posted on 2006-09-13, 14:27authored byPaul B. Conibear, Clive R. Bagshaw, Piotr G. Fajer, Mihály Kovács, András Málnási-Csizmadia
It has long been known that binding of actin and nucleotides to myosin are
antagonistic, an observation that led to the biochemical basis for the crossbridge
cycle of muscle contraction. Thus ATP binding to actomyosin causes actin
dissociation, while actin binding to the myosin accelerates ADP and phosphate
release. Structural studies have indicated that communication between the actin
and nucleotide binding sites involves the opening and closing of the cleft between
the upper and lower 50K domains of the myosin he ad. Here we test the proposal
that the cleft responds to actin and nucleotide binding in a reciprocal manner and show that cleft movement is coupled to actin binding and dissociation. We
monitored cleft movement using pyrene excimer fluorescence from probes engineered across the cleft.
History
Citation
Nature Structural and Molecular Biology, 2003, 10(10), pp. 831-835