Electron-tunneling pathways in proteins

Abstract

Electron-transfer (ET) reactions are key steps in photosynthesis, respiration, drug metabolism, and many other biochemical processes. These ET processes commonly occur between protein-bound prosthetic groups that are separated by large molecular distances (often greater than 10 Å. Although the electron donors and acceptors in these reactions are expected to be weakly coupled, the ETs are remarkably fast and proceed with high specificity. On page 1748 of this issue, Pelletier and Kraut (1) present work on the crystal structures of cytochrome c-cytochrome c peroxidase complexes that could lead to a much deeper understanding of how the intervening medium controls interprotein ET reactions.