Regensburg 2016 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 19: Posters - Membranes and Vesicles
BP 19.7: Poster
Montag, 7. März 2016, 17:30–19:30, Poster C
Combination of MD Simulations with Two-State Kinetic Rate Modeling Elucidates the Chain Melting Transition of Phospholipid Bilayers for Different Hydration Levels — •Bartosz Kowalik1, Thomas Schubert2, Hirofumi Wada3, Motomu Tanaka2,4, Roland Netz1, and Emanuel Schneck5 — 1Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany — 2Institute of Physical Chemistry, Heidelberg University, 69120 Heidelberg, Germany — 3Department of Physics, Ritsumeikan University, Kusatsu, 525-8577 Shiga, Japan — 4Institute for Intergrated Cell-Material Sciences, Kyoto University, 606-8501 Kyoto, Japan — 5Biomaterials Department, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
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. We investigate the thermotropic chain melting transition from the ordered gel phase to the disordered fluid phase in membranes composed of 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. The extrapolated equilibrium melting temperature increases with reduced membrane hydration and thus in tendency reproduces the experimentally observed dependence on dehydrating osmotic stress.