3-DIMENSIONAL STRUCTURE OF MYOSIN SUBFRAGMENT-1 - A MOLECULAR MOTOR

Directed movement is a characteristic of many living organisms and occ urs as a result of the transformation of chemical energy into mechanic al energy. Myosin is one of three families of molecular motors that ar e responsible for cellular motility. The three-dimensional structure o f the head portion of myosin, or subfragment-1, which contains both th e actin and nucleotide binding sites, is described. This structure of a molecular motor was determined by single crystal x-ray diffraction. The data provide a structural framework for understanding the molecula r basis of motility.