Reversible movement of switch 1 loop of myosin determines actin interaction

Kintses, B. and Gyimesi, M. and Pearson, D.S. and Geeves, M.A. and Zeng, W. and Bagshaw, C.R. and Malnasi-Csizmadia, A. (2007) Reversible movement of switch 1 loop of myosin determines actin interaction. EMBO Journal, 26 (1). pp. 265-274. ISSN 0261-4189 .

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http://www.nature.com/emboj/journal/v26/n1/pdf/760...

Abstract

The conserved switch 1 loop of P-loop NTPases is implicated as a central element that transmits information between the nucleotide-binding pocket and the binding site of the partner proteins. Recent structural studies have identified two states of switch 1 in G-proteins and myosin, but their role in the transduction mechanism has yet to be clarified. Single tryptophan residues were introduced into the switch 1 region of myosin II motor domain and studied by rapid reaction methods. We found that in the presence of MgADP, two states of switch 1 exist in dynamic equilibrium. Actin binding shifts the equilibrium towards one of the MgADP states, whereas ATP strongly favors the other. In the light of electron cryo-microscopic and X-ray crystallographic results, these findings lead to a specific structural model in which the equilibrium constant between the two states of switch 1 is coupled to the strength of the actin-myosin interaction. This has implications for the enzymatic mechanism of G-proteins and possibly P-loop NTPases in general

Item Type: Article
Uncontrolled keywords: actomyosin interaction; G-proteins; Mg-binding; nucleotide binding; tryptophan fluorescence
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences
Depositing User: Maureen Cook
Date Deposited: 25 Apr 2008 09:51
Last Modified: 14 Jan 2010 14:09
Resource URI: http://kar.kent.ac.uk/id/eprint/2838 (The current URI for this page, for reference purposes)
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