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Literature summary for 4.2.1.B20 extracted from
- Analysis of the catalytic mechanism of bifunctional triterpene/sesquarterpene cyclase Tyr167 functions to terminate cyclization of squalene at the bicyclic step (2017), ChemBioChem, 18, 1910-1913 .
Cloned(Commentary)
| Cloned (Comment) | Organism |
|---|---|
| recombinant expression of wild-type and mutant enzymes in Escherichia coli strain BL21(DE3) | Priestia megaterium |
Protein Variants
| Protein Variants | Comment | Organism |
|---|---|---|
| Y167A | site-directed mutagenesis, the enzyme mutant produces unnatural tricyclic triterpenol, deoxyarabidiol ((5E)-6,10-dimethyl-2-[(3R,3aR,5aS,9aS,9bR)-3a,6,6,9a-tetramethyldodecahydro-1H-cyclopenta[a]naphthalen-3-yl]undeca-5,9-dien-2-ol), product ratios compared to wild-type, overview | Priestia megaterium |
| Y167A/L596F | site-directed mutagenesis, the mutant catalyzes only the synthesis of 8alpha-hydroxypolypoda-13,17,21-triene and 3-deoxyarabidiol ((5E)-6,10-dimethyl-2-[(3R,3aR,5aS,9aS,9bR)-3a,6,6,9a-tetramethyldodecahydro-1H-cyclopenta[a]naphthalen-3-yl]undeca-5,9-dien-2-ol), no formation of baciterpenol from tetraprenyl-beta-curcumene or onoceranoxide and 14beta-hydroxyonocera-8(26)-ene from 8alpha-hydroxypolypoda-13,17,21-triene, product ratios compared to wild-type, overview | Priestia megaterium |
| Y167F | site-directed mutagenesis, the enzyme mutant forms small quantity of tricyclic compounds, product ratios compared to wild-type, overview | Priestia megaterium |
| Y167L | site-directed mutagenesis, the enzyme mutant forms small quantity of tricyclic compounds, product ratios compared to wild-type, overview | Priestia megaterium |
| Y167W | site-directed mutagenesis, the enzyme mutant forms small quantity of tricyclic compounds, product ratios compared to wild-type, overview | Priestia megaterium |
Natural Substrates/ Products (Substrates)
| Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| 8alpha-hydroxypolypoda-13,17,21-triene | Priestia megaterium | - |
onoceranoxide + 14beta-hydroxyonocera-8(26)-ene | - |
? |  |
| squalene | Priestia megaterium | - |
8alpha-hydroxypolypoda-13,17,21-triene | - |
? | |
| tetraprenyl-beta-curcumene + H2O | Priestia megaterium | - |
baciterpenol A | - |
? | |
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Priestia megaterium | - |
- |
- |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| 8alpha-hydroxypolypoda-13,17,21-triene | - |
Priestia megaterium | onoceranoxide + 14beta-hydroxyonocera-8(26)-ene | - |
? | |
| additional information | the enzyme is a bifunctional triterpene/sesquarterpene cyclase, catalytic reaction mechanism, overview. The wild-type enzyme forms 85.8% 8alpha-hydroxypolypoda-13,17,21-triene, 9.5% onoceranoxide, and 4.7% 14beta-hydroxyonocera-8(26)-ene from squalene, the ratios of mutants are altered. Compounds are identified by NMR spectroscopy | Priestia megaterium | ? | - |
? | |
| squalene | - |
Priestia megaterium | 8alpha-hydroxypolypoda-13,17,21-triene | - |
? | |
| squalene | catalytic mechanism, overview | Priestia megaterium | 8alpha-hydroxypolypoda-13,17,21-triene | - |
? | |
| squalene | reaction of all Y167 mutants, no activity with the wild-type enzyme, catalytic mechanism, overview. 3-Deoxyarabidiol, i.e. (5E)-6,10-dimethyl-2-[(3R,3aR,5aS,9aS,9bR)-3a,6,6,9a-tetramethyldodecahydro-1H-cyclopenta[a]naphthalen-3-yl]undeca-5,9-dien-2-ol, is directly synthesized from squalene in the first reaction | Priestia megaterium | 3-deoxyarabidiol + H2O | - |
? | |
| tetraprenyl-beta-curcumene + H2O | - |
Priestia megaterium | baciterpenol A | - |
? | |
| tetraprenyl-beta-curcumene + H2O | catalytic mechanism, overview | Priestia megaterium | baciterpenol A | - |
? | |
Synonyms
| Synonyms | Comment | Organism |
|---|---|---|
| BmTC | - |
Priestia megaterium |
General Information
| General Information | Comment | Organism |
|---|---|---|
| physiological function | onoceroids are a group of triterpenes biosynthesized from squalene or dioxidosqualene by cyclization from both termini. The bifunctional triterpene/sesquarterpene (TC) constructs a tetracyclic scaffold from tetraprenyl-beta-curcumene (C35) but a bicyclic scaffold from squalene (C30) in the first reaction. The enzyme also accepts the bicyclic intermediate as a substrate and generates tetracyclic and pentacyclic onoceroids in the second reaction, catalytic mechanism of an onoceroid synthase, overview. The bulk size at Y167 contributes to termination of the cyclization of squalene at the bicyclic step | Priestia megaterium |
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