Cloned (Comment) | Organism |
---|---|
sequence comparison | Rheum palmatum |
Protein Variants | Comment | Organism |
---|---|---|
C197G | site-directed mutagenesis, the mutant shows an unaltered product pattern compared to the wild-type enzyme | Rheum palmatum |
C197T | site-directed mutagenesis, the mutant shows an unaltered product pattern compared to the wild-type enzyme | Rheum palmatum |
G256L | site-directed mutagenesis, the mutant shows 50% reduced activity but an unaltered product pattern compared to the wild-type enzyme | Rheum palmatum |
I214L/L215F | site-directed mutagenesis, the mutant restores chalcone-forming activity | Rheum palmatum |
additional information | formation of other products such as a tetraketide pyrone 4-coumaroyltriacetic acid lactone or naringenin chalcone is not detected for all the mutant enzymes | Rheum palmatum |
S338V | site-directed mutagenesis, the mutant shows 2fold increased activity but an unaltered product pattern compared to the wild-type enzyme | Rheum palmatum |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
4-coumaroyl-CoA + malonyl-CoA + H2O | Rheum palmatum | - |
2 CoA + 4-hydroxybenzalacetone + 2 CO2 | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Rheum palmatum | Q94FV7 | - |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
4-coumaroyl-CoA + malonyl-CoA + H2O | - |
Rheum palmatum | 2 CoA + 4-hydroxybenzalacetone + 2 CO2 | - |
? | |
4-coumaroyl-CoA + malonyl-CoA + H2O | a one-step decarboxylative condensation at pH 8.0 | Rheum palmatum | 2 CoA + 4-hydroxybenzalacetone + 2 CO2 | i.e. 4-(4-hydroxyphenyl)but-3-en-2-one | ? | |
4-coumaroylCoA + 2 malonyl-CoA + H2O | wild-type and mutant BAS all afford the triketide pyrone bisnoryangonin after two condensations with malonyl-CoA at acidic pH 6.0 | Rheum palmatum | 2 CoA + bisnoryangonin + 2 CO2 | - |
? | |
additional information | the wild-type enzyme also shows formation of benzalacetone, bisnoryangonin, and naringenin chalcone from 4-coumaroyl-CoA and malonyl-CoA as substrates, cf. EC 2.3.1.74, as well as formation of triacetic acid lactone, 5,7-dihydroxy-2-methylchromone, and 2,7-dihydroxy-5-[(4-hydroxy-2-oxo-2H-pyran-6-yl)methyl]-2-methyl-2,3-dihydro-4H-chromen-4-one (SEK4) and 2,7-dihydroxy-5-[(4-hydroxy-2-oxo-2H-pyran-6-yl)methyl]-5-methyl-2,3-dihydro-4H-chromen-4-one (SEK4b), from malonyl-CoA as a substrate, mechanisms, overview | Rheum palmatum | ? | - |
? |
Subunits | Comment | Organism |
---|---|---|
More | homology modeling, overview | Rheum palmatum |
Synonyms | Comment | Organism |
---|---|---|
bAS | - |
Rheum palmatum |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
6 | - |
maximum for bisnoryangonin formation activity | Rheum palmatum |
8 | - |
maximum for benalacetone formation activity | Rheum palmatum |
General Information | Comment | Organism |
---|---|---|
evolution | the enzyme is a plant-specific type III polyketide synthase of the chalcone synthase (CHS) superfamily | Rheum palmatum |
additional information | pH-dependence of benzalacetone and bisnoryangonin production. Residues Ile214 and Leu215 are responsible for the diketide formation activity, unlike the case of CHS with residues L214 and F215, BAS utilizes an alternative pocket to lock the coumaroyl moiety for the diketide formation reaction, the second active-site Cys is not involved in the enzyme reaction,and Cys197 is not essential for the 4-hydroxybenzalacetone-producing activity, homology modeling | Rheum palmatum |