Electron tunneling in biological molecules*
نویسندگان
چکیده
Electron transfers in photosynthesis and respiration commonly occur between protein-bound prosthetic groups that are separated by large molecular distances (often greater than 10 AÊ ). Although the electron donors and acceptors are expected to be weakly coupled, the reactions are remarkably fast and proceed with high speci®city. Tunneling timetables based on analyses of Fe/Cu to Ru electron-transfer rates for Ru-modi®ed heme and copper proteins reveal that the structure of the intervening polypeptide can control these distant donor±acceptor couplings. Multistep tunneling can account for the relatively rapid Cu to Re electron transfer observed in Re-modi®ed azurin.
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