Protein Variants | Comment | Organism |
---|---|---|
H187Y | mutant lacking heme bL but having heme bH, the heme reduction by menadiol is abolished | Escherichia coli |
H205Y | mutant without heme bH but with heme bL, a smaller and slower heme reduction compared to that of the wild-type enzyme is observed. A transient species, likely to be associated with a semiquinone radical anion, is generated not only on reduction of the wild-type enzyme but also on reduction of NarGHIH56R and NarGHIH205Y. Compared to the wild type, no significant heme reoxidation is observed for NarGHIH56R and NarGHIH205Y. This result indicates that a single mutation removing heme bH blocks the electron-transfer pathway from the subunit NarI to the catalytic dimer NarGH | Escherichia coli |
H56R | mutant without heme bH but with heme bL, a smaller and slower heme reduction compared to that of the wild-type enzyme is observed. A transient species, likely to be associated with a semiquinone radical anion, is generated not only on reduction of the wild-type enzyme but also on reduction of NarGHIH56R and NarGHIH205Y. Compared to the wild type, no significant heme reoxidation is observed for NarGHIH56R and NarGHIH205Y. This result indicates that a single mutation removing heme bH blocks the electron-transfer pathway from the subunit NarI to the catalytic dimer NarGH | Escherichia coli |
H66Y | mutant lacking heme bL but having heme bH, the heme reduction by menadiol is abolished | Escherichia coli |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
2-n-heptyl-4-hydroxyquinoline N-oxide | has significant effects on the reduction kinetics of NarGHIH56R and NarGHIH205Y | Escherichia coli | |
Stigmatellin | has significant effects on the reduction kinetics of NarGHIH56R and NarGHIH205Y | Escherichia coli |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Escherichia coli | - |
- |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
nitrate + 2-methyl-1,4-naphthoquinol | i.e. menadiol. Electrons from menadiol oxidation are transferred initially to heme bL | Escherichia coli | nitrite + 2-methyl-1,4-naphthoquinone + H2O | - |
? |
Synonyms | Comment | Organism |
---|---|---|
NarGHI | - |
Escherichia coli |
nitrate reductase A | - |
Escherichia coli |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
cytochrome bH | both heme bL and heme bH are crucial components in the electron-transfer pathway from the subunit NarI through subunit NarH to the catalytic subunit NarG. Without heme bL electrons cannot be transferred from menaquinol to heme bH. On the other hand, in the absence of heme bH, electrons cannot be transferred from the reduced heme bL to the catalytic dimer NarGH. A complex of menadione radical anion associated with the enzyme, is formed during the process of heme reduction by menadiol | Escherichia coli | |
cytochrome bL | both heme bL and heme bH are crucial components in the electron-transfer pathway from the subunit NarI through subunit NarH to the catalytic subunit NarG. Without heme bL electrons cannot be transferred from menaquinol to heme bH. On the other hand, in the absence of heme bH, electrons cannot be transferred from the reduced heme bL to the catalytic dimer NarGH. A complex of menadione radical anion associated with the enzyme, is formed during the process of heme reduction by menadiol | Escherichia coli |