Catalytic turnover of [FeFe]-hydrogenase based on single-molecule imaging

Christopher Madden, Michael D. Vaughn, Ismael Díez-Pérez, Katherine A. Brown, Paul W. King, John Devens Gust, Ana L Moore, Thomas A Moore

Research output: Contribution to journalArticle

106 Citations (Scopus)

Abstract

Hydrogenases catalyze the interconversion of protons and hydrogen according to the reversible reaction: 2H + + 2e - H 2 while using only the earth-abundant metals nickel and/or iron for catalysis. Due to their high activity for proton reduction and the technological significance of the H +/H 2 half reaction, it is important to characterize the catalytic activity of [FeFe]-hydrogenases using both biochemical and electrochemical techniques. Following a detailed electrochemical and photoelectrochemical study of an [FeFe]-hydrogenase from Clostridium acetobutylicum (CaHydA), we now report electrochemical and single-molecule imaging studies carried out on a catalytically active hydrogenase preparation. The enzyme CaHydA, a homologue (70% identity) of the [FeFe]-hydrogenase from Clostridium pasteurianum, CpI, was adsorbed to a negatively charged, self-assembled monolayer (SAM) for investigation by electrochemical scanning tunneling microscopy (EC-STM) techniques and macroscopic electrochemical measurements. The EC-STM imaging revealed uniform surface coverage with sufficient stability to undergo repeated scanning with a STM tip as well as other electrochemical investigations. Cyclic voltammetry yielded a characteristic cathodic hydrogen production signal when the potential was scanned sufficiently negative. The direct observation of the single enzyme distribution on the Au-SAM surface coupled with macroscopic electrochemical measurements obtained from the same electrode allowed the evaluation of a turnover frequency (TOF) as a function of potential for single [FeFe]-hydrogenase molecules.

Original languageEnglish
Pages (from-to)1577-1582
Number of pages6
JournalJournal of the American Chemical Society
Volume134
Issue number3
DOIs
Publication statusPublished - Jan 25 2012

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Hydrogenase
Clostridium
Scanning tunneling microscopy
Self assembled monolayers
Protons
Enzymes
Imaging techniques
Hydrogen
Molecules
Electrochemical Scanning Microscopy
Hydrogen production
Scanning Tunnelling Microscopy
Electrochemical Techniques
Catalysis
Cyclic voltammetry
Catalyst activity
Thermodynamic properties
Earth (planet)
Nickel
Iron

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Catalytic turnover of [FeFe]-hydrogenase based on single-molecule imaging. / Madden, Christopher; Vaughn, Michael D.; Díez-Pérez, Ismael; Brown, Katherine A.; King, Paul W.; Gust, John Devens; Moore, Ana L; Moore, Thomas A.

In: Journal of the American Chemical Society, Vol. 134, No. 3, 25.01.2012, p. 1577-1582.

Research output: Contribution to journalArticle

Madden, Christopher ; Vaughn, Michael D. ; Díez-Pérez, Ismael ; Brown, Katherine A. ; King, Paul W. ; Gust, John Devens ; Moore, Ana L ; Moore, Thomas A. / Catalytic turnover of [FeFe]-hydrogenase based on single-molecule imaging. In: Journal of the American Chemical Society. 2012 ; Vol. 134, No. 3. pp. 1577-1582.
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