National Health and Medical Research Council (NHMRC, Australia)
APP1197376
オーストラリア
引用
ジャーナル: Nature / 年: 2023 タイトル: Structural basis for bacterial energy extraction from atmospheric hydrogen. 著者: Rhys Grinter / Ashleigh Kropp / Hari Venugopal / Moritz Senger / Jack Badley / Princess R Cabotaje / Ruyu Jia / Zehui Duan / Ping Huang / Sven T Stripp / Christopher K Barlow / Matthew ...著者: Rhys Grinter / Ashleigh Kropp / Hari Venugopal / Moritz Senger / Jack Badley / Princess R Cabotaje / Ruyu Jia / Zehui Duan / Ping Huang / Sven T Stripp / Christopher K Barlow / Matthew Belousoff / Hannah S Shafaat / Gregory M Cook / Ralf B Schittenhelm / Kylie A Vincent / Syma Khalid / Gustav Berggren / Chris Greening / 要旨: Diverse aerobic bacteria use atmospheric H as an energy source for growth and survival. This globally significant process regulates the composition of the atmosphere, enhances soil biodiversity and ...Diverse aerobic bacteria use atmospheric H as an energy source for growth and survival. This globally significant process regulates the composition of the atmosphere, enhances soil biodiversity and drives primary production in extreme environments. Atmospheric H oxidation is attributed to uncharacterized members of the [NiFe] hydrogenase superfamily. However, it remains unresolved how these enzymes overcome the extraordinary catalytic challenge of oxidizing picomolar levels of H amid ambient levels of the catalytic poison O and how the derived electrons are transferred to the respiratory chain. Here we determined the cryo-electron microscopy structure of the Mycobacterium smegmatis hydrogenase Huc and investigated its mechanism. Huc is a highly efficient oxygen-insensitive enzyme that couples oxidation of atmospheric H to the hydrogenation of the respiratory electron carrier menaquinone. Huc uses narrow hydrophobic gas channels to selectively bind atmospheric H at the expense of O, and 3 [3Fe-4S] clusters modulate the properties of the enzyme so that atmospheric H oxidation is energetically feasible. The Huc catalytic subunits form an octameric 833 kDa complex around a membrane-associated stalk, which transports and reduces menaquinone 94 Å from the membrane. These findings provide a mechanistic basis for the biogeochemically and ecologically important process of atmospheric H oxidation, uncover a mode of energy coupling dependent on long-range quinone transport, and pave the way for the development of catalysts that oxidize H in ambient air.