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40-kDa Actin-Binding Protein of Thin Filaments of the Mussel Crenomytilus grayanus Inhibits the Strong Bond Formation between Actin and Myosin Head during the ATPase Cycle

V. V. Sirenko1, A. H. Simonyan1, A. V. Dobrzhanskaya2, N. S. Shelud’ko2, and Y. S. Borovikov1*

1Institute of Cytology, Russian Academy of Sciences, Tikhoretsky pr. 4, 194064 St. Petersburg, Russia; fax: (812) 247-0341; E-mail: boroviko@mail.cytspb.rssi.ru

2Zhirmunsky Institute of Marine Biology, Far Eastern Branch of the Russian Academy of Sciences, ul. Palchevskogo 17, 690059 Vladivostok, Russia; fax: (423) 231-0900; E-mail: sheludko@stl.ru

* To whom correspondence should be addressed.

Received February 7, 2012; Revision received March 19, 2012
Mobility and spatial orientation of a novel 40-kDa actin-binding protein from the smooth muscle of the mussel Crenomytilus grayanus was studied by polarized fluorometry. The influence of this protein on orientation and mobility of the myosin heads was investigated during modeling the different stages of the ATPase cycle. The 40-kDa actin-binding protein affected the strong actin–myosin binding. We suggest that the 40-kDa actin-binding protein is involved in regulation of the actin–myosin interaction in the smooth muscle of the mussel.
KEY WORDS: actin-binding protein of the mussel Crenomytilus grayanus, ghost fibers, ATP analog, actomyosin intermediate states, conformational change of myosin subfragment-1, fluorescence polarization

DOI: 10.1134/S0006297912080093