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The myosin start‐of‐power stroke state and how actin binding drives the power stroke
Author(s) -
Preller Matthias,
Holmes Kenneth C.
Publication year - 2013
Publication title -
cytoskeleton
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 86
eISSN - 1949-3592
pISSN - 1949-3584
DOI - 10.1002/cm.21125
Subject(s) - myosin , stroke (engine) , biology , actin , power (physics) , microbiology and biotechnology , biophysics , anatomy , neuroscience , physics , quantum mechanics , thermodynamics
We propose that on binding to actin at the start of the power stroke the myosin cross‐bridge takes on the rigor configuration at the actin interface. Starting from the prepower stroke state, this can be achieved by a small movement (16° rotation) of the lower 50K domain without twisting the central β‐sheet or opening switch‐1 or switch‐2. The movement of the lower 50K domain puts a strain on the W‐helix. This strain tries to twist the β‐sheet, which could drive the power stroke. This would provide a coupling between actin binding and the execution of the power stroke. During the power stroke the β‐sheet twists, moving the P‐loop away from switch‐2, which opens the nucleotide binding pocket and separates ADP from P i . The power stroke is different from the recovery stroke because the upper and lower 50K domains are tethered in the rigor configuration. © 2013 Wiley Periodicals, Inc.