The mechanism for mechanochemical energy transduction in actin-myosin interaction revealed by in vitro motility assay with ATP analogues

We investigated in vitro motility of F-actin on heavy meromyosin (HMM) and nucleotide triphosphatase activity of acto-HMM by using ATF analogues of various nucleotide triphosphates (NTPs) and enzymatically cleaved actins. The sliding velocity did not correlate with the actin activated HMM-NTPase activity, but correlated strongly with the reciprocal of NTPase activity of HMM itself, i.e., the cycle time of HMM NTPase. This indicated;hat with ATP the complex of myosin with the product, M . ADP . Pi, at the long lived intermediate state of the rate limiting step would play a key role for efficient mechanochemical energy transduction during actin-myosin interaction. (C) 1996 Academic Press, Inc.