Kumar, A.* ; Roth, J.* ; Kim, H.* ; Saura, P.* ; Bohn, S. ; Reif-Trauttmansdorff, T.* ; Schubert, A.* ; Kaila, V.R.I.* ; Schuller, J.M.* ; Müller, V.*
Molecular principles of redox-coupled sodium pumping of the ancient Rnf machinery.
Nat. Commun. 16:2302 (2025)
The Rnf complex is the primary respiratory enzyme of several anaerobic prokaryotes that transfers electrons from ferredoxin to NAD+ and pumps ions (Na+ or H+) across a membrane, powering ATP synthesis. Rnf is widespread in primordial organisms and the evolutionary predecessor of the Na+-pumping NADH-quinone oxidoreductase (Nqr). By running in reverse, Rnf uses the electrochemical ion gradient to drive ferredoxin reduction with NADH, providing low potential electrons for nitrogenases and CO2 reductases. Yet, the molecular principles that couple the long-range electron transfer to Na+ translocation remain elusive. Here, we resolve key functional states along the electron transfer pathway in the Na+-pumping Rnf complex from Acetobacterium woodii using redox-controlled cryo-electron microscopy that, in combination with biochemical functional assays and atomistic molecular simulations, provide key insight into the redox-driven Na+ pumping mechanism. We show that the reduction of the unique membrane-embedded [2Fe2S] cluster electrostatically attracts Na+, and in turn, triggers an inward/outward transition with alternating membrane access driving the Na+ pump and the reduction of NAD+. Our study unveils an ancient mechanism for redox-driven ion pumping, and provides key understanding of the fundamental principles governing energy conversion in biological systems.
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Publikationstyp
Artikel: Journalartikel
Dokumenttyp
Wissenschaftlicher Artikel
Typ der Hochschulschrift
Herausgeber
Schlagwörter
Rhodobacter-capsulatus; Acetobacterium-woodii; Nitrogen-fixation; Identification; Oxidoreductase; Quantitation; Transport; Model; Na+; Ion
Keywords plus
Sprache
englisch
Veröffentlichungsjahr
2025
Prepublished im Jahr
0
HGF-Berichtsjahr
2025
ISSN (print) / ISBN
2041-1723
e-ISSN
2041-1723
ISBN
Bandtitel
Konferenztitel
Konferzenzdatum
Konferenzort
Konferenzband
Quellenangaben
Band: 16,
Heft: 1,
Seiten: ,
Artikelnummer: 2302
Supplement: ,
Reihe
Verlag
Nature Publishing Group
Verlagsort
London
Tag d. mündl. Prüfung
0000-00-00
Betreuer
Gutachter
Prüfer
Topic
Hochschule
Hochschulort
Fakultät
Veröffentlichungsdatum
0000-00-00
Anmeldedatum
0000-00-00
Anmelder/Inhaber
weitere Inhaber
Anmeldeland
Priorität
Begutachtungsstatus
Peer reviewed
Institut(e)
Cryo-EM facility (CEMP)
POF Topic(s)
30201 - Metabolic Health
Forschungsfeld(er)
PSP-Element(e)
G-510098-001
Förderungen
Leibniz-Rechenzentrum (LRZ)
DFG
European Union
German Research Foundation (DFG)
European Research Council under the European Union
Swedish Research Council
Knut and Alice Wallenberg (KAW) Foundation
EC | EU Framework Programme for Research and Innovation H2020 | H2020 Priority Excellent Science | H2020 European Research Council (H2020 Excellent Science - European Research Council)
Copyright
Erfassungsdatum
2025-03-10