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Mecanismo molecular para la eliminación, una modificación post-traducional recién descubierta
Zhihong Ke1, Gregory K Smith, Yingkai Zhang
1Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA.
Journal of the American Chemical Society
|June 30, 2011
Resumen
Las enzimas bacterianas recién descubiertas llamadas liasas de fosfotreonina modifican las proteínas del huésped. Utilizan una nueva reacción de eliminación beta, denominada "eliminación", para eliminar los grupos de fosfato de los residuos de treonina.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- Enzimología Enzimología.
Sus antecedentes:
- Las modificaciones post-traducionales regulan la señalización de las células huésped.
- Las enzimas bacterianas pueden interferir con los procesos de las células huésped.
- La fosforilación de la treonina es una modificación reguladora clave.
Objetivo del estudio:
- Para dilucidar el mecanismo catalítico de las liasas de fosfotreonina bacteriana recién descubiertas.
- Para entender la modificación post-traducional de las proteínas de señalización de la célula huésped.
- Para investigar la nueva reacción de "eliminación".
Principales métodos:
- Estudios ab initio de Mecánica Cuántica/Mecánica Molecular (QM/MM) en el campo de la mecánica cuántica y la mecánica molecular.
- Análisis computacional de reacciones catalizadas por enzimas.
- Caracterización de las interacciones proteína-proteína.
Principales resultados:
- Las liasas bacterianas de fosfotreonina catalizan la eliminación irreversible de fosfato de la threonina a través de la eliminación β.
- El mecanismo de reacción sigue una vía similar a la de E1cB.
- Un agujero de oxyanión de la enzima, formado por Lys104 y Tyr158 de SpvC, estabiliza el carbanión intermedio.
Conclusiones:
- Las liasas bacterianas de fosfotreonina emplean un mecanismo único de "eliminación" para la desfosforilación.
- Este mecanismo implica una vía distinta similar a la de E1cB.
- El sitio activo de la enzima, específicamente el agujero de oxyanión, es crucial para estabilizar los intermediarios de reacción.
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