Electron Transfer in Heme Protein-CdSe/CdS Nanorod Complexes

Abstract

Electron transfer in protein-protien complexes is highly engineered and regulated by high fidelity interactions and tight control over geometry. Achieving such exquisite control over electron transfer in colloidal systems is a standing goal in the engineering of nanoscale systems for energy conversion and other applications. We show that by mutating an electron transfer protein, cytochrome c, we can enable reversible photoinduced electron transfer with colloidal CdSe/CdS nanorods. Further, we can use site directed mutagenesis of protein surface residues to control protein orientation on the nanoparticle surface, thus modulating electronic coupling and electron transfer efficiency. These results represent and important step in gaining rational control over electron transfer processes in nanoscale systems using the protein framework. Furthermore, we show that the photo-reduction process can be exploited to probe rapid ET coupled protein dynamics.