caa a22 4500 475745140 CHVBK 20180406123511.0 cr unu---uuuuu 170329e20000501xx s 000 0 eng 10.1023/A:1005615925390 doi (NATIONALLICENCE)springer-10.1023/A:1005615925390 A thermodynamic muscle model and a chemical basis for A.V. Hill's muscle equation [Elektronische Daten] [Josh Baker, David Thomas] Direct measurements of a relationship between force and actin-myosin biochemistry in muscle suggest that molecular forces in active muscle rapidly equilibrate among, not within, individual myosin crossbridges [Baker et al. (1999) Biophys J 77: 2657-2664]. This observation suggests a thermodynamic model of muscle contraction in which muscle, not an individual myosin crossbridge, is treated as a near-equilibrium system. The general approach can be applied to any ensemble of molecular motors that undergo a physicochemical step against a constant external potential. In this paper we apply the model to a simple two-state crossbridge scheme like that proposed by A.F. Huxley (1957) [Prog Biophys 7: 255-317], and we immediately obtain A.V. Hill's muscle equation. We show that this equation accurately describes steady-state muscle mechanics, biochemistry and energetics. This thermodynamic model provides a novel description of force-dependent actin-myosin kinetics in muscle and provides precise chemical expressions for myosin cooperativity, myosin duty ratios, the number of working strokes per ATP hydrolyzed, muscle efficiency, and energy transfer. Kluwer Academic Publishers, 2000 Baker Josh Department of Molecular Physiology and Biophysics, University of Vermont, 05405, Burlington, VT, USA aut Thomas David Department of Biochemistry, University of Minnesota Medical School, 55455, Minneapolis, MN, USA aut Journal of Muscle Research & Cell Motility Kluwer Academic Publishers 21/4(2000-05-01), 335-344 0142-4319 21:4<335 2000 21 10974 https://doi.org/10.1023/A:1005615925390 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1005615925390 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Baker Josh Department of Molecular Physiology and Biophysics, University of Vermont, 05405, Burlington, VT, USA aut NATIONALLICENCE 700 1- Thomas David Department of Biochemistry, University of Minnesota Medical School, 55455, Minneapolis, MN, USA aut NATIONALLICENCE 773 0- Journal of Muscle Research & Cell Motility Kluwer Academic Publishers 21/4(2000-05-01), 335-344 0142-4319 21:4<335 2000 21 10974 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer