Detailed Tuning of Structure and Intramolecular Communication Are Dispensable for Processive Motion of Myosin VI

Department of Biochemistry, Stanford University, California, USA.
Biophysical Journal (Impact Factor: 3.97). 01/2011; 100(2):430-9. DOI: 10.1016/j.bpj.2010.11.045
Source: PubMed


Dimeric myosin VI moves processively hand-over-hand along actin filaments. We have characterized the mechanism of this processive motion by measuring the impact of structural and chemical perturbations on single-molecule processivity. Processivity is maintained despite major alterations in lever arm structure, including replacement of light chain binding regions and elimination of the medial tail. We present kinetic models that can explain the ATP concentration-dependent processivities of myosin VI constructs containing either native or artificial lever arms. We conclude that detailed tuning of structure and intramolecular communication are dispensable for processive motion, and further show theoretically that one proposed type of nucleotide gating can be detrimental rather than beneficial for myosin processivity.

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    • "Unlike other myosins, MVI moves towards the minus (pointed) end of actin filaments (Wells et al. 1999). Inverse directionality of MVI movement, resulting from a difference in the structure of the converter and neck regions, implies its involvement in distinct cellular functions in comparison with other myosins (Elting et al. 2011; Sweeney and Houdusse 2010). "
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