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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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Prof. James Kindt, Emory University
Atomistic simulation of mixed-lipid bilayers: Mixed methods for mixed membranes
AACP Seminar Series
Biomembranes typically contain a diverse array of lipids with variations in both polar headgroup and hydrophobic tail compositions. This diversity raises the question of how lipids of different type are laterally distributed within these membranes: how strongly might the local lipid composition in the membrane vary according to microenvironmental factors? Computer simulation is useful, in conjunction with experiments, to address this fundamental question within simple binary and ternary lipid bilayer model membranes. As the timescale for lipid mixing and demixing remains longer than practical trajectory times for conventional molecular dynamics simulations, adding Monte Carlo steps to a dynamics simulation provides is useful to allow an equilibrium lateral distribution of lipids to be achieved, and has facilitated the study of several mixtures in different microenvironments. In simulations where the difference between lipid structure was solely one of tail length, local environment influenced local composition strongly at edge defects, weakly in the neighborhood of a transmembrane helical peptide, and to no measurable extent in a curved bilayer. Mixed Monte Carlo/molecular dynamics simulations have furthermore shed light on the phenomenon of lipid sorting according to tail saturation between high- and low-cholesterol domains in a ternary system that is a model for the âraftâ structures widely believed to be present in cell membranes.
For more information contact Prof. Angelo Bongiorno (404-385-5169).
