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X-ray structure of Na+-NQR from Vibrio cholerae at 3.5 A resolution
Structural highlights
FunctionNQRA_VIBC3 NQR complex catalyzes the reduction of ubiquinone-1 to ubiquinol by two successive reactions, coupled with the transport of Na(+) ions from the cytoplasm to the periplasm. NqrA to NqrE are probably involved in the second step, the conversion of ubisemiquinone to ubiquinol.[HAMAP-Rule:MF_00425] Publication Abstract from PubMedIn the respiratory chain, NADH oxidation is coupled to ion translocation across the membrane to build up an electrochemical gradient. In the human pathogen Vibrio cholerae, the sodium-pumping NADH:quinone oxidoreductase (Na(+)-NQR) generates a sodium gradient by a so far unknown mechanism. Here we show that ion pumping in Na(+)-NQR is driven by large conformational changes coupling electron transfer to ion translocation. We have determined a series of cryo-EM and X-ray structures of the Na(+)-NQR that represent snapshots of the catalytic cycle. The six subunits NqrA, B, C, D, E, and F of Na(+)-NQR harbor a unique set of cofactors that shuttle the electrons from NADH twice across the membrane to quinone. The redox state of a unique intramembranous [2Fe-2S] cluster orchestrates the movements of subunit NqrC, which acts as an electron transfer switch. We propose that this switching movement controls the release of Na(+) from a binding site localized in subunit NqrB. Conformational coupling of redox-driven Na(+)-translocation in Vibrio cholerae NADH:quinone oxidoreductase.,Hau JL, Kaltwasser S, Muras V, Casutt MS, Vohl G, Claussen B, Steffen W, Leitner A, Bill E, Cutsail GE 3rd, DeBeer S, Vonck J, Steuber J, Fritz G Nat Struct Mol Biol. 2023 Nov;30(11):1686-1694. doi: 10.1038/s41594-023-01099-0. , Epub 2023 Sep 14. PMID:37710014[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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