Any feedback?
Literature summary extracted from
- The electron transfer pathway of the Na+-pumping NADH:Quinone Oxidoreductase from Vibrio cholerae (2009), J. Biol. Chem., 284, 8963-8972.
Activating Compound
| EC Number | Activating Compound | Comment | Organism | Structure |
|---|---|---|---|---|
| 7.2.1.1 | FAD | enzyme contains a 2Fe-2S center. Electrons flow from NADH to quinone through the FAD in subunit F, the 2Fe-2S center, the FMN in subunit C, the FMN in subunit B, and finally riboflavin. The reduction of the FMN(C) to its anionic flavosemiquinone state is the first Na+-dependent process, suggesting that reduction of this site is linked to Na+ uptake. During the reduction reaction, two FMNs are transformed to their anionic flavosemiquinone in a single kinetic step. Subsequently, FMN(C) is converted to the flavohydroquinone, accounting for the single anionic flavosemiquinone radical in the fully reduced enzyme | Vibrio cholerae serotype O1 |  |
| 7.2.1.1 | FMN | enzyme contains a 2Fe-2S center. Electrons flow from NADH to quinone through the FAD in subunit F, the 2Fe-2S center, the FMN in subunit C, the FMN in subunit B, and finally riboflavin. The reduction of the FMN(C) to its anionic flavosemiquinone state is the first Na+-dependent process, suggesting that reduction of this site is linked to Na+ uptake. During the reduction reaction, two FMNs are transformed to their anionic flavosemiquinone in a single kinetic step. Subsequently, FMN(C) is converted to the flavohydroquinone, accounting for the single anionic flavosemiquinone radical in the fully reduced enzyme | Vibrio cholerae serotype O1 | |
Protein Variants
| EC Number | Protein Variants | Comment | Organism |
|---|---|---|---|
| 7.2.1.1 | C76A | in the NqrF-C76A mutant, turnover with ferricyanide is almost the same as in the wild type enzyme | Vibrio cholerae serotype O1 |
| 7.2.1.1 | C76A | in this mutant one of the cysteine ligands of the 2Fe-2S center is changed to alanine, resulting in the complete loss of this cofactor. In all three flavin mutants (NqrB-T236Y, NqrCT225Y, and the double mutant) as well as the 2Fe-2S center mutant (NqrF-C76A), the reduction by NADH of the neutral flavosemiquinone is dramatically slowed, or abolished, compared with the wild type enzyme | Vibrio cholerae serotype O1 |
| 7.2.1.1 | C76A | mutant lacks the 2Fe-2S center in NqrF (NqrF-C76A). The reaction of the mutant enzyme with NADH consists of a single phase, whether or not Na+ is present. Turnover with ferricyanide is almost the same as in the wild type enzyme. Two electron reduction of a flavin is the only significant phase remaining from the wild type reaction, allows the redox carrier upstream of the 2Fe-2S center to be assigned to the first kinetic phase of the wild type reaction and hence to the FAD in NqrF. Reduction by NADH of the neutral flavosemiquinone is strongly slowed or abolished, compared with the wild type enzyme | Vibrio cholerae serotype O1 |
| 7.2.1.1 | S246A | the wild type enzyme is capable of transferring electrons from NADH to ferricyanide. This reaction is almost completely abolished in the NqrFS246A mutant, which lacks the FAD | Vibrio cholerae serotype O1 |
| 7.2.1.1 | S246A | this reaction is almost completely abolished in the NqrFS246A mutant, which lacks the FAD | Vibrio cholerae serotype O1 |
| 7.2.1.1 | T225Y | in all three flavin mutants (NqrB-T236Y, NqrCT225Y, and the double mutant) as well as the 2Fe-2S center mutant (NqrF-C76A), the reduction by NADH of the neutral flavosemiquinone is dramatically slowed, or abolished, compared with the wild type enzyme | Vibrio cholerae serotype O1 |
| 7.2.1.1 | T225Y | mutant lacks FMN in subunit C (NqrC-T225Y). Reduction by NADH of the neutral flavosemiquinone is strongly slowed or abolished, compared with the wild type enzyme | Vibrio cholerae serotype O1 |
| 7.2.1.1 | T236Y | in all three flavin mutants (NqrB-T236Y, NqrCT225Y, and the double mutant) as well as the 2Fe-2S center mutant (NqrF-C76A), the reduction by NADH of the neutral flavosemiquinone is dramatically slowed, or abolished, compared with the wild type enzyme | Vibrio cholerae serotype O1 |
| 7.2.1.1 | T236Y | mutant lacks FMN in subunit B (NqrB-T236Y). Reduction by NADH of the neutral flavosemiquinone is strongly slowed or abolished, compared with the wild type enzyme | Vibrio cholerae serotype O1 |
