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Published on: November 10, 2009
The swinging lever-arm hypothesis of muscle contraction
1Max Planck Institute für medizinische Forschung, 69120 Heidelberg, Germany.
Abstract:
The molecular mechanism of muscle contraction is a problem that has exercised biophysicists and biochemists for many years. The common view of the mechanism is embodied in the 'cross-bridge hypothesis', in which the relative sliding of thick (myosin) and thin (actin) filaments in cross-striated muscle is brought about by the 'cross-bridges', parts of the myosin molecules which protrude from the thick filaments and interact cyclically with the actin filaments, transporting them by a rowing action that is powered by the hydrolysis of ATP. This hypothesis is, however, rather vague on the molecular details of cross-bridge movement and, in the light of the recently determined crystal structures of myosin and actin, it has evolved into the more precise 'swinging lever-arm hypothesis'.
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