Imaging and nano-manipulation of single actomyosin motors at work

1. Muscle contraction is achieved by the sliding movement of myosin and actin using the energy of ATPase. 2. Our research has focused on the question of how chemical energy is used to perform mechanical work. Recent developments of single molecule imaging and manipulation techniques have allowed us to study the chemical and mechanical events at a molecular level. 3. There are many lines of evidence that show that the energy liberated from ATPase is stored in the actomyosin molecules for later use. 4. The displacement produced by a single ATP molecule is made up of several steps, each of 5.3 nm. Sometimes the mechanical event is delayed after the ADP is released from myosin. 5. This storage of energy may be explained by a slow conformational transition between the metastable states of the proteins. This suggestion has been supported by results obtained using single-molecule fluorescence spectroscopy.