Oxygen-Tolerant [NiFe]-Hydrogenases: The Individual and Collective Importance of Supernumerary Cysteines at the Proximal Fe-S Cluster

Michael J. Lukey, Maxie M. Roessler, Alison Parkin, Rhiannon M. Evans, Rosalind A. Davies, Oliver Lenz, Baerbel Friedrich, Frank Sargent, Fraser A. Armstrong

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    97 Citations (Scopus)

    Abstract

    An important clue to the mechanism for O-2 tolerance of certain [NiFe]-hydrogenases is the conserved presence of a modified environment around the iron sulfur cluster that is proximal to the active site. The O-2-tolerant enzymes contain two cysteines, located at opposite ends of this cluster, which are glycines in their O-2-sensitive counterparts. The strong correlation highlights special importance for electron-transfer activity in the protection mechanism used to combat O-2. Site-directed mutagenesis has been carried out on Escherichia coli hydrogenase-1 to substitute these cysteines (C19 and C120) individually and collectively for glycines, and the effects of each replacement have been determined using protein film electrochemistry and electron paramagnetic resonance (EPR) spectroscopy. The "split" iron sulfur cluster EPR signal thus far observed when oxygen-tolerant [NiFe]-hydrogenases are subjected to oxidizing potentials is found not to provide any simple, reliable correlation with oxygen tolerance. Oxygen tolerance is largely conferred by a single cysteine (C19), replacement of which by glycine removes the ability to function even in 1% O-2.

    Original languageEnglish
    Pages (from-to)16881-16892
    Number of pages12
    JournalJournal of the American Chemical Society
    Volume133
    Issue number42
    DOIs
    Publication statusPublished - 26 Oct 2011

    Keywords

    • MEMBRANE-BOUND HYDROGENASE
    • BACTERIUM AQUIFEX-AEOLICUS
    • NIFE HYDROGENASE
    • ALLOCHROMATIUM-VINOSUM
    • RALSTONIA-EUTROPHA
    • ESCHERICHIA-COLI
    • CARBON-MONOXIDE
    • INACTIVE STATES
    • ACTIVATION
    • OXIDATION

    Cite this

    Lukey, M. J., Roessler, M. M., Parkin, A., Evans, R. M., Davies, R. A., Lenz, O., Friedrich, B., Sargent, F., & Armstrong, F. A. (2011). Oxygen-Tolerant [NiFe]-Hydrogenases: The Individual and Collective Importance of Supernumerary Cysteines at the Proximal Fe-S Cluster. Journal of the American Chemical Society, 133(42), 16881-16892. https://doi.org/10.1021/ja205393w