Spin label EPR studies of the effect of gramicidin S on lipid chain dynamics

M. Kiricsi, L. I. Horváth, L. Dux, T. Páli

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The effect of gramicidin S (GS) on acyl chain dynamics of 14-doxylstearic acid spin label (14-SASL) monitoring the centre of dimyristoylphosphatidylcholine (DMPC) bilayers was studied with electron paramagnetic resonance (EPR) spectroscopy. The Chain-melting transition of DMPC was shifted down and broadened monotonously by several degrees with increasing peptide concentration in the range of lipid/peptide ratios of 1/p=5/1-15/1. The effective rotational correlation time τeff of 14-SASL became larger with increasing amounts of peptide bound to fluid membranes of DMPC. From the dependence of τeff on the lipid/peptide molar ratio it was estimated that about 10 DMPC molecules per monomer GS are involved in non-covalent peptide-lipid interaction. Optimized spectral subtractions showed that, well above the chain-melting transition, 90% of the EPR spectral intensity of the spin-labeled peptide-lipid complex (1/p=5/1) originated from spectra recorded in bilayers (without peptide) at lower temperature. This was not the case 6°C above the phase transition where two components with comparable intensities were detected. The two components were identified as different motional modes of the label molecules, rather than distinct mobile/immobile lipid populations.

Original languageEnglish
Pages (from-to)469-475
Number of pages7
JournalJournal of Molecular Structure
Volume563-564
DOIs
Publication statusPublished - May 28 2001

Fingerprint

Gramicidin
Spin Labels
Electron Spin Resonance Spectroscopy
peptides
Paramagnetic resonance
lipids
electron paramagnetic resonance
Dimyristoylphosphatidylcholine
Lipids
Peptides
Freezing
Melting
melting
acids
Molecules
Phase Transition
subtraction
Labels
molecules
Spectrum Analysis

Keywords

  • Antibiotics
  • Gramicidin S
  • Lipid chain dynamics
  • Peptide-lipid interaction
  • Spin label electron paramagnetic resonance

ASJC Scopus subject areas

  • Structural Biology
  • Organic Chemistry
  • Physical and Theoretical Chemistry
  • Spectroscopy
  • Atomic and Molecular Physics, and Optics

Cite this

Spin label EPR studies of the effect of gramicidin S on lipid chain dynamics. / Kiricsi, M.; Horváth, L. I.; Dux, L.; Páli, T.

In: Journal of Molecular Structure, Vol. 563-564, 28.05.2001, p. 469-475.

Research output: Contribution to journalArticle

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