Cloned (Comment) | Organism |
---|---|
expression of N-terminally His-tagged wild-type and mutant enzymes in Escherichia coli | Hypericum androsaemum |
Protein Variants | Comment | Organism |
---|---|---|
T135L | the T135L mutant catalyzes the addition of only two acetyl groups to the benzoyl starter unit. The triketide is the final linear intermediate and cyclizes into phenylpyrone via C-5 keto-enol oxygen -> C-1 lactonization. The T135L substitution opens a new pocket, the entrance of which is blocked in the wild-type enzyme by hydrogen bond formation between the threonine side chain and the backbone. Because of the interaction of the lipophilic side chain of the introduced leucine residue with the phenyl group of the growing polyketide chain, the triketide in the active site cavity of the T135L mutant may be redirected into the new pocket | Hypericum androsaemum |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.001 | - |
benzoyl-CoA | pH 7.0, 35°C, mutant T135L enzyme | Hypericum androsaemum | |
0.0086 | - |
benzoyl-CoA | pH 7.0, 35°C, wild-type enzyme | Hypericum androsaemum | |
0.0087 | - |
malonyl-CoA | pH 7.0, 35°C, mutant T135L enzyme | Hypericum androsaemum | |
0.0313 | - |
malonyl-CoA | pH 7.0, 35°C, wild-type enzyme | Hypericum androsaemum |
Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
---|---|---|---|
42800 | - |
2 * 42800 | Hypericum androsaemum |
85000 | - |
- |
Hypericum androsaemum |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
3 malonyl-CoA + benzoyl-CoA | Hypericum androsaemum | - |
4 CoA + 2,4,6-trihydroxybenzophenone + 3 CO2 | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Hypericum androsaemum | - |
- |
- |
Purification (Comment) | Organism |
---|---|
reccombinant N-terminally His-tagged wild-type and mutant enzymes from Escherichia coli by nickel affinity chromatography | Hypericum androsaemum |
Reaction | Comment | Organism | Reaction ID |
---|---|---|---|
3 malonyl-CoA + benzoyl-CoA = 4 CoA + 2,4,6-trihydroxybenzophenone + 3 CO2 | the enzyme catalyzes the iterative condensation of benzoyl-CoA with three molecules of malonyl-CoA to give a linear tetraketide intermediate, which is subsequently cyclized into 2,4,6-trihydroxybenzophenone via intramolecular Claisen condensation, catalytic mechanism, overview | Hypericum androsaemum |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
2 malonyl-CoA + benzoyl-CoA | reaction of mutant T135L, no activity with the wild-type enzyme. The T135L mutant adds only two acetyl groups to the benzoyl starter unit to form a triketide intermediate which then cyclized into 6-phenyl-4-hydroxy-2-pyrone via C5 keto-enol oxygen -> C1 lactonization | Hypericum androsaemum | 3 CoA + 6-phenyl-4-hydroxy-2-pyrone + 2 CO2 | - |
? | |
3 malonyl-CoA + benzoyl-CoA | - |
Hypericum androsaemum | 4 CoA + 2,4,6-trihydroxybenzophenone + 3 CO2 | - |
? | |
3 malonyl-CoA + benzoyl-CoA | benzoyl-CoA is the preferred starter substrate of the wild-type enzyme, activity by wild-type enzyme and mutant T135L | Hypericum androsaemum | 4 CoA + 2,4,6-trihydroxybenzophenone + 3 CO2 | - |
? | |
additional information | 3-hydroxybenzoyl-CoA is the second best starter substrate for the wild-type enzyme but a poor starter molecule for the mutant enzyme T135L, resulting in formation of 2,3',4,6-tetrahydroxybenzophenone, reaction of EC 2.3.1.151. Product identification by mass spectrometry. No activity by wild-type enzyme and mutant T135L with 2-hydroxybenzoyl-CoA, 4-hydroxybenzoyl-CoA, cinnamoyl-CoA, 2-coumaroyl-CoA, 3-coumaroyl-CoA, 4-coumaroyl-CoA, and acetyl-CoA | Hypericum androsaemum | ? | - |
? |
Subunits | Comment | Organism |
---|---|---|
homodimer | 2 * 42800 | Hypericum androsaemum |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
35 | - |
- |
Hypericum androsaemum |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.0068 | - |
malonyl-CoA | pH 7.0, 35°C, mutant T135L enzyme | Hypericum androsaemum | |
0.0068 | - |
benzoyl-CoA | pH 7.0, 35°C, mutant T135L enzyme | Hypericum androsaemum | |
0.055 | - |
malonyl-CoA | pH 7.0, 35°C, wild-type enzyme | Hypericum androsaemum | |
0.055 | - |
benzoyl-CoA | pH 7.0, 35°C, wild-type enzyme | Hypericum androsaemum |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
6.5 | 7 | - |
Hypericum androsaemum |
Organism | Comment | pI Value Maximum | pI Value |
---|---|---|---|
Hypericum androsaemum | - |
- |
5.78 |
General Information | Comment | Organism |
---|---|---|
evolution | BPS is a type III polyketide synthase, PKS, and part of the chalcone synthase group of the superfamily of enzymes | Hypericum androsaemum |
malfunction | the T135L mutant catalyzes the addition of only two acetyl groups to the benzoyl starter unit. The triketide is the final linear intermediate and cyclizes into phenylpyrone via C-5 keto-enol oxygen -> C-1 lactonization | Hypericum androsaemum |
additional information | residues involved in the initiation pocket are M217, I258, A260, and Y269, and in the elongation pocket T135, S136, T197, M199, T200, S219, M267, and G342, the catalytic triad is formed by residues C167, H307, and N340, molecular modeling constructed based on the crystal structure of Medicago sativa CHS2 complexed with resveratrol, PDB ID 1CGZ, overview | Hypericum androsaemum |
kcat/KM Value [1/mMs-1] | kcat/KM Value Maximum [1/mMs-1] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.0064 | - |
malonyl-CoA | pH 7.0, 35°C, wild-type enzyme | Hypericum androsaemum | |
0.0064 | - |
benzoyl-CoA | pH 7.0, 35°C, wild-type enzyme | Hypericum androsaemum | |
0.0068 | - |
malonyl-CoA | pH 7.0, 35°C, mutant T135L enzyme | Hypericum androsaemum | |
0.0068 | - |
benzoyl-CoA | pH 7.0, 35°C, mutant T135L enzyme | Hypericum androsaemum |