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Journal Article

Structural mechanism of muscle contraction

MPS-Authors
http://pubman.mpdl.mpg.de/cone/persons/resource/persons93463

Holmes,  Kenneth C.
Emeritus Group Biophysics, Max Planck Institute for Medical Research, Max Planck Society;

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Citation

Geeves, M. A., & Holmes, K. C. (1999). Structural mechanism of muscle contraction. Annual Review of Biochemistry, 68, 687-728. doi:10.1146/annurev.biochem.68.1.687.


Cite as: http://hdl.handle.net/11858/00-001M-0000-0024-5669-C
Abstract
X-ray crystallography shows the myosin cross-bridge to exist in two conformations, the beginning and end of the power stroke. A long lever-arm undergoes a 60 degrees to 70 degrees rotation between the two states. This rotation is coupled with changes in the active site (OPEN to CLOSED) and phosphate release. Actin binding mediates the transition from CLOSED to OPEN. Kinetics shows that the binding of myosin to actin is a two-step process which affects ATP and ADP affinity. The structural basis of these effects is not explained by the presently known conformers of myosin. Therefore, other states of the myosin cross-bridge must exist. Moreover, cryoelectronmicroscopy has revealed other angles of the cross-bridge lever arm induced by ADP binding. These structural states are presently being characterized by site-directed mutagenesis coupled with kinetic analysis