| 7.2.1.1 | T236Y/T225Y | in all three flavin mutants (NqrB-T236Y, NqrCT225Y, and the double mutant) as well as the 2Fe-2S center mutant (NqrF-C76A), the reduction by NADH of the neutral flavosemiquinone is dramatically slowed, or abolished, compared with the wild type enzyme | Vibrio cholerae serotype O1 |
| 7.2.1.1 | T236Y/T225Y | mutant lacks FMN in subunit B and FMN in subunit C (NqrB-T236Y/NqrC-T225Y). This mutant contains only the noncovalently bound FAD in NqrF and the noncovalently bound riboflavin. The reaction of the mutant enzyme with NADH consists of a single phase, whether or not Na+ is present. The rate constants are almost identical, are as the spectra. The spectra appear to show two-electron reduction of a flavin. The spectra and rates are consistent with those of the first phase of the reaction of the wild type enzyme in the absence of Na+. Reduction by NADH of the neutral flavosemiquinone is strongly slowed or abolished, compared with the wild type enzyme | Vibrio cholerae serotype O1 |
Metals/Ions
| EC Number | Metals/Ions | Comment | Organism | Structure |
|---|---|---|---|---|
| 7.2.1.1 | Fe | enzyme contains a 2Fe-2S center. Electrons flow from NADH to quinone through the FAD in subunit F, the 2Fe-2S center, the FMN in subunit C, the FMN in subunit B, and finally riboflavin. The reduction of the FMN(C) to its anionic flavosemiquinone state is the first Na+-dependent process, suggesting that reduction of this site is linked to Na+ uptake. During the reduction reaction, two FMNs are transformed to their anionic flavosemiquinone in a single kinetic step. Subsequently, FMN(C) is converted to the flavohydroquinone, accounting for the single anionic flavosemiquinone radical in the fully reduced enzyme | Vibrio cholerae serotype O1 | |
| 7.2.1.1 | Fe | the enzyme contains one 2Fe-2S center, electrons flow from NADH to quinone through the FAD in subunit F, the 2Fe-2S center, the FMN in subunit C, the FMN in subunit B, and finally riboflavin. The reduction of the FMN(C) to its anionic flavosemiquinone state is the first Na+-dependent process, suggesting that reduction of this site is linked to Na+ uptake. During the reduction reaction, two FMNs are transformed to their anionic flavosemiquinone in a single kinetic step. Subsequently, FMN(C) is converted to the flavohydroquinone, accounting for the single anionic flavosemiquinone radical in the fully reduced enzyme | Vibrio cholerae serotype O1 | |
Natural Substrates/ Products (Substrates)
| EC Number | Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|---|
| 7.2.1.1 | NADH + H+ + ubiquinone | Vibrio cholerae serotype O1 | the Na+-pumping NADH:ubiquinone oxidoreductase is a molecular energy transducer present in the membrane of many marine and pathogenic bacteria. The enzyme accepts electrons from NADH and donates them to ubiquinone. This redox reaction releases a significant amount of energy, which is used to pump Na+ across the cell membrane, creating a Na+ gradient as well as an electrical potential. Electrons flow from NADH to quinone through the FAD in subunit F, the 2Fe-2S center, the FMN in subunit C, the FMN in subunit B, and finally riboflavin. The reduction of the FMN(C) to its anionic flavosemiquinone state is the first Na+-dependent process, suggesting that reduction of this site is linked to Na+ uptake. During the reduction reaction, two FMNs are transformed to their anionic flavosemiquinone in a single kinetic step. Subsequently, FMN(C) is converted to the flavohydroquinone, accounting for the single anionic flavosemiquinone radical in the fully reduced enzyme | NAD+ + ubiquinol | - |
? | |
Organism
| EC Number | Organism | UniProt | Comment | Textmining |
|---|---|---|---|---|
| 7.2.1.1 | Vibrio cholerae serotype O1 | - |
- |
- |
Purification (Commentary)
| EC Number | Purification (Comment) | Organism |
|---|---|---|
| 7.2.1.1 | wild type and mutant Na+-NQR proteins | Vibrio cholerae serotype O1 |
Substrates and Products (Substrate)
| EC Number | Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|---|
