Effect of cholesterol on structural and mechanical properties of membranes depends on lipid chain saturation

Journal Article · Sat Aug 15 00:00:00 EDT 2009 · Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics (Print)

DOI:https://doi.org/10.1103/PHYSREVE.80.021931· OSTI ID:21344689

Jianjun, Pan; Tristram-Nagle, Stephanie ^[1]; Nagle, John F ^[1]

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1. Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

The effects of cholesterol on membrane bending modulus K{sub C}, membrane thickness D{sub HH}, the partial and apparent areas of cholesterol and lipid, and the order parameter S{sub xray} are shown to depend upon the number of saturated hydrocarbon chains in the lipid molecules. Particularly striking is the result that up to 40% cholesterol does not increase the bending modulus K{sub C} of membranes composed of phosphatidylcholine lipids with two cis monounsaturated chains, although it does have the expected stiffening effect on membranes composed of lipids with two saturated chains. The B fluctuational modulus in the smectic liquid crystal theory is obtained and used to discuss the interactions between bilayers. Our K{sub C} results motivate a theory of elastic moduli in the high cholesterol limit and they challenge the relevance of universality concepts. Although most of our results were obtained at 30 deg. C, additional data at other temperatures to allow consideration of a reduced temperature variable do not support universality for the effect of cholesterol on all lipid bilayers. If the concept of universality is to be valid, different numbers of saturated chains must be considered to create different universality classes. The above experimental results were obtained from analysis of x-ray scattering in the low angle and wide angle regions.

• OSTI ID: 21344689
• Journal Information: Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics (Print), Vol. 80, Issue 2; Other Information: DOI: 10.1103/PhysRevE.80.021931; (c) 2009 The American Physical Society; ISSN 1539-3755
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BIOPHYSICS
CHOLESTEROL
HYDROCARBONS
LAYERS
LECITHINS
LIQUID CRYSTALS
MECHANICAL PROPERTIES
MEMBRANES
ORDER PARAMETERS
SATURATION
X-RAY DIFFRACTION
COHERENT SCATTERING
CRYSTALS
DIFFRACTION
DIMENSIONLESS NUMBERS
ESTERS
FLUIDS
HYDROXY COMPOUNDS
LIPIDS
LIQUIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHOLIPIDS
PHYSICS
SCATTERING
STEROIDS
STEROLS