The relay-converter interface influences hydrolysis of ATP by skeletal muscle myosin II

Bloemink, M. J., Melkani, G. C., Bernstein, S. I. and Geeves, M. A. (2015) The relay-converter interface influences hydrolysis of ATP by skeletal muscle myosin II. The Journal of Biological Chemistry. ISSN 0021-9258.

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The interface between relay and converter domain of muscle myosin is critical for optimal myosin performance. Using Drosophila melanogaster indirect flight muscle S1 we performed a kinetic analysis of the effect of mutations in the converter and relay domain. Introduction of a mutation (R759E) in the converter domain inhibits the steady-state ATPase of myosin S1, whereas an additional mutation in the relay domain (N509K) is able to restore the ATPase towards wild-type values. The S1-R759E construct showed little effect on most steps of the actomyosin ATPase cycle. The exception was a 25-30% reduction in the rate constant of the hydrolysis step, the step coupled to the cross-bridge recovery stroke and involving a change in conformation at the relay/converter domain interface. Significantly the double mutant restored the hydrolysis step to values similar to the wild-type myosin. Modelling the relay/converter interface suggests a possible interaction between converter residue 759 and relay residue 509 in the actin-detached conformation, which is lost in R759E but is restored in N509K/R759E. This detailed kinetic analysis of Drosophila myosin carrying the R759E mutation shows that the interface between the relay loop and converter domain is important for fine tuning myosin kinetics, in particular ATP binding and hydrolysis.

Item Type: Article
Uncontrolled Keywords: Actin; fluorescence; homology modeling; kinetics; muscle; myosin; protein structure-function; sequence alignment
Subjects: Q Science > QD Chemistry > QD0241 Organic chemistry
Q Science > QH Natural history > QH0301 Biology (General)
Divisions: Faculty of Social and Applied Sciences > School of Human and Life Sciences
Depositing User: Marieke Bloemink
Date Deposited: 13 Jan 2016 16:57
Last Modified: 02 Feb 2016 10:29

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Last edited: 29/06/2016 12:23:00