The swinging lever-arm hypothesis of muscle contraction

Remarks on Muscle Contraction Mechanism

Muscle contraction mechanism is discussed by reforming the model described in an article by Mitsui (Adv. Biophys. 1999, 36, 107-158). A simple thermodynamic relationship is presented, which indicates that there is an inconsistency in the power stroke model or the swinging lever model. To avoid this difficulty, a new model is proposed. It is assumed that a myosin head forms a polaron-like comple...

Evidence for the Essential Role of Myosin Head Lever Arm Domain and Myosin Subfragment-2 in Muscle Contraction

Insight into the actin-myosin motor from x-ray diffraction on muscle.

The origin of reflections in the x-ray diffraction pattern from striated muscle and their use for understanding the structural organization of the contractile machinery are presented and discussed. Results of x-ray diffraction experiments obtained by a number of research groups using a variety of protocols revealed structural changes in contracting muscles which are interpreted in terms of mole...

Structural mechanism of the recovery stroke in the myosin molecular motor.

The power stroke pulling myosin along actin filaments during muscle contraction is achieved by a large rotation ( approximately 60 degrees ) of the myosin lever arm after ATP hydrolysis. Upon binding the next ATP, myosin dissociates from actin, but its ATPase site is still partially open and catalytically off. Myosin must then close and activate its ATPase site while returning the lever arm for...

Instabilities in the transient response of muscle.

We investigate the isometric transient response of muscle using a quantitative stochastic model of the actomyosin cycle based on the swinging lever-arm hypothesis. We first consider a single pair of filaments, and show that when values of parameters such as the lever-arm displacement and the cross-bridge elasticity are chosen to provide effective energy transduction, the T(2) curve (the tension...