| 7.2.1.1 | NADH + H+ + ubiquinone | the Na+-pumping NADH:ubiquinone oxidoreductase is a molecular energy transducer present in the membrane of many marine and pathogenic bacteria. The enzyme accepts electrons from NADH and donates them to ubiquinone. This redox reaction releases a significant amount of energy, which is used to pump Na+ across the cell membrane, creating a Na+ gradient as well as an electrical potential. Electrons flow from NADH to quinone through the FAD in subunit F, the 2Fe-2S center, the FMN in subunit C, the FMN in subunit B, and finally riboflavin. The reduction of the FMN(C) to its anionic flavosemiquinone state is the first Na+-dependent process, suggesting that reduction of this site is linked to Na+ uptake. During the reduction reaction, two FMNs are transformed to their anionic flavosemiquinone in a single kinetic step. Subsequently, FMN(C) is converted to the flavohydroquinone, accounting for the single anionic flavosemiquinone radical in the fully reduced enzyme | Vibrio cholerae serotype O1 | NAD+ + ubiquinol | - |
? | |
| 7.2.1.1 | NADH + H+ + ubiquinone | electrons flow from NADH to quinone through the FAD in subunit F, the 2Fe-2S center, the FMN in subunit C, the FMN in subunit B, and finally riboflavin. The reduction of the FMN(C) to its anionic flavosemiquinone state is the first Na+-dependent process, suggesting that reduction of this site is linked to Na+ uptake. During the reduction reaction, two FMNs are transformed to their anionic flavosemiquinone in a single kinetic step. Subsequently, FMN(C) is converted to the flavohydroquinone, accounting for the single anionic flavosemiquinone radical in the fully reduced enzyme | Vibrio cholerae serotype O1 | NAD+ + ubiquinol | - |
? | |
| 7.2.1.1 | NADH + H+ + ubiquinone | the results on the reverse reaction, in which the oxidized enzyme takes electrons from quinol, confirm that riboflavin, the center that gives rise to the neutral flavosemiquinone, is located downstream of both FMNB and FMNC in the forward pathway. Riboflavin is likely to be the site from which electrons are donated to quinone during enzyme turnover | Vibrio cholerae serotype O1 | NAD+ + ubiquinol | - |
r | |
Synonyms
| EC Number | Synonyms | Comment | Organism |
|---|---|---|---|
| 7.2.1.1 | Na+-NQR | - |
Vibrio cholerae serotype O1 |
| 7.2.1.1 | Na+-pumping NADH:quinone oxidoreductase | - |
Vibrio cholerae serotype O1 |
Cofactor
| EC Number | Cofactor | Comment | Organism | Structure |
|---|---|---|---|---|
| 7.2.1.1 | FAD | electrons flow from NADH to quinone through the FAD in subunit F, the 2Fe-2S center, the FMN in subunit C, the FMN in subunit B, and finally riboflavin. The reduction of the FMN(C) to its anionic flavosemiquinone state is the first Na+-dependent process, suggesting that reduction of this site is linked to Na+ uptake. During the reduction reaction, two FMNs are transformed to their anionic flavosemiquinone in a single kinetic step. Subsequently, FMN(C) is converted to the flavohydroquinone, accounting for the single anionic flavosemiquinone radical in the fully reduced enzyme | Vibrio cholerae serotype O1 | |
| 7.2.1.1 | FMN | electrons flow from NADH to quinone through the FAD in subunit F, the 2Fe-2S center, the FMN in subunit C, the FMN in subunit B, and finally riboflavin. The reduction of the FMN(C) to its anionic flavosemiquinone state is the first Na+-dependent process, suggesting that reduction of this site is linked to Na+ uptake. During the reduction reaction, two FMNs are transformed to their anionic flavosemiquinone in a single kinetic step. Subsequently, FMN(C) is converted to the flavohydroquinone, accounting for the single anionic flavosemiquinone radical in the fully reduced enzyme | Vibrio cholerae serotype O1 | |
| 7.2.1.1 | NADH | - |
Vibrio cholerae serotype O1 | |
| 7.2.1.1 | riboflavin | electrons flow from NADH to quinone through the FAD in subunit F, the 2Fe-2S center, the FMN in subunit C, the FMN in subunit B, and finally riboflavin. The reduction of the FMN(C) to its anionic flavosemiquinone state is the first Na+-dependent process, suggesting that reduction of this site is linked to Na+ uptake. During the reduction reaction, two FMNs are transformed to their anionic flavosemiquinone in a single kinetic step. Subsequently, FMN(C) is converted to the flavohydroquinone, accounting for the single anionic flavosemiquinone radical in the fully reduced enzyme | Vibrio cholerae serotype O1 | |
Use of this online version of BRENDA is free under the CC BY 4.0 license. See terms of use for full details.
Release 2023.1 (January 2023)
Legal
Curated at
Member of
