Open AccessEffect of adenosine 5′‐[β,γ‐imido]triphosphate on myosin head domain movements
Author(s) -
Hartvig Nóra,
Lõrinczy Dénes,
Farkas Nelli,
Belagyi Joseph
Publication year - 2002
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1033.2002.02872.x
Subject(s) - electron paramagnetic resonance , myosin , chemistry , adenosine triphosphate , myosin atpase , myosin head , atp hydrolysis , biophysics , site directed spin labeling , spin label , nuclear magnetic resonance , atpase , myosin light chain kinase , biochemistry , biology , enzyme , physics
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′‐[β,γ‐imido]triphosphate (Ado PP [CH 2 ] P ) states, indicating changes in the internal dynamics and domain orientation of myosin. In the Ado PP [CH 2 ] 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.