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BP: Fachverband Biologische Physik
BP 21: Membranes and Vesicles II
BP 21.2: Talk
Tuesday, April 1, 2014, 14:15–14:30, ZEU 250
The complexity of membrane domain formation. — •Djurre H de Jong1, Siewert J Marrink2, and Andreas Heuer1 — 1Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Germany — 2Molecular Dynamics Group, University of Groningen, The Netherlands
Living cells are enveloped by the plasma membrane (PM): a thin layer consisting of a complex mixture of lipids and proteins. Rather than being a "shopping bag" keeping together the cell content, the PM plays an active and diverse role in the functioning of the cell. A fascinating aspect of the PM is the formation of transient, lateral domains, consisting of both lipids and proteins.
The time and length scales at which these membrane domains occur make them difficult to study, both experimentally (too small, too transient) or with simulations of full atomistic detail (too large, too long timescales). Here we use coarse grain molecular dynamics (CGMD) simulations, applying the Martini force field, to gain insight in the dynamics involved. Previously we have used this model to study the partitioning of membrane proteins between different domains in model bilayers and the influence of specific proteins and minor lipid species on the formation of domains. Here we quantify the energetic contributions to phase separation that different variation in system composition have. To this aim we combined the long timescales achieved with the Martini force field with the ability to sample non-physical states using sophisticated free energy sampling methods implemented in the software packages PLUMED and Gromacs.