In situ monitoring of the catalytic activity of cytochrome C oxidase in a biomimetic architecture

Biophys J. 2008 Aug;95(3):1500-10. doi: 10.1529/biophysj.107.122747. Epub 2008 Apr 25.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomimetic Materials / chemistry*
  • Catalysis
  • Electron Transport Complex IV / chemistry*
  • Enzyme Activation
  • Enzymes, Immobilized / chemistry
  • Paracoccus denitrificans / enzymology*

Substances

  • Enzymes, Immobilized
  • Electron Transport Complex IV