Archaeal genomes used in the study "<b>Unique minimal and hybrid hydrogenases are active from anaerobic archaea</b>".

<br><b>Unique minimal and hybrid hydrogenases are active from anaerobic archaea</b>Chris Greening^1,9 *<b> </b>^#<b>, </b>Princess R. Cabotaje² ^#, Luis E. Valentin Alvarado^{3 #}, Pok Man Leung^{1 #}, Henrik Land², Thiago Rodrigues-Oliveira⁴, Rafael I. Ponce-Toledo⁴, Moritz Senger², Max A. Klamke², Michael Milton¹, Rachael Lappan¹, Susan Mullen³, Jacob West-Roberts³, Jie Mao^1,5, Jiangning Song⁵, Marie Schoelmerich³, Courtney W. Stairs⁶, Christa Schleper⁴, Rhys Grinter¹ *,Anja Spang^7,8*, Jillian F. Banfield^1,3 *, Gustav Berggren² *<br><b>Summary</b>Microbial hydrogen (H₂) cycling underpins the diversity and functionality of diverse anoxic ecosystems. Among the three evolutionarily distinct hydrogenase superfamilies responsible, [FeFe]-hydrogenases were thought to be restricted to bacteria and eukaryotes. Here we show that anaerobic archaea encode diverse, active, and ancient lineages of [FeFe]-hydrogenases through combining analysis of existing and new genomes with extensive biochemical experiments. [FeFe]-hydrogenases are encoded by genomes of nine archaeal phyla and expressed by H₂-producing Asgard archaeon cultures. We report a novel ultra-minimal hydrogenase in DPANN archaea that binds the catalytic H-cluster and produces H₂. Moreover, we identified and characterised remarkable hybrid complexes formed through the fusion of [FeFe]- and [NiFe]-hydrogenases in ten other archaeal orders. Phylogenetic analysis and structural modelling suggest a deep evolutionary history of hybrid hydrogenases. These findings reveal new metabolic adaptations of archaea, streamlined H₂ catalysts for biotechnological development, and a surprisingly intertwined evolutionary history between the two major H₂-metabolizing enzymes.