Recombinant Rhizobium meliloti NADH-quinone oxidoreductase subunit A 1 (nuoA1)
Description
Structure and Composition
NDH-1 is a large multi-subunit enzyme complex. The bacterial NDH-1, found in organisms like Paracoccus denitrificans and Thermus thermophilus, consists of 14 subunits . The mitochondrial enzyme in mammals contains over 40 subunits . In Paracoccus denitrificans, the NDH-1 complex comprises at least 14 subunits (NQO1-14) .
Function and Mechanism
NDH-1 catalyzes the transfer of electrons from NADH to the quinone pool in the cytoplasmic membrane . This process is coupled with the generation of a proton electrochemical gradient . The enzyme works with almost equal efficiency with the cofactors NADH and NADPH . During catalysis, a tightly bound FAD cofactor is reduced by NAD(P)H in the first stage of a substituted enzyme mechanism .
NuoA1 Subunit
The NuoA1 subunit is a component of the NDH-1 complex. Research indicates that the PSST subunit, homologous to NQO6 in bacteria, plays a crucial role in electron transfer by functionally coupling iron-sulfur cluster N2 to quinone .
Quinone Oxidoreductase
NAD(P)H quinone oxidoreductase 1 (NQO1) is an intracellular, cytosolic enzyme that catalyzes the reduction of quinones and a variety of other compounds . NQO1 is a homodimer with two active sites located at the interface between the subunits .
Inhibitors
Dicoumarol is a potent inhibitor of NQO1 . Other inhibitors of NDH-1 include rotenone, piericidin A, bullatacin, and pyridaben .
Role in Disease
Dysfunction of mitochondrial proton-translocating NADH-ubiquinone oxidoreductase (complex I) is associated with neurodegenerative disorders, such as Parkinson's disease and Huntington's disease . NQO1 is often over-expressed in cancer cells and is considered a possible drug target .
Resistance to Complex I Inhibition
Expression of the single-subunit NADH dehydrogenase of Saccharomyces cerevisiae (Ndi1P) can render mammalian nerve cells resistant to complex I inhibitors .
Rhizobium meliloti
Rhizobium meliloti is a bacterium known for its symbiotic relationship with legume roots, facilitating the development of nitrogen-fixing nodules . Rhizobium bacteria synthesize N-acylated beta-1,4-N-acetylglucosamine lipooligosaccharides, called Nod factors, which act as morphogenic signal molecules to legume roots during development of nitrogen-fixing nodules .
Tables
Table 1: Stoichiometry of Peripheral Subunits of P. denitrificans NDH-1
| Subunit | Stoichiometry |
|---|---|
| NQO1 | 1 |
| NQO2 | 1 |
| NQO3 | 1 |
| NQO4 | 1 |
| NQO5 | 1 |
| NQO9 | 1 |
Table 2: Partition Ratios for Inhibition of NQO1 by Indolequinones
| Compound | Partition Ratio |
|---|---|
| 5 | High |
| 16 | High |
| 24 | High |
| 8 | Not Determined |
| 20 | Not Determined |
| 27 | Near 1 |
| 12 | Near 1 |
| 28 | Near 1 |
| 13 | Near 1 |
| 29 | Near 1 |
| 14 | Near 1 |
Product Specs
Note: While we prioritize shipping the format currently in stock, please specify your format preference during order placement for customized preparation.
Note: All proteins are shipped with standard blue ice packs. Dry ice shipping requires advance notice and incurs additional charges.
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Target Background
NDH-1 facilitates electron transfer from NADH to quinones within the respiratory chain, utilizing FMN and iron-sulfur (Fe-S) centers as intermediates. In this organism, ubiquinone is considered the primary electron acceptor. The enzyme couples this redox reaction to proton translocation; four protons are translocated across the cytoplasmic membrane for every two electrons transferred, thereby conserving redox energy as a proton gradient.
KEGG: sme:SMc01912
STRING: 266834.SMc01912
