Volume 111, 1999

Lipid–protein interactions in the membrane: Studies with model peptides

Abstract

We have used fluorescence quenching of tryptophan-containing trans-membrane peptides by bromine-containing phospholipids to study the specificity of peptide–lipid interactions. We have synthesized peptides Ac-K2GLmWLnK2A-amide where m=7 and n=9 (L16) and m=10 and n=12 (L22). Binding constants of L22 for dioleoylphosphatidylserine [di(C18:1)PS] or dioleoylphosphatidic acid [di(C18:1)PA] relative to dieoleoylphosphatidylcholine [di(C18:1)PC] were close to 1. However, for L16, whilst the bulk of the di(C18:1)PA molecules bound with a binding constant relative to di(C18:1)PC close to 1, a small number of di(C18:1)PA molecules bound much more strongly. Assuming just one high affinity binding site on L16 for anionic lipid, the affinity of the site for di(C18:1)PS was calculated to be ca. 8 times that for di(C18:1)PC. The relative binding constant was little affected by ionic strength and close contact between the anionic headgroup of di(C18:1)PS and a lysine residue on the peptide was suggested. The relative binding constant for di(C18:1)PS at this high affinity site was less than for di(C18:1)PA. Cholesterol interacts with L22 with an affinity about 0.7 of that of di(C18:1)PC. The structure of the peptide itself is important. The peptide Ac-KKGYL6WL8YKKA-amide (Y2L14) incorporated into bilayers of dinervonylphosphatidylcholine [di(C24:1)PC] whereas L16 did not incorporate into this lipid. It is suggested that thinning of a lipid bilayer around a peptide to give optimal hydrophobic matching is less energetically unfavourable when a Tyr residue is located in the lipid/water interfacial region.

Article information

Article type
Paper

Faraday Discuss., 1999,111, 127-136

Lipid–protein interactions in the membrane: Studies with model peptides

S. Mall, R. P. Sharma, J. Malcolm East and A. G. Lee, Faraday Discuss., 1999, 111, 127 DOI: 10.1039/A809299K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements