On the molecular basis for chemomechanical energy transduction in muscle.

Abstract

Energy transduction in [vertebrate] muscle is an activity of myosin S-1 and its ligands, actin (A) and nucleotide (N). S-1 shares with other molecular particles (e.g., Hb) the property that binding events at 1 of its sites, the N site, influences binding events at a remote site, the A site (specifically, influences both the actin affinity and actin attachment angle at the A site). However, there is a crucial difference between S-1 and the better-known systems. Because the N site is enzymatic, it has a temporal sequence of occupants; this imposes a temporal sequence of actin attitudes, i.e., a sequence of mechanical events.