title: In situ monitoring of the catalytic activity of cytochrome C oxidase in a biomimetic architecture.
abstract: 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.
authors.affiliation: Max Planck Institute for Polymer Research, 55128 Mainz, Germany.
authors.forename: Marcel G
authors.initials: MG
authors.lastname: Friedrich
authors.forename: Markus A
authors.initials: MA
authors.lastname: Plum
authors.forename: M Gabriella
authors.initials: MG
authors.lastname: Santonicola
authors.forename: Vinzenz U
authors.initials: VU
authors.lastname: Kirste
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Knoll
authors.forename: Bernd
authors.initials: B
authors.lastname: Ludwig
authors.forename: Renate L C
authors.initials: RL
authors.lastname: Naumann
mesh_terms: 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*
chemical_list: D004800:Enzymes, Immobilized; D003576:Electron Transport Complex IV