[Myosin head swivel in a muscular contraction model based on an hypothesis on the role of hydrogen bond excitation].

A theory of muscle contraction developed by the authors in their earlier papers based on the idea of hydrogen-bond attractive force increase under excitation is modified for the model of myosin head swivel. The hydrogen bonds are supposed to be located at a hinge or near actin-myosin contact. The energy of ATP decay is transferred to the hydrogen bonds whose operation results in myosin head swivel. Equation of actin-chain globules vibrations is considered together with the equation for myosin head swivel by an angle psi approximately pi/4. Solution of the set of equations gives the time dependence of a globule displacement and of the force acting on the transverse z-membrane of the muscle fibre. Here the force and displacement in one act of ATP decay are obtained to be of the correct order of magnitude, F approximately 13 kg per 1 cm2 of muscle section and delta 1-10(-6) cm.