EC Number   |
Substrates |
Organism |
Products |
Reversibility |
|---|
  4.2.3.157 | (2E,6E)-farnesyl diphosphate + H2O |
- |
Streptomyces malaysiensis |
(+)-isoafricanol + diphosphate |
- |
? |
| 4.2.3.157 | (2E,6E)-farnesyl diphosphate + H2O |
(+)-isoafricanol i.e. (1aS,4aR,5R,7aS,7bR)-3,3,5,7b-tetramethyldecahydro-4aH-cyclopropa[e]azulen-4a-ol |
Streptomyces rapamycinicus |
(+)-isoafricanol + diphosphate |
- |
? |
| 4.2.3.157 | (2E,6E)-farnesyl diphosphate + H2O |
(+)-isoafricanol i.e. (1aS,4aR,5R,7aS,7bR)-3,3,5,7b-tetramethyldecahydro-4aH-cyclopropa[e]azulen-4a-ol |
Streptomyces violaceusniger |
(+)-isoafricanol + diphosphate |
- |
? |
| 4.2.3.157 | (2E,6E)-farnesyl diphosphate + H2O |
the sesquiterpene alcohol (+)-isoafricanol is the main product (ca. 95%) plus traces of african-1-ene and african-2(6)-ene that are identified by GC/MS, (+)-isoafricanol i.e. (1aS,4aR,5R,7aS,7bR)-3,3,5,7b-tetramethyldecahydro-4aH-cyclopropa[e]azulen-4a-ol. Type I terpene cyclases ionise these achiral linear precursors by diphosphate abstraction, resulting in an allyl cation that undergoes multistep cyclisation cascades to a usually polycyclic terpene with several stereocentres. The cyclisation mechanism is extensively studied using isotopically labelled precursors. The enzyme follows a strict stereochemical course with respect to the fate of the geminal methyl groups C12 and C13, as observed for most terpene cyclases. Stereoselectively deuterated and 13C-labelled substrates reveal inversion of configuration at C1 during 1,11-cyclisation. Appropriate combinations of deuterium and 13C-labellings reveal two 1,2-hydride migrations including the stereochemical course for the second shift. No activity with geranyl diphosphate and geranylgeranyl diphosphate |
Streptomyces malaysiensis |
(+)-isoafricanol + diphosphate |
- |
? |
| 4.2.3.157 | (2E,6E)-farnesyl diphosphate + H2O |
(+)-isoafricanol i.e. (1aS,4aR,5R,7aS,7bR)-3,3,5,7b-tetramethyldecahydro-4aH-cyclopropa[e]azulen-4a-ol |
Streptomyces rapamycinicus NRRL 5491 |
(+)-isoafricanol + diphosphate |
- |
? |
| 4.2.3.157 | (2E,6E)-farnesyl diphosphate + H2O |
(+)-isoafricanol i.e. (1aS,4aR,5R,7aS,7bR)-3,3,5,7b-tetramethyldecahydro-4aH-cyclopropa[e]azulen-4a-ol |
Streptomyces violaceusniger Tü 4113 |
(+)-isoafricanol + diphosphate |
- |
? |
| 4.2.3.157 | (2E,6E)-farnesyl diphosphate + H2O |
- |
Streptomyces malaysiensis DSM 4137 |
(+)-isoafricanol + diphosphate |
- |
? |
| 4.2.3.157 | (2E,6E)-farnesyl diphosphate + H2O |
the sesquiterpene alcohol (+)-isoafricanol is the main product (ca. 95%) plus traces of african-1-ene and african-2(6)-ene that are identified by GC/MS, (+)-isoafricanol i.e. (1aS,4aR,5R,7aS,7bR)-3,3,5,7b-tetramethyldecahydro-4aH-cyclopropa[e]azulen-4a-ol. Type I terpene cyclases ionise these achiral linear precursors by diphosphate abstraction, resulting in an allyl cation that undergoes multistep cyclisation cascades to a usually polycyclic terpene with several stereocentres. The cyclisation mechanism is extensively studied using isotopically labelled precursors. The enzyme follows a strict stereochemical course with respect to the fate of the geminal methyl groups C12 and C13, as observed for most terpene cyclases. Stereoselectively deuterated and 13C-labelled substrates reveal inversion of configuration at C1 during 1,11-cyclisation. Appropriate combinations of deuterium and 13C-labellings reveal two 1,2-hydride migrations including the stereochemical course for the second shift. No activity with geranyl diphosphate and geranylgeranyl diphosphate |
Streptomyces malaysiensis DSM 4137 |
(+)-isoafricanol + diphosphate |
- |
? |
