Control of cytochrome c redox reactivity through off-pathway modifications in the protein hydrogen-bonding network.

Measurements of photoinduced Fe(2+)-to-Ru(3+) electron transfer (ET), supported by theoretical analysis, demonstrate that mutations off the dominant ET pathways can strongly influence the redox reactivity of cytochrome c. The effects arise from the change in the protein dynamics mediated by the intraprotein hydrogen-bonding network.