ja1c09356_si_002.mpg (4.01 MB)
Functional Dynamics of an Ancient Membrane-Bound Hydrogenase
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posted on 2021-11-30, 21:07 authored by Max E. Mühlbauer, Ana P. Gamiz-Hernandez, Ville R. I. KailaThe membrane-bound
hydrogenase (Mbh) is a redox-driven Na+/H+ transporter
that employs the energy from hydrogen
gas (H2) production to catalyze proton pumping and Na+/H+ exchange across cytoplasmic membranes of archaea.
Despite a recently resolved structure of this ancient energy-transducing
enzyme [Yu et al. Cell 2018, 173, 1636–1649], the molecular principles of its
redox-driven ion-transport mechanism remain puzzling and of major
interest for understanding bioenergetic principles of early cells.
Here we use atomistic molecular dynamics (MD) simulations in combination
with data clustering methods and quantum chemical calculations to
probe principles underlying proton reduction as well as proton and
sodium transport in Mbh from the hyperthermophilic archaeon Pyrococcus furiosus. We identify putative Na+ binding sites and proton pathways leading across the membrane
and to the NiFe-active center as well as conformational changes that
regulate ion uptake. We suggest that Na+ binding and protonation
changes at a putative ion-binding site couple to proton transfer across
the antiporter-like MbhH subunit by modulating the conformational
state of a conserved ion pair at the subunit interface. Our findings
illustrate conserved coupling principles within the complex I superfamily
and provide functional insight into archaeal energy transduction mechanisms.
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yu et alsup >+ suprecently resolved structurequantum chemical calculationsdata clustering methodsunderstanding bioenergetic principlesregulate ion uptakeprovide functional insightlike mbhh subunitconserved ion pairproton transfer acrosscatalyze proton pumpingbinding site coupleidentify putative naputative ionsubunit interfacemolecular principlesfunctional dynamicsdriven iontransducing enzymesodium transportprotonation changesmajor interesthydrogen gasearly cellsdriven naconformational stateconformational changescell bound hydrogenasebinding sitesactive center173