Holmes, K.C. and Geeves, M.A. (2000) The structural basis of muscle contraction. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 355 (1396). pp. 419-431. ISSN 0962-8436.
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The myosin cross-bridge exists in two conformations, which differ in the orientation of a long lever arm. Since the lever arm undergoes a 60 degrees rotation between the two conformations, which would lead to a displacement of the myosin filament of about 11 nm, the transition between these two states has been associated with the elementary 'power stroke' of muscle. Moreover, this rotation is coupled with changes in the active site (CLOSED to OPEN), which probably enable phosphate release. The transition CLOSED to OPEN appears to be brought about by actin binding. However, kinetics shows that the binding of myosin to actin is a two-step process which affects both ATP and ADP affinity and trice versa. The structural basis of these effects is only partially explained by the presently known conformers of myosin. Therefore, additional states of the myosin cross-bridge should exist. Indeed, cryoelectron microscopy has revealed other angles of the lever arm induced by ADP binding to a smooth muscle actin-myosin complex.
|Uncontrolled keywords:||muscle mechanism; actin; myosin; X-ray structure; kinetics|
|Subjects:||Q Science > QH Natural history > QH301 Biology|
|Divisions:||Faculties > Science Technology and Medical Studies > School of Biosciences|
|Depositing User:||O.O. Odanye|
|Date Deposited:||03 Apr 2009 09:39|
|Last Modified:||25 Jun 2012 13:32|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/16229 (The current URI for this page, for reference purposes)|
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