Sterol evolution and the physics of membranes

M. Nielsen ¹ - J. Thewalt ² - L. Miao ^1,3 - J. H. Ipsen ¹ - M. Bloom ⁴ -
M. J. Zuckermann ² - O. G. Mouritsen ¹

 ¹ MEMPHYS, Department of Chemistry, Technical University of Denmark
Building 206, DK-2800 Lyngby, Denmark
 ² Department of Physics, Simon Fraser University - Vancouver, V5A 1S6 Canada
 ³ Department of Physics, University of Southern Denmark
Campusvej 55, DK-5320 Odense M, Denmark
 ⁴ Department of Physics and Astronomy, University of British Columbia
Vancouver, V6T 1W5 Canada

PACS :
87.16.Dg - Membranes, bilayers, and vesicles
87.14.Cc - Lipids
87.23.-n - Ecology and evolution

ogm@kemi.dtu.dk

Abstract:

Sterols are important molecular components of the plasma membranes of eucaryotic cells. Using deuterium NMR spectroscopy in conjunction with statistical mechanical modelling, we present a unifying picture of how the evolution-engineered differences in molecular chemistry between cholesterol and its precursor lanosterol are manifested in the physical properties of model membranes in terms of molecular order and phase equilibria. Cholesterol optimizes the stability of a particular membrane phase, the liquid-ordered phase, that is a liquid and at the same time exhibits high molecular conformational order.

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