Structure of the V. cholerae Na^sup +^-pumping NADH:quinone oxidoreductase

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^sup +^ - NQR), a membrane protein complex widespread among pathogenic bacteria, consists of six subunits,...

Full description

Saved in:
Bibliographic Details
Published in:Nature (London) 2014-12, Vol.516 (7529), p.62
Main Authors: Steuber, Julia, Vohl, Georg, Casutt, Marco S, Vorburger, Thomas, Diederichs, Kay, Fritz, Günter
Format: Article
Language:English
Subjects:
Bacteria
Bacteriology
Crystal structure
Cytoplasm
Electrochemistry
Membranes
Proteins
Sodium
Translocation
Urea
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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^sup +^ - 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^sup +^ -NQR complex has been available until now. Here we present the crystal structure of the Na^sup +^ -NQR complex at 3.5 Å 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^sup +^ - NQR and is structurally related to urea and ammonia transporters. On the basis of the structure we propose a mechanism of redox-driven Na^sup +^ translocation where the change in redox state of the flavin mononucleotide cofactor in NqrB triggers the transport of Na1 through the observed channel.
ISSN:0028-0836
1476-4687