Permeation through a lamellar stack of lipid mixtures

Abstract

We study material transport and permeation through a lamellar stack of multicomponent lipid membranes by performing Monte Carlo simulations of a stacked two-dimensional Ising model in presence of permeants. In the model, permeants are transported through the stack via in-plane lipid clusters, which are inter-connected in the vertical direction. These clusters are formed transiently by concentration fluctuations of the lipid mixture, and the permeation process is affected especially close to the critical temperature of the binary mixture. We show that the permeation rate decays exponentially as function of temperature and permeant lateral size, whereas the dependency on the characteristic waiting time obeys a stretched exponential function. The material transport through such lipid clusters can be significantly affected around physiological temperatures.

Lattice Models for Protein Organization throughout Thylakoid Membrane Stacks

“…They also greatly reduce the computational cost of sampling pertinent fluctuations, which are simply inaccessible for biomolecular systems near phase boundaries when considered in full atomistic detail. This perspective has even been applied to lipid ordering in stacks of membrane layers, but not in the context of protein ordering or photosynthesis (36)(37)(38)(39).…”

“…The computational works mentioned above utilize coarsegrained particle approaches, whereas our model will be a lattice-based approach; in this manner, we attempt to create the simplest possible explanatory model for vertical ordering in photosynthetic membranes (9,(16)(17)(18). Lattice models have been used for myriad studies of lipid organization in bilayers, as well as for lipid-protein membrane systems (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37).…”