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A safety cap protects hydrogenase from oxygen attack

: Winkler, Martin; Duan, Jifu; Rutz, Andreas; Felbek, Christina; Scholtysek, Lisa; Lampret, Oliver; Jaenecke, Jan; Apfel, Ulf-Peter; Gilardi, Gianfranco; Valetti, Francesca; Fourmond, Vincent; Hofmann, Eckhard; Leger, Christophe; Happe, Thomas

Volltext ()

Nature Communications 12 (2021), Art. 756, 10 S.
ISSN: 2041-1723
Zeitschriftenaufsatz, Elektronische Publikation
Fraunhofer UMSICHT Oberhausen ()

[FeFe]-hydrogenases are efficient H2-catalysts, yet upon contact with dioxygen their catalytic cofactor (H-cluster) is irreversibly inactivated. Here, we combine X-ray crystallography, rational protein design, direct electrochemistry, and Fourier-transform infrared spectroscopy to describe a protein morphing mechanism that controls the reversible transition between the catalytic Hox-state and the inactive but oxygen-resistant Hinact-state in [FeFe]-hydrogenase CbA5H of Clostridium beijerinckii. The X-ray structure of air-exposed CbA5H reveals that a conserved cysteine residue in the local environment of the active site (H-cluster) directly coordinates the substrate-binding site, providing a safety cap that prevents O2-binding and consequently, cofactor degradation. This protection mechanism depends on three non-conserved amino acids situated approximately 13 Å away from the H-cluster, demonstrating that the 1st coordination sphere chemistry of the H-cluster can be remote-controlled by distant residues.