Redox Properties of the Membrane Proteins from the Respiratory Chain

Abstract

This review focuses on the electrochemical and spectroelectrochemical studies that gave insight into redox potentials of the four mitochondrial complexes and their homologues from bacterial respiratory chains using O2 as a terminal acceptor, thus providing crucial information about their reaction mechanism. Advantages and limitations of the use of the different techniques for the study of membrane proteins are presented. Electrocatalytic experiments are described that revealed specific features of the reaction with the substrates and inhibitors. An overview is given on the great variability of the redox and catalytic properties of the enzymes in different organisms that may be due to adaptation to the specific environments in which these enzymes function. The adaptation of the redox chain to the different types of quinone and substrates is analyzed, and future studies are discussed.

Oxalate decarboxylase uses electron hole hopping for catalysis

“…Long-range electron transfer (LRET) is recognized as an essential feature of redox catalytic proteins ( 1 , 2 , 3 , 4 ). Prominent examples include photosynthetic proteins ( 5 , 6 , 7 ) and the proteins that facilitate charge transfer in the respiratory chain ( 8 ), but there are many others ( 9 ). LRET between different redox cofactors in these proteins typically occurs by an electron tunneling mechanism, mediated by protein superexchange interactions.…”

Membrane Protein Modified Electrodes in Bioelectrocatalysis

“…Spectroelectrochemistry combines electrochemistry and spectroscopic approaches to monitor a specific molecular response while varying the electrode potential [122,123]. This can be done with proteins in solution [124] or immobilised on the electrode surface [125,126]. Insights into reaction mechanisms of membrane enzymes could be gained by methods such as UV-vis spectroelectrochemistry and infrared spectroelectrochemistry.…”

Surface Enhanced Infrared Characterization Using Disordered Slit-Antenna Arrays for the Detection of Electrodeposited Cytochrome C

“…Relating protein function with conformational changes is of great interest in biology. In the case of redox proteins, involved in many essential processes in biology, the combination of electrochemical and spectroscopical measurements can provide this valuable information [1,2]. Infrared spectroscopy is particularly interesting as it provides a nondestructive, label free, unambiguous identification of local structural protein rearrangements.…”

“…The slits were designed to amplify the signal corresponding to the absorption of the Amide I band characteristic of proteins. This soluble redox protein of the respiratory chain has been extensively studied electrochemically [11] and spectroscopically [2] and serves as a good bench mark to test the utility of these microstructured surfaces to study the infrared signal of a monolayer of an electrochemically active protein.…”