In situ monitoring of the catalytic activity of cytochrome C oxidase in a biomimetic architecture.
Cytochrome c oxidase (CcO) from Paracoccus denitrificans was immobilized in a strict orientation via a his-tag attached to subunit I on a gold film and reconstituted in situ into a protein-tethered bilayer lipid membrane. In this orientation, the cytochrome c (cyt c) binding site is directed away from the electrode pointing to the outer side of the protein-tethered bilayer lipid membrane architecture. The CcO can thus be activated by cyt c under aerobic conditions. Catalytic activity was monitored by impedance spectroscopy, as well as cyclic voltammetry. Cathodic and anodic currents of the CcO with cyt c added to the bulk solution were shown to increase under aerobic compared to anaerobic conditions. Catalytic activity was considered in terms of repeated electrochemical oxidation/reduction of the CcO/cyt c complex in the presence of oxygen. The communication of cyt c bound to the CcO with the electrode is discussed in terms of a hopping mechanism through the redox sites of the enzyme. Simulations supporting this hypothesis are included.
Friedrich
Marcel G
MG
Max Planck Institute for Polymer Research, 55128 Mainz, Germany.
Plum
Markus A
MA
Santonicola
M Gabriella
MG
Kirste
Vinzenz U
VU
Knoll
Wolfgang
W
Ludwig
Bernd
B
Naumann
Renate L C
RL
D040761:Biomimetic Materials / Q000737:chemistry*; D002384:Catalysis; D003576:Electron Transport Complex IV / Q000737:chemistry*; D004789:Enzyme Activation; D004800:Enzymes, Immobilized / Q000737:chemistry; D010231:Paracoccus denitrificans / Q000201:enzymology*
D004800:Enzymes, Immobilized; D003576:Electron Transport Complex IV