The University of Southampton
University of Southampton Institutional Repository

Effects of aromatic residues at the ends of transmembrane alpha-helices on helix interactions with lipid bilayers

Effects of aromatic residues at the ends of transmembrane alpha-helices on helix interactions with lipid bilayers
Effects of aromatic residues at the ends of transmembrane alpha-helices on helix interactions with lipid bilayers
We have studied the effects of aromatic residues at the ends of peptides of the type Ac-KKGLnWLmKKA-amide on their interactions with lipid bilayers as a function of lipid fatty acyl chain length, physical phase, and charge. Peptide Ac-KKGFL6WL8FKKA-amide (F2L14) incorporated into bilayers of phosphatidylcholines containing monounsaturated fatty acyl chains of lengths C14-C24 at a peptide:lipid molar ratio of 1:100 in contrast to Ac-KKGL7WL9KKA-amide (L16) which did not incorporate at all into dierucoylphosphatidylcholine [di(C24:1)PC]; Ac-KKGYL6WL8YKKA-amide (Y2L14) incorporated partly into di(C24:1)PC. Lipid-binding constants relative to that for dioleoylphosphatidylcholine (C18:1)PC were obtained using a fluorescence quenching method. For Y2L14 and F2L14, relative lipid-binding constants increased with increasing fatty acyl chain length from C14 to C24; strongest binding did not occur at the point where the hydrophobic length of the peptide equalled the hydrophobic thickness of the bilayer. For Ac-KKGYL9WL11YKKA-amide (Y2L20), increasing chain length from C18 to C24 had little effect on relative binding constants. Anionic phospholipids bound more strongly than zwitterionic phospholipids to Y2L14 and Y2L20 but effects of charge were relatively small. In two phase (gel and liquid crystalline) mixtures, all the peptides partitioned more strongly into liquid crystalline than gel phase; effects were independent of the structure of the peptide or of the lipid (dipalmitoylphosphatidylcholine or bovine brain sphingomyelin). Addition of cholesterol had little effect on incorporation of the peptides into lipid bilayers. It is concluded that the presence of aromatic residues at the ends of transmembrane -helices effectively buffers them against changes in bilayer thickness caused either by an increase in the chain length of the phospholipid or by the presence of cholesterol.
0006-2960
2071-2078
Mall, S.
343a3062-0630-4e15-8d55-ebb4288f3a8b
Broadbridge, R.
85df8b86-d1d9-42d3-8764-6aaebab3d856
Sharma, R.P.
aef51420-fc90-49d8-b04c-142214c2961a
Lee, A.G.
0891914c-e0e2-4ee1-b43e-1b70eb072d8e
East, J.M.
9fe7f794-1d89-4935-9a99-b831d786056e
Mall, S.
343a3062-0630-4e15-8d55-ebb4288f3a8b
Broadbridge, R.
85df8b86-d1d9-42d3-8764-6aaebab3d856
Sharma, R.P.
aef51420-fc90-49d8-b04c-142214c2961a
Lee, A.G.
0891914c-e0e2-4ee1-b43e-1b70eb072d8e
East, J.M.
9fe7f794-1d89-4935-9a99-b831d786056e

Mall, S., Broadbridge, R., Sharma, R.P., Lee, A.G. and East, J.M. (2000) Effects of aromatic residues at the ends of transmembrane alpha-helices on helix interactions with lipid bilayers. Biochemistry, 39 (8), 2071-2078. (doi:10.1021/bi992205u).

Record type: Article

Abstract

We have studied the effects of aromatic residues at the ends of peptides of the type Ac-KKGLnWLmKKA-amide on their interactions with lipid bilayers as a function of lipid fatty acyl chain length, physical phase, and charge. Peptide Ac-KKGFL6WL8FKKA-amide (F2L14) incorporated into bilayers of phosphatidylcholines containing monounsaturated fatty acyl chains of lengths C14-C24 at a peptide:lipid molar ratio of 1:100 in contrast to Ac-KKGL7WL9KKA-amide (L16) which did not incorporate at all into dierucoylphosphatidylcholine [di(C24:1)PC]; Ac-KKGYL6WL8YKKA-amide (Y2L14) incorporated partly into di(C24:1)PC. Lipid-binding constants relative to that for dioleoylphosphatidylcholine (C18:1)PC were obtained using a fluorescence quenching method. For Y2L14 and F2L14, relative lipid-binding constants increased with increasing fatty acyl chain length from C14 to C24; strongest binding did not occur at the point where the hydrophobic length of the peptide equalled the hydrophobic thickness of the bilayer. For Ac-KKGYL9WL11YKKA-amide (Y2L20), increasing chain length from C18 to C24 had little effect on relative binding constants. Anionic phospholipids bound more strongly than zwitterionic phospholipids to Y2L14 and Y2L20 but effects of charge were relatively small. In two phase (gel and liquid crystalline) mixtures, all the peptides partitioned more strongly into liquid crystalline than gel phase; effects were independent of the structure of the peptide or of the lipid (dipalmitoylphosphatidylcholine or bovine brain sphingomyelin). Addition of cholesterol had little effect on incorporation of the peptides into lipid bilayers. It is concluded that the presence of aromatic residues at the ends of transmembrane -helices effectively buffers them against changes in bilayer thickness caused either by an increase in the chain length of the phospholipid or by the presence of cholesterol.

This record has no associated files available for download.

More information

Published date: 29 January 2000

Identifiers

Local EPrints ID: 56698
URI: http://eprints.soton.ac.uk/id/eprint/56698
ISSN: 0006-2960
PURE UUID: c031ae00-bd6b-4e50-acb6-eff7b1c0bfa4

Catalogue record

Date deposited: 21 Aug 2008
Last modified: 15 Mar 2024 11:03

Export record

Altmetrics

Contributors

Author: S. Mall
Author: R. Broadbridge
Author: R.P. Sharma
Author: A.G. Lee
Author: J.M. East

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×