Electron paramagnetic resonance of contractile systems
Review articleOpen access
1982/01/01 Full-length article DOI: 10.1016/0076-6879(82)85054-4
Publisher SummaryThis chapter presents application of electron paramagnetic resonance (EPR) in contractile systems. The application of EPR to studies of the proteins of the myofibrii have centered largely on the use of nitroxide spin labels covalently bound to purified proteins and more recently to labels selectively bound to myosin heads of intact myofibrils and glycerinated muscle fibers. In addition to their use as reporter groups when bound to proteins la nitroxides have also found use in evaluating changes in environmental polarity, a flexibility and rotational motion of proteins or segments of proteins, and distances between two paramagnetic centers or a paramagnetic center and a nuclear spin. Nitroxides have been extensively employed in studies on membranes and lipid bilayers where they have been used to study fluidity, structure, and protein mobility. In addition, the use of paramagnetic metal ions has been combined with the use of spin labels, giving rise to a technique that has been referred to as the spin probe-spin label method in which the effects of a perturbing spin, usually the metal ion, on an observed spin, usually the nitroxide, are investigated.
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