Use of sinusoidal length oscillations to detect myosin conformation by time-resolved X-ray diffraction.

Abstract

In contrast to many other theories of muscle contraction, the proposal of H.E. Huxley (Huxley, 1969), that force generation by actomyosin systems results from an active tilting of the S1 moiety of myosin, defined a structural change as the central event of the force generation process. As a result, a large range of techniques for probing structural changes in myosin have been applied to the study of contraction, but have yielded only equivocal support for the tilting S1 theory (Yanagida, 1981; Cooke et al., 1982; Tanner et al., 1992). Uniquely, because of the highly ordered structure of striated muscles, X-ray diffraction provides a powerful probe of structural events in this tissue, and the enormous advances over the last 40 years in both detector technology and intensity of X-ray sources available have permitted time-resolved X-ray diffraction studies of intact, working muscle cells to advance from the time domain of hours to that of microseconds.