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Arquitectura de la enzima: el dominio de unión de oxidianión activador para la orotidina 5'-monofosfato

Krisztina Spong¹, Tina L Amyes, John P Richard

¹Department of Chemistry, University at Buffalo, SUNY , Buffalo, New York 14260-3000, United States.

Journal of the American Chemical Society

|November 27, 2013

Resumen

La orotidina 5'-monofosfato descarboxilasa (OMPDC) utiliza oxidianiones tetraédricos para activar la catálisis de la enzima. Estos aniones estabilizan los estados de transición, mejorando la descarboxilación del orotato, un paso clave en la biosíntesis de la pirimidina.

Área de la Ciencia:

La bioquímica es la bioquímica.
Enzimología Enzimología.
Biología Estructural Biología Estructural

Sus antecedentes:

La orotidina 5 omino-monofosfato descarboxilasa (OMPDC) cataliza un paso crucial en la biosíntesis de la pirimidina.
Las reacciones de descarboxilación catalizadas por enzimas son esenciales en numerosas vías metabólicas.
Comprender los mecanismos enzimáticos, particularmente la estabilización del estado de transición, es clave para el desarrollo de fármacos.

Objetivo del estudio:

Investigar el papel de los oxidianiones tetraédricos en la activación del OMPDC.
Para aclarar el mecanismo por el cual OMPDC estabiliza los estados de transición durante la catálisis.
Para caracterizar las interacciones de unión de varios oxidianiones con OMPDC.

Principales métodos:

Los ensayos de cinética enzimática miden la actividad catalítica.
Determinación de las energías de unión intrínsecas de los oxidianiones.
Análisis estructural de las interacciones enzima-ligando (inferido).

Principales resultados:

La actividad de OMPDC es activada por oxidianiones tetraédricos, con diferentes afinidades de unión.
La unión más fuerte de los oxidianiones (por ejemplo, sulfito, fosfito) se correlaciona con una mayor activación catalítica.
Se propone un modelo en el que la unión al oxydianión induce cambios conformacionales que estabilizan el estado de transición en el dominio de unión al orotato.

Conclusiones:

Los oxidianiones tetraédricos juegan un papel crítico en la catálisis de OMPDC al estabilizar los estados de transición.
OMPDC posee dominios distintos para la unión al sustrato y la activación catalítica a través de oxidianiones.
Los hallazgos proporcionan información sobre los mecanismos enzimáticos y las posibles dianas para la intervención terapéutica.

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