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A hydrophilic channel is involved in oxidative inactivation of a [NiFeSe] hydrogenase

DOI: 10.1021/acscatal.9b02347 DOI Help

Authors: Sonia Zacarias (Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa) , Adriana Temporão (Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa) , Melisa Del Barrio (Aix Marseille Univ., CNRS) , Vincent Fourmond (Aix Marseille Univ., CNRS) , Christophe Leger (Aix Marseille Univ., CNRS) , Pedro Matias (Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa; iBET, Instituto de Biologia Experimental e Tecnológica) , Inês Antunes Cardoso Pereira (Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Catalysis

State: Published (Approved)
Published: August 2019
Diamond Proposal Number(s): 10515

Abstract: Hydrogenases are metalloenzymes that catalyze the redox conversion between H2 and protons. The so-called [NiFeSe] hydrogenases are highly active for both H2 production and oxidation, but like all hydrogenases, they are inhibited by O2. In the [NiFeSe] enzyme from Desulfovibrio vulgaris Hildenborough this results from the oxidation of an active site cysteine ligand. We designed mutations that constrict a hydrophilic channel that connects the protein surface to this active site cysteine. Two of the variants show markedly increased tolerance to O2 inactivation, while retaining high catalytic activities in both directions of the reaction, and structural studies confirm that these mutations prevent the oxidation of the cysteine. Our results indicate that the diffusion of O2 or ROS to the active site can occur through a hydrophilic water channel, in contrast to the widely held assumption that only hydrophobic channels are involved in active site inactivation. This provides an original strategy for optimizing the enzyme by protein engineering.

Journal Keywords: Hydrogen; hydrogenases; selenium; hydrophilic channel; sulfenate; sulfinate

Subject Areas: Chemistry


Instruments: I03-Macromolecular Crystallography

Other Facilities: ESRF