[SCAN] Selenium does it better, or the fundamental role of Selenocysteine in [NiFeSe] hydrogenase maturation and catalysis| Pedro Matias

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Title: Selenium does it better, or the fundamental role of Selenocysteine in [NiFeSe] hydrogenase maturation and catalysis

Marta C. Marques, Cristina Tapia, Oscar Gutiérrez-Sanz, Ana Raquel Ramos, Kimberly L. Keller, Judy D. Wall, Antonio L. De Lacey, Inês A. C. Pereira and Pedro M. Matias

Speaker: Pedro Matias

Affiliation: Pedro Matias Lab - Industry and Medicine Applied Crystallography

Abstract: Hydrogenases are highly active enzymes for hydrogen production and oxidation. [NiFeSe] hydrogenases, where selenocysteine is a ligand to the active site Ni, have high catalytic activities and a bias for H2 production. In contrast to [NiFe] hydrogenases, they display reduced H2 inhibition and are rapidly reactivated after contact with oxygen. A homologous expression system for production of recombinant [NiFeSe] hydrogenase from Desulfovibrio vulgaris Hildenborough was used to generate a Sec489Cys variant, converting for the first time a [NiFeSe] hydrogenase to a [NiFe] type. This modification led to a severely reduced Ni incorporation, revealing the direct involvement of the selenocysteine residue in the maturation process. The Ni-depleted protein could be partly reconstituted to generate an enzyme displaying catalytic, spectroscopic and structural features characteristic of [NiFe] hydrogenases. The Ni-U489C variant highlights the crucial role played by selenium in the protection against oxidative damage and the high catalytic activities of [NiFeSe] hydrogenases.