid ratio at which the saturation of lipid membrane by Triton X‐100 occurs (R e sat ), was determined by light scattering. Measurements of steady‐state fluorescence anisotropy of 1,6‐diphenyl‐1,3,5‐hexatriene at sublytic concentrations of detergent showed that after saturation of the membrane by Triton X‐100 microviscosity of lipid bilayer is reduced by 20%. The equilibrium conformational state of gA in phosphatidylcholine liposomes at R e sat was studied by CD spectroscopy. It was found that the conformational state of this channel‐forming peptide changed crucially when Triton X‐100 induced transition to more fluid membranes. The gA single‐channel measurements were made with Triton X‐100 containing bilayers. Tentative assignment of the channel type and gA structures was made by correlation of CD data with conductance histograms. Lipid‐detergent system with variable viscosity developed in this work can be used to study the structure and folding of other membrane‐active peptides. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.