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Movimientos intrínsecos a lo largo de una trayectoria de reacción enzimática
Katherine A Henzler-Wildman1, Vu Thai, Ming Lei
1Department of Biochemistry and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02454, USA.
Nature
|November 21, 2007
Resumen
Las enzimas utilizan cambios conformacionales específicos para lograr la catálisis. La dinámica de la enzima adenilato quinasa revela vías preferidas hacia un estado catalíticamente activo, que guía la función de la enzima.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
- Enzimología Enzimología.
Sus antecedentes:
- Las enzimas aceleran las reacciones bioquímicas a través de la unión al sustrato y los cambios conformacionales.
- La comprensión de cómo las enzimas alcanzan su estado catalíticamente competente es crucial para el esclarecimiento del mecanismo enzimático.
- La adenilato quinasa es una enzima modelo para el estudio de la dinámica conformacional y la catálisis.
Objetivo del estudio:
- Para investigar los subestados conformacionales y las vías dinámicas de la adenilato quinasa libre de ligandos.
- Proporcionar evidencia cristalográfica y computacional de los cambios conformacionales de las enzimas.
- Comprender cómo la estructura de la enzima facilita una catálisis eficiente.
Principales métodos:
- Cristalografía de rayos X para capturar subestados conformacionales.
- Simulaciones de dinámica molecular para modelar la dinámica de las enzimas.
- Resonancia magnética nuclear (RMN) y transferencia de energía de resonancia de fluorescencia de una sola molécula (smFRET) para estudiar escalas de tiempo del movimiento.
Principales resultados:
- Evidencia cristalográfica para los estados conformacionales en la adenilato quinasa libre de ligandos.
- Las simulaciones de dinámica molecular muestran conformaciones parcialmente cerradas muestreadas en una escala de tiempo de nanosegundos.
- La RMN y el smFRET revelan un raro muestreo del estado totalmente cerrado y catalíticamente competente en la escala de tiempo de microsegundos a milisegundos.
Conclusiones:
- La adenilato quinasa libre de sustrato exhibe movimientos conformacionales dirigidos hacia un estado catalíticamente competente.
- Estas vías preferidas son inherentes al pliegue de la enzima y pueden ser un principio general en la catálisis enzimática.
- La estructura de la enzima dicta las vías dinámicas, optimizando la enzima para las reacciones químicas.
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