FEATURES

FAMILY

DESCRIPTION

Also known as NQO9_THET8, nqo9. NDH-1 shuttles electrons from NADH, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory chain. The immediate electron acceptor for the enzyme in this species is menaquinone. Couples the redox reaction to proton translocation (for every two electrons transferred, four hydrogen ions are translocated across the cytoplasmic membrane), and thus conserves the redox energy in a proton gradient required for the synthesis of ATP. The role of the Nqo9 subunit appears to provide a 'connecting chain' of two clusters between cluster N5 and the terminal cluster N2, and to stabilize the structure of the complex by interacting with other subunits. NDH-1 is composed of 15 different subunits, Nqo1 to Nqo15. The complex has a L-shaped structure, with the hydrophobic arm (subunits Nqo7, Nqo8 and Nqo10 to Nqo14) embedded in the membrane and the hydrophilic peripheral arm (subunits Nqo1 to Nqo6, Nqo9 and Nqo15) protruding into the bacterial cytoplasm. The hydrophilic domain contains all the redox centers.

EXTERNAL LINKS

nqo9

NADH-quinone oxidoreductase subunit 9

nqo9

Molecular Synopsis