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A branched kinetic scheme describes the mechanochemical coupling of Myosin Va processivity in response to substrate

Zhang, Chong, Ali, M. Yusuf, Warshaw, David M., Kad, Neil M. (2012) A branched kinetic scheme describes the mechanochemical coupling of Myosin Va processivity in response to substrate. Biophysical journal, 103 (4). pp. 728-737. ISSN 1542-0086. (doi:10.1016/j.bpj.2012.07.033) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided) (KAR id:42943)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided.
Official URL:
http://dx.doi.org/10.1016/j.bpj.2012.07.033

Abstract

Myosin Va is a double-headed cargo-carrying molecular motor that moves processively along cellular actin filaments. Long processive runs are achieved through mechanical coordination between the two heads of myosin Va, which keeps their ATPase cycles out of phase, preventing both heads detaching from actin simultaneously. The biochemical kinetics underlying processivity are still uncertain. Here we attempt to define the biochemical pathways populated by myosin Va by examining the velocity, processive run-length, and individual steps of a Qdot-labeled myosin Va in various substrate conditions (i.e., changes in ATP, ADP, and P(i)) under zero load in the single-molecule total internal reflection fluorescence microscopy assay. These data were used to globally constrain a branched kinetic scheme that was necessary to fit the dependences of velocity and run-length on substrate conditions. Based on this model, myosin Va can be biased along a given pathway by changes in substrate concentrations. This has uncovered states not normally sampled by the motor, and suggests that every transition involving substrate binding and release may be strain-dependent.

Item Type: Article
DOI/Identification number: 10.1016/j.bpj.2012.07.033
Subjects: Q Science
Divisions: Divisions > Division of Natural Sciences > Biosciences
Depositing User: Neil Kad
Date Deposited: 15 Sep 2014 19:18 UTC
Last Modified: 16 Nov 2021 10:17 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/42943 (The current URI for this page, for reference purposes)

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