An Investigation of the Influence of Tyrosine Local Interactions on Electron Hopping in a Model Protein.

Multi-step electron transfer reactions are important to the function of many cellular systems. The ways in which such systems have evolved to direct electrons along specific pathways are largely understood, but less so are the ways in which the reduction-oxidation potentials of individual redox sites are controlled. We prepared a series of three new artificial variants of azurin where a tyrosine (Tyr109) is situated between the native Cu ion and a Ru(II) photosensitizer tethered to a histidine (His107).