A Biosynthetic Approach Toward Biomimetic Studies of Metalloproteins Involved in Long-range Electron Transfer

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

This research by Professor Yi Lu of the University of Illinois at Urbana-Champaign is supported by the Inorganic, Bioinorganic and Organometallic Chemistry program. The goal of this work is to elucidate the role of each ligand of an artificially introduced dicopper, Cu-A, center in azurin, which, in nature, contains a mononuclear copper site. This will enable determining ligand effects on geometric parameters, electronic structure and behavior of the Cu-A center, which are essential to the function of important charge-transfer proteins, such as cyctochrome oxidase. In addition, this study provides for the direct comparison of the structural and functional properties of three important electron transfer centers: blue (type 1) copper, Cu-A and Fe2S2. The di-iron center will be inserted into the azurin by a new technique, expressed protein ligation (EPL), which shows promise as a very efficient and cost-effective way to generate milligram quantities of proteins containing unnatural amino acids. Electron-transfer proteins are vital to fundamental life processes. The effects of the various amino acids surrounding the unusual Cu-A site artificially placed in this protein will be systematically determined and compared with that of the normal blue copper site and another two-metal site, Fe2S2, which also occurs in essential electron-transfer proteins.