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Examining the Conformational Dynamics of Membrane Proteins in situ with Site-directed Fluorescence Labeling
Published on: May 29, 2011
Los cambios de conformación en una enzima ultrarrápida impulsada por la luz determinan la actividad catalítica.
Olga A Sytina1, Derren J Heyes, C Neil Hunter
1Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
Nature
|December 19, 2008
Resumen
Los cambios en la conformación de la enzima, cruciales para el poder catalítico, se dilucidaron utilizando NADPH:protoclorophillide oxidoreductasa. La excitación láser indujo conformaciones favorables del sitio activo, permitiendo transferencias eficientes de hidruro y protón para la catálisis.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Enzimología Enzimología.
- Biología Estructural Biología estructural.
Sus antecedentes:
- El poder catalítico de las enzimas es una importante cuestión biológica.
- Las enzimas modulan las velocidades de reacción a través de movimientos de proteínas, pero es difícil distinguir esto de la catálisis.
Objetivo del estudio:
- Investigar el papel de los cambios conformacionales en la catálisis enzimática.
- Para utilizar NADPH:protoclorofilurido (Pchlide) oxidorreductaza como un sistema modelo para una reacción impulsada por la luz.
Principales métodos:
- Estudió la enzima biosintética de la clorofila NADPH:protoclorofilurido (Pchlide) oxidorreducta.asa.
- Se utilizó la excitación por pulso láser del complejo enzima-sustrato.
- Cambios espectrales analizados utilizando espectroscopia de infrarrojo medio después de la absorción de un solo fotón.
Principales resultados:
- La excitación láser indujo una conformación del sitio activo de la enzima más favorable.
- Este cambio de conformación permitió reacciones de hidruro acoplado y transferencia de protones.
- Los cambios espectrales observados indicaron cambios significativos en la conformación y dinámica de las enzimas.
Conclusiones:
- Los cambios de conformación son críticos para la eficiencia catalítica de las enzimas.
- La flexibilidad y la dinámica de las enzimas son esenciales para su funcionamiento.
- Los cambios conformacionales inducidos por la luz pueden cambiar las enzimas a un estado altamente activo.
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