title: Molecular dynamics study of bipolar tetraether lipid membranes.
abstract: Membranes composed of bipolar tetraether lipids have been studied by a series of 25-ns molecular dynamics simulations to understand the microscopic structure and dynamics as well as membrane area elasticity. By comparing macrocyclic and acyclic tetraether and diether archaeal lipids, the effect of tail linkage of the two phytanyl-chained lipids on the membrane properties is elucidated. Tetraether lipids show smaller molecular area and lateral mobility. For the latter, calculated diffusion coefficients are indeed one order-of-magnitude smaller than that of the diether lipid. These two tetraether membranes are alike in many physical properties except for membrane area elasticity. The macrocyclic tetraether membrane shows a higher elastic area expansion modulus than its acyclic counterpart by a factor of three. Free energy profiles of a water molecule crossing the membranes show no major difference in barrier height; however, a significant difference is observed near the membrane center due to the lack of the slip-plane in tetraether membranes.
authors.affiliation: Research Institute for Computational Sciences, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8568, Japan. w.shinoda@aist.go.jp
authors.forename: Wataru
authors.initials: W
authors.lastname: Shinoda
authors.forename: Keiko
authors.initials: K
authors.lastname: Shinoda
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Baba
authors.forename: Masuhiro
authors.initials: M
authors.lastname: Mikami
mesh_terms: D001105:Archaea / Q000378:metabolism; D001703:Biophysics / Q000379:methods*; D002244:Carbon / Q000737:chemistry; D002462:Cell Membrane / Q000378:metabolism; D003198:Computer Simulation; D004058:Diffusion; D004548:Elasticity; D004583:Electrons; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry; D008560:Membrane Fluidity; D008563:Membrane Lipids / Q000737:chemistry; D008566:Membranes / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical; D008968:Molecular Conformation; D012984:Software; D013816:Thermodynamics; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D008051:Lipid Bilayers; D008055:Lipids; D008563:Membrane Lipids; D014867:Water; D002244:Carbon