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La macrolactonización y la hidrólisis de la epothilona C son catalizadas por el dominio tioesterasa aislado de la
Christopher N Boddy1, Tanya L Schneider, Kinya Hotta
1Departments of Chemical Engineering, Stanford University, Stanford, California 94305-5025, USA.
Journal of the American Chemical Society
|March 20, 2003
Resumen
El dominio extirpado de la epotilona tioesterasa (TE) cataliza eficientemente la macrolactonización de la seco-epotilona C a la epotilona C. Este hallazgo aclara el papel de los dominios TE de la policetida sintasa (PKS) en la biosíntesis de la epotilona.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- Enzimología Enzimología.
Sus antecedentes:
- La biosíntesis de Epothilone C involucra un complejo multienzimático que incluye módulos de péptido sintetasa no ribosómica (NRPS) y policetida sintasa (PKS).
- El paso final es la cicloliberación catalizada por la tioesterasa (TE), pero la actividad de los dominios PKS TE aislados sigue sin estar clara.
Objetivo del estudio:
- Para investigar la actividad de macrolactonización de un dominio extirpado de epotilona tioesterasa (TE).
- Para determinar si los dominios PKS TE aislados pueden realizar el paso final de ciclización en la biosíntesis de epothilona C.
Principales métodos:
- La extirpación del dominio epothilone TE del sistema multienzimático.
- Evaluación de la eficiencia catalítica (kcat/KM) del dominio TE extirpado para la macrolactonización.
- Medición de la actividad de hidrólisis (kcat, KM) del dominio TE en sustratos de tioésteres relevantes.
Principales resultados:
- El dominio TE de epotilona extirpado catalizó eficientemente la macrolactonización de la seco-epotilona C a la epotilona C (kcat/KM = 0,41 +/- 0,03 min-1 mM-1).
- El dominio TE también exhibió actividad de hidrólisis tanto en los tioésteres de seco-epothilona C como en los de epothilona C, produciendo seco-epothilona C.
Conclusiones:
- Los dominios PKS TE aislados poseen actividad de macrolactonización, lo que confirma su papel en la biosíntesis de epothilona C.
- El dominio epothilone TE puede catalizar tanto la ciclización como la hidrólisis, destacando su versatilidad enzimática.
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