Resonance effects in strongly exothermic long‐range electron transfer and their possible implications for the behaviour of site‐directed mutant proteins

Abstract

Long‐range electron transfer investigations of hemoproteins, blue copper and iron‐sulphur proteins frequently rest on electronically excited metall centres. When the excitation energy approaches the oxidation or reduction potentials of intermediate residues the superexchange view normally used, however, fails and a variety of new dynamic features arise. These all involve population of the intermediate cation or anion residue states which can be partially or wholly vibrationally relaxed. We discuss suitable views and a new theoretical formalism for these phenomena. We also note some important implication for site‐directed mutagenesis in long‐range, strongly exothermic electron transfer processes.