The relative effect of sterols and hopanoids on lipid bilayers: when comparable is not identical

Poger, David and Mark, Alan E. (2013) The relative effect of sterols and hopanoids on lipid bilayers: when comparable is not identical. Journal of Physical Chemistry B, 117 50: 16129-16140. doi:10.1021/jp409748d

Author Poger, David
Mark, Alan E.
Title The relative effect of sterols and hopanoids on lipid bilayers: when comparable is not identical
Journal name Journal of Physical Chemistry B   Check publisher's open access policy
ISSN 1520-6106
Publication date 2013-12-19
Year available 2013
Sub-type Article (original research)
DOI 10.1021/jp409748d
Open Access Status Not yet assessed
Volume 117
Issue 50
Start page 16129
End page 16140
Total pages 12
Place of publication Washington, DC, United States
Publisher American Chemical Society
Language eng
Abstract Sterols are the hallmarks of eukaryotic membranes where they are often found in specialized functional microdomains of the plasma membrane called lipid rafts. Despite some notable exceptions, prokaryotes lack sterols. However, growing evidence has suggested the existence of raft-like domains in the plasma membrane of bacteria. A structurally related family of triterpenoids found in some bacteria called hopanoids has long been assumed to be bacterial surrogates for sterols in membranes. Although the effect of sterols, in particular cholesterol, on lipid bilayers has been extensively characterized through experimental and simulation studies, those of hopanoids have hardly been investigated. In this study, molecular dynamics simulations are used to examine the effect of two hopanoids, diploptene (hop-22(29)-ene) and bacteriohopanetetrol ((32R,33S,34S)-bacteriohopane-32,33,34,35-tetrol), on a model bilayer. The results are compared with those obtained for cholesterol and a pure phosphatidylcholine bilayer. It is shown that diploptene and bacteriohopanetetrol behave very differently under the conditions simulated. Whereas bacteriohopanetetrol adopted a cholesterol-like upright orientation in the bilayer, diploptene partitioned between the two leaflets inside the bilayer. Analysis of various structural properties (area per lipid, electron density profile, tilt angle of the lipids, and conformation and order parameters of the phosphatidylcholine tails) in bacteriohopanetetrol- and cholesterol-containing bilayers indicates that the condensing and ordering effect of bacteriohopanetetrol is weaker than that of cholesterol. The simulations suggest that the chemical diversity of hopanoids may lead to a broader range of functional roles in bacterial membranes than sterols in eukaryotic membranes.
Keyword Chemistry, Physical
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Chemistry and Molecular Biosciences
Institute for Molecular Bioscience - Publications
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Citation counts: TR Web of Science Citation Count  Cited 12 times in Thomson Reuters Web of Science Article | Citations
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