title: Poisson property of the occurrence of flip-flops in a model membrane.
abstract: How do lipid molecules in membranes perform a flip-flop? The flip-flops of lipid molecules play a crucial role in the formation and flexibility of membranes. However, little has been determined about the behavior of flip-flops, either experimentally, or in molecular dynamics simulations. Here, we provide numerical results of the flip-flops of model lipid molecules in a model membrane and investigate the statistical properties, using millisecond-order coarse-grained molecular simulations (dissipative particle dynamics). We find that there are three different ways of flip-flops, which can be clearly characterized by their paths on the free energy surface. Furthermore, we found that the probability of the number of the flip-flops is well fitted by the Poisson distribution, and the probability density function for the inter-occurrence times of flip-flops coincides with that of the forward recurrence times. These results indicate that the occurrence of flip-flops is a Poisson process, which will play an important role in the flexibilities of membranes.
authors: Department of Mechanical Engineering and Intelligent Systems, University of Electro-Communications, Tokyo 182-8585, Japan.
authors: Noriyoshi
authors: N
authors: Arai
authors: Department of Mechanical Engineering, Keio University, Yokohama 223-8522, Japan.
authors: Takuma
authors: T
authors: Akimoto
authors: Department of Mechanical Engineering, Keio University, Yokohama 223-8522, Japan.
authors: Eiji
authors: E
authors: Yamamoto
authors: Department of Pharmacology, School of Medicine, Keio University, Shinjuku-ku, Tokyo 160-8582, Japan.
authors: Masato
authors: M
authors: Yasui
authors: Department of Mechanical Engineering, Keio University, Yokohama 223-8522, Japan.
authors: Kenji
authors: K
authors: Yasuoka
mesh_terms: D002462:Cell Membrane / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D015233:Models, Statistical; D056004:Molecular Dynamics Simulation; D013816:Thermodynamics
chemical_list: D008051:Lipid Bilayers