SpeakerProf. Lutz Maibaum, Asst. Prof of Chemistry at U of Washington (Host: Profs. Baron Peters and Joan Emma Shea)
Date and LocationWednesday October 25, 2017 11:00am to 12:00pm
Cellular membranes are mixtures of phospholipids, sterols and proteins. The spatial organization of these components is crucial for its biological function. We present computer simulation and modeling results for two specific mechanisms that can lead to such organization in an otherwise disordered fluid. First, we study the thermodynamic phase behavior of multicomponent lipid mixtures that can exhibit large-scale composition heterogeneities. The latter have attracted much attention recently as they might form the basis for lipid rafts, small domains rich in sterols that corral membrane proteins. We find a wide range of membrane systems that exhibit composition correlations over nanometer length scales. Second, we explore the effects of protein binding to the membrane, which locally suppresses thermal fluctuations. This gives rise to an entropic interaction between proteins that is transmitted by the membrane’s elastic properties. We develop a hybrid model that combines a continuum description of the membrane with a particle representation of the proteins, and show that the membrane-induced interaction is attractive and can act on length scales much larger than typical intermolecular forces.