Berlin 2008 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 25: Protein Structure and Folding

BP 25.6: Vortrag

Donnerstag, 28. Februar 2008, 15:45–16:00, PC 203

Molecular machines involving electron tunneling — •Igor Goychuk — Institut für Physik, Universität Augsburg, Germany

ATP-driven molecular machinery of living cells involves various molecular motors operating far from the thermodynamic equilibrium. They are generally believed to be essentially classical nanoengines. Nitrogenase molecular machines present, however, a clear counter-example because of the long-range electron tunneling involved in the overall reaction of nitrogen fixation (ammonia production) which these enzymes perform: the energy derived from ATP hydrolysis is used to pump electrons into the nitrogenase reaction center. The theory of quantum dissipative dynamics driven by non-equilibrium fluctuations [1] presents a general theoretical framework for such and similar electron tunneling pumps. I will discuss a tentative mechanism [2,3] based on the stochastically driven spin-boson model [4] and general principles of the free energy transduction in biology [5].
[1] I. Goychuk, P. Hänggi, Adv. Phys. 54, 525 (2005), and references therein.
[2] I. V. Kurnikov, A. K. Charnley, D. N. Beratan, J. Phys. Chem. B, 105, 5359 (2001).
[3] I. Goychuk, Molecular Simulation 9, 717 (2006).
[4] I.A. Goychuk, E.G. Petrov, V. May. J. Chem. Phys. 103, 4937 (1995); ibid. 106, 4522 (1997); Phys. Rev. E 52, 2392 (1995), ibid. 56, 1421 (1997).
[5]T.L. Hill, Free Energy Transduction in Biology (Academic Press, New York, 1977).