Electron-transfer functionality of synthetic coiled-coil metalloproteins

Abstract

The emerging field of metalloprotein design seeks to prepare artificial proteins whose properties can mimic, enhance, and perhaps improve upon many features found in natural metalloenzymes. This review summarizes our recent efforts to prepare synthetic metalloproteins built from α-helical coiled-coils and to incorporate electron-transfer functionality within these systems. We have recently designed a cysteine-containing random-coil peptide which forms a α-helical coiled-coil upon binding various metals. The Cu1 adduct can serve as photoinduced electron-transfer agent to exogenous acceptors and undergoes collisional electron-transfer in the inverted Marcus region to various ruthenium ammine acceptors. It is speculated that this unexpected result might be due to the positioning of the Cu1 cofactor within the hydrophobic core of the protein which prohibits close approach between the donor and acceptor to slow the high driving force reaction rates below the diffusion limit. © 2006 Sociedade Brasileira de Química.