title: Combination of MD Simulations with Two-State Kinetic Rate Modeling Elucidates the Chain Melting Transition of Phospholipid Bilayers for Different Hydration Levels.
abstract: The phase behavior of membrane lipids plays an important role in the formation of functional domains in biological membranes and crucially affects molecular transport through lipid layers, for instance, in the skin. We investigate the thermotropic chain melting transition from the ordered Lβ phase to the disordered Lα phase in membranes composed of dipalmitoylphosphatidylcholine (DPPC) by atomistic molecular dynamics simulations in which the membranes are subject to variable heating rates. We find that the transition is initiated by a localized nucleus and followed by the propagation of the phase boundary. A two-state kinetic rate model allows characterizing the transition state in terms of thermodynamic quantities such as transition state enthalpy and entropy. The extrapolated equilibrium melting temperature increases with reduced membrane hydration and thus in tendency reproduces the experimentally observed dependence on dehydrating osmotic stress.
authors.affiliation: Fachbereich Physik, Freie Universität Berlin , D-14195 Berlin, Germany.
authors.forename: Bartosz
authors.initials: B
authors.lastname: Kowalik
authors.affiliation: Institute of Physical Chemistry, Heidelberg University , D-69120 Heidelberg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schubert
authors.affiliation: Department of Physics, Ritsumeikan University , Kusatsu, 525-8577 Shiga, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Wada
authors.affiliation: Institute of Physical Chemistry, Heidelberg University , D-69120 Heidelberg, Germany.|Institute for Integrated Cell-Material Sciences (WPI iCeMS), Kyoto University , 606-8501 Kyoto, Japan.
authors.forename: Motomu
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Fachbereich Physik, Freie Universität Berlin , D-14195 Berlin, Germany.
authors.forename: Roland R
authors.initials: RR
authors.lastname: Netz
authors.affiliation: Biomaterials Department, Max Planck Institute of Colloids and Interfaces , D-14476 Potsdam, Germany.
authors.forename: Emanuel
authors.initials: E
authors.lastname: Schneck
mesh_terms: D003681:Dehydration; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D009997:Osmotic Pressure; D010743:Phospholipids / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D008051:Lipid Bilayers; D010743:Phospholipids