Internal motions in myosin head: effect of ADP and ATP.
Internal flexibility of myosin heads in glycerinated muscle fibres in the presence of MgADP plus orthovanadate and after addition of Ca-ATP was studied using an isothiocyanate-based spin label attached to the reactive sulfhydryl sites of myosin. The spin labels were immobilized on the microsecond time scale and exhibited significant orientational order in rigor. In AM+.ADP.V(i) state a smaller fraction of ordered population was found showing distinct orientation from rigor; the larger population of heads was in dynamically disordered state. This new ordered population of heads was detected even in contracting fibres.
Belagyi
J
J
Central Research Laboratory, University Medical School, Pécs, Hungary.
Lörinczy
D
D
D000244:Adenosine Diphosphate / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D004578:Electron Spin Resonance Spectroscopy; D066298:In Vitro Techniques; D008301:Maleimides; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D009218:Myosins / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D011817:Rabbits; D013113:Spin Labels; D013861:Thiocyanates
D008301:Maleimides; D013113:Spin Labels; D013861:Thiocyanates; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D009218:Myosins