Drug effect unveils inter-head cooperativity and strain-dependent ADP release in fast skeletal actomyosin.

ABSTRACT: Amrinone is a bipyridine compound with characteristic effects on the force-velocity relationship of fast skeletal muscle, including a reduction in the maximum shortening velocity and increased maximum isometric force. Here we performed experiments to elucidate the molecular mechanisms for these effects, with the additional aim to gain insight into the molecular mechanisms underlying the force-velocity relationship. In vitro motility assays established that amrinone reduces the sliding velocity of heavy meromyosin-propelled actin filaments by 30% at different ionic strengths of the assay solution. Stopped-flow studies of myofibrils, heavy meromyosin and myosin subfragment 1, showed that the effects on sliding speed were not because of a reduced rate of ATP-induced actomyosin dissociation be

SUBMITTER: Albet-Torres N 

PROVIDER: S-EPMC2755700 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature