Curvature and Lipid Packing Modulate the Elastic Properties of Lipid Assemblies: Comparing HII and Lamellar Phases.
Accumulating evidence indicates that membrane reshaping and fusion processes, as well as regulation of membrane protein function, depend on lipid composition. Although it is widely accepted that cell membranes are under considerable stress and frustration and can be locally highly curved, experimental approaches to determine the material properties of lipids usually rely on their study in a relaxed environment or in flat bilayers. Here, we propose a computational method to determine the elastic properties of lipid assemblies of arbitrarily shaped interfaces and apply it to lipidic mixtures in the inverted hexagonal and lamellar phases. We find that the bending rigidity critically depends on the geometry of the system and correlates with the changes in lipid chain order imposed by the specific environment. Our results are relevant for resolving local lipid properties of deformed, stressed, or frustrated membranes that notably emerge around integral membrane proteins or during different membrane remodeling processes.
†Biozentrum - Center for Molecular Sciences, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland.
Niklaus
N
Johner
‡Institute of Chemistry and the Fritz Haber Research Center, The Hebrew University, Jerusalem 91904, Israel.
Daniel
D
Harries
§Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, New York 10065, United States.
George
G
Khelashvili
bending rigidity; curvature; inverted hexagonal phase; lamellar phase; membrane elastic properties; tilt modulus