Regensburg 2007 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 22: Molecular Machines
BP 22.10: Vortrag
Donnerstag, 29. März 2007, 12:30–12:45, H43
Stochastic thermodynamics of the single F_1-ATPase molecules — •Alexander Kovalev1, Florian Werz1, Michael Börsch1, Dirk Bald3, Tim Schmiedl2, Udo Seifert2, Jörg Wrachtrup1, and Carsten Tietz1 — 13rd Institute of Physics, Stuttgart University, Stuttgart, Germany — 2II. Institute for Theoretical Physics, Stuttgart University, Stuttgart, Germany — 3Department of Structural Biology, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
A water soluble part of the whole transmembrane protein F0F1-ATP synthase, F1-ATPase, is a rotary motor driven by ATP hydrolysis. The back rotation of F1-ATPase induces ATP synthesis. Due to the 3 fold symmetry the central subunit of F1-ATPase rotates in three steps pausing during ATP-binding. The single molecule study allows us to reconstruct the distribution of the rate constants, which seems to be higher compared to ensemble measurements. We have determined different statistical quantities characterizing dynamical properties of F1-ATPase transition rates between its three states. A fluctuation theorem relating the forward and backward steps was verified on single trajectories using the 3-state model. That gives us opportunity to describe F1-ATPase behaviour using stochastic thermodynamics theory. The time dependent conditional probabilities for F1-ATPase to be in a certain state were compared with solution of the master equations. The 3-states model trajectories were simulated to estimate the statistical errors.