Muscle contraction cycle, Lymn-Taylor

Figure 17.3 Structural events during the Lymn-Taylor muscle contraction cycle. In the rigor state (state I), myosin is strongly bound to actin in the absence of ATP. During rigor dissociation, that is, conformational transition from the rigor state to the prerecovery state (state II), myosin binds to ATP and dissociates from actin. As a result of the recovery stroke transition, myosin attains...

The specific system that we use to explore these questions is the conventional myosin, also termed myosin 11, which plays key physiological functions in muscle contraction and cell division. It is an ideal system for in-depth theoretical and computational analysis because its structural and kinetic properties have been characterized by a large body of diverse experimental techniques." For example, at the time our research was initiated, myosin 11 was one of the few motor systems for which high-resolution x-ray structures are available for multiple functional states " since then, multiple high-resolution x-ray structures have also been obtained for myosin V and VI, two other widely studied members of the myosin superfamily that are more processive in nature compared to myosin 11. The functional cycle of myosin 11 is best described by the celebrated Lymn-Taylor schane (Figure 2.1a)," in which... 

Myosin II is a molecular motor responsible for muscle contraction and intracellular cargo transport [44]. It uses the hydrolysis of ATP to drive the Lymn-Taylor cycle, which describes the cyclic interactions between myosin and the actin filament that produce motion (Figure 17.3). Induced fit during steps I->II->-III... 

Calcium plays a vitally important part in possibly as many as three sequences of the contraction—relaxation cycle of vertebrate muscle (Taylor, Lymn and Moll, 1970). In the sarcoplasmic reticulum, calcium is stored in calsequestrin, a protein which holds, with high affinity, 43 atoms of calcium per molecule. The calcium is released in response to nervous impulses and triggers a sequence of reactions that lead to contraction of the muscle. After the contraction, the calcium is pumped back into this reticulum by the calcium/magnesium-dependent ATPase. 

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See also in sourсe #XX -- [ ]

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