How oxygen reacts with oxygen-tolerant respiratory [NiFe]-hydrogenases

Philip Wulff, Christopher C. Day, Frank Sargent, Fraser A. Armstrong (Lead / Corresponding author)

    Research output: Contribution to journalArticlepeer-review

    77 Citations (Scopus)

    Abstract

    An oxygen-tolerant respiratory [NiFe]-hydrogenase is proven to be a four-electron hydrogen/oxygen oxidoreductase, catalyzing the reaction 2 H2 + O2 = 2 H2O, equivalent to hydrogen combustion, over a sustained period without inactivating. At least 86% of the H2O produced by Escherichia coli hydrogenase-1 exposed to a mixture of 90% H2 and 10% O2 is accounted for by a direct four-electron pathway, whereas up to 14% arises from slower side reactions proceeding via superoxide and hydrogen peroxide. The direct pathway is assigned to O2 reduction at the [NiFe] active site, whereas the side reactions are an unavoidable consequence of the presence of low-potential relay centers that release electrons derived from H2 oxidation. The oxidase activity is too slow to be useful in removing O2 from the bacterial periplasm; instead, the four-electron reduction of molecular oxygen to harmless water ensures that the active site survives to catalyze sustained hydrogen oxidation.

    Original languageEnglish
    Pages (from-to)6606-6611
    Number of pages6
    JournalProceedings of the National Academy of Sciences of the United States of America
    Volume111
    Issue number18
    Early online date8 Apr 2014
    DOIs
    Publication statusPublished - 6 May 2014

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