Protein Variants | Comment | Organism |
---|---|---|
F20L | growth on succinate is essentially the same as the wild-type, electron transfer activity, the apparent Km value for Q2 and the amount of azido-Q incorporated into the succinate dehydrogenase C subunit are comparable with those of the complement reductase, Phe-20 is not involved in the Q binding | Escherichia coli |
H30A | growth on succinate is essentially the same as the wild-type, electron transfer activity, the apparent Km value for Q2 and the amount of azido-Q incorporated into the succinate dehydrogenase C subunit are comparable with those of the complement reductase, His-30 is not involved in the Q binding | Escherichia coli |
R19A | growth on succinate is essentially the same as the wild-type, electron transfer activity, the apparent Km value for Q2 and the amount of azido-Q incorporated into the succinate dehydrogenase C subunit are comparable with those of the complement reductase, Arg-19 is not involved in the Q binding | Escherichia coli |
R31A | the mutation yield cells unable to grow aerobically in M9/succinate medium, the mutant has no activity, Arg-31 is a critical residue for succinate-Q-reductase | Escherichia coli |
R31H | the mutation yield cells unable to grow aerobically in M9/succinate medium, the mutant has no activity, the guanidino group of arginine is critical for succinate-Q reductase activity | Escherichia coli |
R31K | the mutation yield cells unable to grow aerobically in M9/succinate medium, the mutant has no activity, the guanidino group of arginine is critical for succinate-Q reductase activity, it occupies a much larger space than the primary amine of lysine, extends a longer distance, and may provide more chance for hydrogen bond formation, it may stabilize Q binding through pi-pi interactions between the guanidino group and the benzoquinone ring | Escherichia coli |
S27A | the mutation yield cells unable to grow aerobically in M9/succinate medium, the mutant has no activity, Ser-27 is a critical residue for succinate-Q-reductase, it participates in a hydrogen bond at the Q-binding site of the C subunit | Escherichia coli |
S27C | the mutation yield cells unable to grow aerobically in M9/succinate medium, the mutant has no activity, the size of the amino acid side chain at position 27 of C subunit is critical for Q binding | Escherichia coli |
S27T | the mutation yield cells unable to grow aerobically in M9/succinate medium, the mutant has no activity, the size of the amino acid side chain at position 27 of C subunit is critical for Q binding | Escherichia coli |
S33A | the mutant has retarded aerobic growth rate in succinate/M9 medium and it has 35% of the succinate-Q-reducase activity of complement enzyme, the apparent Km value of this mutant for Q2 is about the same as wild-type, the purified mutant protein has azido-Q uptake comparable with that of complement reductase, the mutation of Ser-33 to alanine may greatly reduce enzyme turnover without affecting the affinity for Q | Escherichia coli |
S33C | the mutant has retarded aerobic growth rate in succinate/M9 medium and it has 44% of the succinate-Q-reducase activity of complement enzyme, the apparent Km value of this mutant for Q2 is about the same as wild-type, the purified mutant protein has azido-Q uptake comparable with that of complement reductase | Escherichia coli |
S33T | the mutant has retarded aerobic growth rate in succinate/M9 medium and it has 88% of the succinate-Q-reducase activity of complement enzyme, the apparent Km value of this mutant for Q2 is about the same as wild-type, the purified mutant protein has azido-Q uptake comparable with that of complement reductase | Escherichia coli |
T17A | growth on succinate is essentially the same as the wild-type, electron transfer activity, the apparent Km value for Q2 and the amount of azido-Q incorporated into the succinate dehydrogenase C subunit are comparable with those of the complement reductase, Thr-17 is not involved in the Q binding | Escherichia coli |
T23A | the mutation yields cells capable of aerobic growth on M9/succinate medium at a rate slightly slower than that of complement strain, 40% decrease in the specific activity of the mutant to catalyze electron transfer from succinate to Q, apparent Km for Q2 is the same as that of complement reductase, Thr-23 may not be involved in Q binding | Escherichia coli |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.0089 | - |
ubiquinone-2 | S33C mutant | Escherichia coli | |
0.009 | - |
ubiquinone-2 | R19A and F20L mutants | Escherichia coli | |
0.01 | - |
ubiquinone-2 | S33T mutant | Escherichia coli | |
0.0102 | - |
ubiquinone-2 | T17A mutant | Escherichia coli | |
0.0106 | - |
ubiquinone-2 | H30A mutant | Escherichia coli | |
0.0108 | - |
ubiquinone-2 | wild-type and T23A mutant | Escherichia coli | |
0.0114 | - |
ubiquinone-2 | S33A mutant | Escherichia coli |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Escherichia coli | - |
succinate dehydrogenase | - |
Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
---|---|---|---|
additional information | - |
activities of wild-type and mutants, expressed in micromol of succinate oxidized/min/nmol of cytochrome b556 | Escherichia coli |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
succinate + 3-azido-2-methyl-5-methoxy-6-geranyl-1,4-benzoquinone | the succinate dehydrogenase C subunit is responsible for ubiquinone binding | Escherichia coli | fumarate + 3-azido-2-methyl-5-methoxy-6-geranyl-1,4-benzoquinol | - |
? | |
succinate + ubiquinone | - |
Escherichia coli | fumarate + ubiquinol | - |
? | |
succinate + ubiquinone-2 | - |
Escherichia coli | fumarate + ubiquinol | - |
r |