Molecular principles of redox-coupled sodium pumping of the ancient Rnf machinery.

ABSTRACT: 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 compl

SUBMITTER: Kumar A 

PROVIDER: S-EPMC11889175 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature