Structural insights into thebaine synthase 2 catalysis.
Biochem Biophys Res Commun
; 529(2): 156-161, 2020 08 20.
Article
en En
| MEDLINE
| ID: mdl-32703404
ABSTRACT
Thebaine synthase 2 (THS2) that can transform (7S)-salutaridinol 7-O-acetate to thebaine catalyzes the final step of thebaine biosynthesis in Papaver somniferum. Here, the crystal structures of THS2 and its complex with thebaine are reported, revealing the interaction network in the substrate-binding pocket. Subsequent docking and QM/MM studies was performed to further explore the catalytic mechanism of THS2. Our results suggest that T105 may abstract the proton of C4-OH from the substrate under the assistance of H89. The resulting C4-O- phenolate anion then attacks the nearby C5, and triggers intramolecular SN2' syn displacement with the elimination of O-acetyl group. Moreover, the latter SN2' reaction is the rate-determining step of the whole enzymatic reaction with an overall energy barrier of 18.8 kcal/mol. These findings are of pivotal importance to understand the mechanism of action of thebaine biosynthesis, and would guide enzyme engineering to enhance the production of opiate alkaloids via metabolic engineering.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Papaver
/
Proteínas de Plantas
/
Tebaína
/
Ligasas
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Biochem Biophys Res Commun
Año:
2020
Tipo del documento:
Article