title: Effect of adenosine 5'-[beta,gamma-imido]triphosphate on myosin head domain movements.
abstract: Conventional and saturation transfer electron paramagnetic resonance spectroscopy (EPR and ST EPR) was used to study the orientation of probe molecules in muscle fibers in different intermediate states of the ATP hydrolysis cycle. A separate procedure was used to obtain ST EPR spectra with precise phase settings even in the case of samples with low spectral intensity. Fibers prepared from rabbit psoas muscle were labeled with isothiocyanate spin labels at the reactive thiol sites of the catalytic domain of myosin. In comparison with rigor, a significant difference was detected in the orientation-dependence of spin labels in the ADP and adenosine 5'-[beta,gamma-imido]triphosphate (AdoPP[CH2]P) states, indicating changes in the internal dynamics and domain orientation of myosin. In the AdoPP[CH2]P state, approximately half of the myosin heads reflected the motional state of ADP-myosin, and the other half showed a different dynamic state with greater mobility.
authors: Central Research Laboratory and Institute of Biophysics, School of Medicine, University of Pécs, Hungary.
authors: Nóra
authors: N
authors: Hartvig
authors: Dénes
authors: D
authors: Lõrinczy
authors: Nelli
authors: N
authors: Farkas
authors: Joseph
authors: J
authors: Belagyi
mesh_terms: D000266:Adenylyl Imidodiphosphate / Q000737:chemistry*; D000818:Animals; D004578:Electron Spin Resonance Spectroscopy; D020409:Molecular Motor Proteins; D018485:Muscle Fibers, Skeletal / Q000737:chemistry; D009218:Myosins / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D011817:Rabbits
chemical_list: D020409:Molecular Motor Proteins; D000266:Adenylyl Imidodiphosphate; D009218:Myosins