Intra- and inter-molecular electron transfer in cytochrome c and myoglobinobserved by the muon spin relaxation method

Rapid electron motion in the proteins, cytochrome c and myoglobin has been studied using muon spin relaxation. Measurements between 5 and 300 K show t hat the inter-site diffusion rate for the topologically 1D motion along the polypeptide chain is only weakly dependent on temperature, Evidence for an increase in higher dimensional motion is seen around 200 K in cytochrome c , apparently reflecting structural change. For myoglobin the variation with temperature is different, reflecting the different protein dynamics of thi s molecule. (C) 2000 Elsevier Science B.V. All rights reserved.