Molecular packing in 1-hexanol-DMPC bilayers studied by molecular dynamics simulation

U.R. Pedersen; Günther H.j. Peters; P. Westh

doi:10.1016/j.bpc.2006.07.005

Molecular packing in 1-hexanol-DMPC bilayers studied by molecular dynamics simulation

Authors:

Pedersen, U.R. ;
Close
Roskilde University
Peters, Günther H.j. ;
Close
0000-0001-9754-2663
Department of Chemistry, Technical University of Denmark
Westh, P.
Close
Roskilde University

DOI:

10.1016/j.bpc.2006.07.005

Abstract:

The structure and molecular packing density of a “mismatched” solute, 1-hexanol, in lipid membranes of dimyristoyl phosphatidylcholine (DMPC) was studied by molecular dynamics simulations. We found that the average location and orientation of the hexanol molecules matched earlier experimental data on comparable systems. The local density or molecular packing in DMPC–hexanol was elucidated through the average Voronoi volumes of all heavy (non-hydrogen) atoms. Analogous analysis was conducted on trajectories from simulations of pure 1-hexanol and pure (hydrated) DMPC bilayers. The results suggested a positive volume change, ΔVm, of 4 cm3 mol−1 hexanol partitioned at 310 K in good accordance with experimental values. Analysis of the apparent volumes of each component in the pure and mixed states further showed that ΔVm reflects a balance between a substantial increase in the packing density of the alcohol upon partitioning and an even stronger loosening in the packing of the lipid. Furthermore, analysis of Voronoi volumes along the membrane normal identifies a distinctive depth dependence of the changes in molecular packing. The outer (interfacial) part of the lipid acyl chains (up to C8) is stretched by about 4%. Concomitantly, the average lateral area per chain decreases and these two effects compensate so that the overall packing density in the outer region, where the hexanol molecules are located, remains practically constant. The core of the bilayer (C9–C13) is slightly thinned. The average lateral area per chain in this region expands, resulting in a looser packing density. The net effect in the core is a 2–3% decrease in density corresponding to a total volume increase of ∼ 14 cm3 mol−1 hexanol partitioned.

Type:

Journal article

Language:

English

Published in:

Biophysical Chemistry, 2007, Vol 125, Issue 1, p. 104-111

Keywords:

Volume change; Packing density; Lipid membrane; Mismatch; Membrane–solute interaction

Main Research Area:

Science/technology

Publication Status:

Published

Review type:

Peer Review

Submission year:

2007

Scientific Level:

Scientific

ID:

33856346

Molecular packing in 1-hexanol-DMPC bilayers studied by molecular dynamics simulation

Full text access

On-site access

At institutions

Example	Finds records
water{}	containing the word "water".
water supplies"{}"	containing the phrase "water supplies".
author:"Doe, John"author:"{}"	containing the phrase "Doe, John" in the author field.
title:IEEEtitle:{}	containing the word "IEEE" in the title field.
bech{}	containing the word "bech".
marie bech"{}"	containing the phrase "marie bech".
orcid:0000-0002-5429-5292orcid:{}	Having a particular ORCID
Need more help?	Advanced search tutorial