Oriented immobilization and electron transfer to the cytochrome c oxidase

Christoph Nowak, Denise Schach, Jens Gebert, Marc Grosserueschkamp, Robert B. Gennis, Shelagh Ferguson-Miller, Wolfgang Knoll, Dieter Walz, Renate L.C. Naumann

Research output: Contribution to journalArticlepeer-review

Abstract

Direct electron transfer to cytochrome c oxidase (CcO) is investigated as a function of packing density of the surface layer. This is varied by the surface concentration of chelator molecules when the enzyme is immobilized on the electrode using the his-tag technology. Chelator molecules with a terminal nitrilotriacetic acid group are synthesized ex situ in contrast to in situ synthesis used in a previous work. Self-assembled monolayers of the chelator mixed at different mole fractions with a dilution molecule are prepared to bind the CcO after complex formation with Ni2+ ions. The CcO, which is immobilized in the solubilized form, is then reconstituted into a protein-tethered bilayer lipid membrane (ptBLM). Varying the mixing ratio of chelator to dilution molecules enabled us to control the packing density of CcO residing in the ptBLM. Subtle differences in the architecture of the protein/lipid layers revealed by surface-enhanced IR absorption spectroscopy are considered to be essential for an effective electron transfer. Cyclic voltammograms are measured under anaerobic conditions at different scan rates and analyzed by means of a model which describes the transfer of four electrons to CcO in the ptBLM. The rate constants thus obtained show a marked dependence on the packing density.

Original languageEnglish (US)
Pages (from-to)105-114
Number of pages10
JournalJournal of Solid State Electrochemistry
Volume15
Issue number1
DOIs
StatePublished - Jan 2011

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Materials Chemistry
  • Electrical and Electronic Engineering
  • General Materials Science
  • Electrochemistry

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