Publication Date:
2014-12-05
Description:
NADH oxidation in the respiratory chain is coupled to ion translocation across the membrane to build up an electrochemical gradient. The sodium-translocating NADH:quinone oxidoreductase (Na(+)-NQR), a membrane protein complex widespread among pathogenic bacteria, consists of six subunits, NqrA, B, C, D, E and F. To our knowledge, no structural information on the Na(+)-NQR complex has been available until now. Here we present the crystal structure of the Na(+)-NQR complex at 3.5 A resolution. The arrangement of cofactors both at the cytoplasmic and the periplasmic side of the complex, together with a hitherto unknown iron centre in the midst of the membrane-embedded part, reveals an electron transfer pathway from the NADH-oxidizing cytoplasmic NqrF subunit across the membrane to the periplasmic NqrC, and back to the quinone reduction site on NqrA located in the cytoplasm. A sodium channel was localized in subunit NqrB, which represents the largest membrane subunit of the Na(+)-NQR and is structurally related to urea and ammonia transporters. On the basis of the structure we propose a mechanism of redox-driven Na(+) translocation where the change in redox state of the flavin mononucleotide cofactor in NqrB triggers the transport of Na(+) through the observed channel.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Steuber, Julia -- Vohl, Georg -- Casutt, Marco S -- Vorburger, Thomas -- Diederichs, Kay -- Fritz, Gunter -- England -- Nature. 2014 Dec 4;516(7529):62-7. doi: 10.1038/nature14003.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology, Garbenstrasse 30, University of Hohenheim, 70599 Stuttgart, Germany. ; 1] Institute for Neuropathology, University of Freiburg, Breisacher Strasse 64, 79106 Freiburg, Germany [2] Hermann-Staudinger-Graduate school, University of Freiburg, Hebelstrasse 27, 79104 Freiburg, Germany. ; Institute for Neuropathology, University of Freiburg, Breisacher Strasse 64, 79106 Freiburg, Germany. ; Department of Biology, University of Konstanz, Universitatsstrasse 10, 78457 Konstanz, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25471880" target="_blank"〉PubMed〈/a〉
Keywords:
Bacterial Proteins/*chemistry
;
Binding Sites
;
Crystallization
;
Crystallography, X-Ray
;
Flavoproteins/chemistry
;
Iron/chemistry
;
*Models, Molecular
;
NAD(P)H Dehydrogenase (Quinone)/*chemistry
;
Protein Interaction Domains and Motifs
;
Protein Structure, Tertiary
;
Protein Subunits/chemistry
;
Sodium/*chemistry
;
Sodium Channels/chemistry
;
Vibrio cholerae/*enzymology
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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