Myosin V

Chemomechanical-coupling ratchet with load-induced mechanical slip

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

A chemomechanical-network model for myosin V is presented on the basis of both the nucleotide-dependent binding affinity of the head to an actin filament (AF) and asymmetries and similarity relations among the chemical transitions due to an intramolecular strain of the leading and trailing heads. The model allows for branched chemomechanical cycles and takes into account not only two different force-generating mechanical transitions between states wherein the leading head is strongly bound and the trailing head is weakly bound to the AF but also load-induced mechanical-slip transitions between states in which both heads are strongly bound. The latter is supported by the fact that ATP-independent high-speed backward stepping has been observed for myosin V, although such motility has never been for kinesin. The network model appears as follows: (1) the high chemomechanical-coupling ratio between forward step and ATP hydrolysis is achieved even at low ATP concentrations by the dual mechanical transitions; (2) the forward stepping at high ATP concentrations is explained by the front head-gating mechanism wherein the power stroke is triggered by the inorganic-phosphate (Pi) release from the leading head; (3) the ATP-binding or hydrolyzed ADP.Pi-binding leading head produces a stable binding to the AF, especially against backward loading.

Original languageEnglish
Article number13489
JournalScientific Reports
Volume7
Issue number1
DOIs
Publication statusPublished - Dec 1 2017

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myosins
adenosine triphosphate
slip
filaments
adenosine diphosphate
locomotion
nucleotides
strokes
affinity
hydrolysis
phosphates
high speed
asymmetry
cycles

ASJC Scopus subject areas

  • General

Cite this

Myosin V : Chemomechanical-coupling ratchet with load-induced mechanical slip. / Sumi, Tomonari.

In: Scientific Reports, Vol. 7, No. 1, 13489, 01.12.2017.

Research output: Contribution to journalArticle

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