Photoinduced electron transfer in ruthenium-modified cytochrome c
Distant heme-Ru electronic couplings have been extracted from intramolecular electron-transfer rates in Ru(histidine-X) (X=33,39,62) derivatives of cytochrome c. The rates (and the couplings) correlate with the lengths of u-tunneling pathways comprised of covalent bonds, hydrogen bonds, and through-space jumps from the histidines to the heme group.