Implicit modeling of membranes: How much physics can we incorporate?

COMP 386

Michael Feig, feig@msu.edu, Department of Biochemistry & Molecular Biology, Michigan State University, 218 Biochemistry Bldg, East Lansing, MI 48824
Implicit models of biological membranes are attractive for simulations of membrane-bound peptides and proteins because they greatly reduce the complexity of the simulated systems. However, a key question remains to what extent implicit models without any explicit lipids can accurately represent all of the physics involved in protein-lipid interactions. A heterogeneous dielectric model describes membranes as layers of low- and high-dielectric environments. In combination with a non-polar contribution that varies as a function of membrane insertion such a model can provide a realistic account of most of the underlying physics. The extension of such a model to include van der Waals interactions, an anisotropic cost of cavity formation, and a response of the modeled bilayer thickness to the presence of a protein or peptide is presented. First tests of the model in simulations with the Generalized Born formalism are presented for peptide-membrane insertion and helix-helix association applications.