Brownian Dynamics Simulation of Charged Membrane Components: Implications for their Lateral Distribution and Voltage Dependence of Ion Transport through Membranes

Abstract

The modern understanding of biological membranes is based on the experimentally proved assumption that their components (proteins and lipids) behave like a two-dimensional fluid and thus are in general able to diffuse over the membrane. However, aggregation of protein molecules and inhomogeneous distribution of other membrane components are often observed (for instance, dense packings of bacteriorhodopsin in the purple membrane of halobacteria). Different physical principles have been held responsible to cause non-random distribution¹. The objective of the present paper is to assess the contribution of conceivable electric interactions of possible discrete membrane charges carried by membrane proteins or lipids to lateral membrane order. Because electric charges are thought to play an important role in membrane processes it is worth considering the impact of the lateral electric potential on the diffusion of membrane particles.