Studying the interacting head motif in fast, slow, and cardiac myofibrils in stopped-flow

Abstract

The kinetics of the interacting head motif (IHM) were first identified in skinned muscle fibers using fluorescence microscopy by observing fluorescent ATP being displaced by unlabelled ‘dark’ ATP. This resulted in two phases of displacement with the slower phase associated with the IHM. Since then the use of fluorimeters and various fragments of myosin have been used to probe the IHM. Myofibrils are a great system for studying this motif, as all of the muscle sarcomere components are present, including those associated with modulating the IHM.