M. Marques, R. Coelho, I. Pereira
Jul 17, 2013
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Influential Citations
34
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Journal
International Journal of Hydrogen Energy
Abstract
Abstract Hydrogenases are enzymes that can potentially be used in bioelectrical devices or for biological hydrogen production, the most studied of which are the [NiFe] type. Most [NiFe] hydrogenases are inactivated by oxygen and the few known O2-tolerant enzymes are hydrogen-uptake enzymes, unsuitable for hydrogen production, due to strong product inhibition. In contrast, the [NiFeSe] hydrogenases, where a selenocysteine is bound to the nickel, are very attractive alternatives because of their high hydrogen production activity and fast reactivation after O2 exposure. Here we report five high-resolution crystallographic 3D structures of the soluble form of the [NiFeSe] hydrogenase from Desulfovibrio vulgaris Hildenborough in three different redox states (oxidized as-isolated, H2-reduced and air re-oxidized), which revealed the structural changes that take place at the active site during enzyme reduction and re-oxidation. The results provide new insights into the pathways of O2 inactivation in [NiFe], and in particular [NiFeSe], hydrogenases. In addition, they suggest that different enzymes may display different oxidized states upon exposure to O2, which are probably determined by the protein structure.