Functional and structural insights into O2-adapted hydrogenases

Résumé :

Hydrogenases are metalloenzymes that catalyse the interconversion of protons and electrons into molecular hydrogen (H₂), providing valuable models for robust and sustainable H₂ catalysts. However, most characterised hydrogenases are inhibited by oxygen (O₂), limiting their biotechnological potential. Although diverse [NiFe]- and [FeFe]-hydrogenases have evolved adaptations that support activity, stability, or recovery following O₂ exposure, the molecular basis of O₂ adaptation remains poorly understood.

In this talk, I will present our ongoing work on O₂-adapted hydrogenases from bacteria and archaea inhabiting aerobic soils, thermoacidophilic environments, and the gut. By combining physiological, biochemical, structural, and computational approaches, we investigate how distinct hydrogenase lineages support H2 metabolism under oxygen-exposed conditions.
These systems include the high-affinity group 1h [NiFe]-hydrogenase from Mycobacterium smegmatis, the Sulfolobales clade 2 [NiFe]-hydrogenase from Metallosphaera sedula, and gut microbial [FeFe]-hydrogenases, including group B enzymes from Bacteroides species and a group A1 enzyme from Clostridium perfringens. Together, they highlight the diversity of hydrogenase architectures, cofactor arrangements, and electron-transfer strategies that may contribute to O₂ resilience.

Overall, this work expands the functional and structural repertoire of O₂-adapted hydrogenases, informing our understanding of microbial H2 metabolism and the search for enzymes suited to H₂-based biocatalysis.

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