[Study of conformational transitions in myosin using 2 types of spin label]

It is shown that three types of ESR spectra of myosin labeled with both acetate and acetamide spin labels are distinguished. These three types are the spectrum of initial preparation, myosin--ADP complex spectrum and the spectrum recorded during ATP hydrolysis. The ESR spectra of myosin labeled with acetate spin label are more sensitive to conformational changes of myosin induced by complex formation and temperature.