ABSTRACT
The application of the semiclassical electron transfer (ET) theory to metalloprotein redox reactions has been appreciated for 50 years.1,2 The rst qualitative suggestion that electrons could “tunnel” between redox centers was described for photosynthetic reaction centers (PRCs) in 1966.3 The proposal that “it is unnecessary to postulate any more complicated mechanism than tunneling for moving electrons over a few tens of angstroms” in biomolecules was surprisingly perceptive,4 considering that structures were not available from which to characterize the nature and arrangement of redox partners.
