Protein voltammetry and spectroscopy: integrating approaches

Cyclic voltammetry readily visualizes the redox properties of many proteins. Net electron exchange between the protein and an electrode produces an electrical current that simultaneously quantitates and characterizes the underlying redox event(s). However, no direct information regarding the molecular origin, or consequences, of electron transfer is available. Integrating voltammetric and spectroscopic methods is one route to a more ‘holistic’ description of protein electron transfer. Here, we illustrate this approach with spectroelectrochemical studies of Rhodovulum sulfidophilum cytochrome c 2 and Escherichia coli cytochrome bd that employ electronic absorbance, infra-red and magnetic circular dichroism spectroscopies.