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La constante dieléctrica aparente de las proteínas y su dependencia de la temperatura de los efectos de

Liaoyuan An¹, Yefei Wang, Ning Zhang

¹Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao, 266101, China.

Journal of the American Chemical Society

|September 6, 2014

Resumen

Este estudio introduce un nuevo protocolo de RMN para medir los cambios de campo eléctrico en las proteínas. El método cuantifica con precisión las perturbaciones de desplazamiento químico (CSP) y revela propiedades dieléctricas dependientes de la temperatura.

Área de la Ciencia:

La biofísica es la biofísica.
Biología Estructural Biología estructural.
Espectroscopia de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN)

Sus antecedentes:

Las mutaciones de las proteínas pueden alterar los campos eléctricos, afectando las interacciones moleculares.
Medir estos sutiles cambios de campo eléctrico de forma remota es un desafío.
La Resonancia Magnética Nuclear (RMN) es una herramienta poderosa para estudiar la estructura y la dinámica de las proteínas.

Objetivo del estudio:

Desarrollar y validar un protocolo de Resonancia Magnética Nuclear (RMN) para medir con precisión las perturbaciones de desplazamiento químico remoto (CSP).
Investigar la relación entre los cambios de campo eléctrico inducidos por mutaciones y las PSC.
Para determinar la constante dieléctrica aparente (εa) de las proteínas y su dependencia de la temperatura.

Principales métodos:

Utilizó un nuevo protocolo de RMN para medir (1) H ((N) CSPs en mutantes de la proteína GB3 (K19A y K19E).
Aplicó la ecuación de Buckingham para ajustar los CSP a los cambios en el campo eléctrico.
Realizó simulaciones de dinámica molecular en disolvente explícito.

Principales resultados:

Se logró una medición precisa de los CSP remotos y minuciosos causados por cambios en el campo eléctrico inducidos por mutaciones.
Se determinó una constante dieléctrica aparente (εa) de 8,6 ± 0,8 a 298 K para la proteína GB3.
Los CSP y los valores derivados de εa mostraron una fuerte dependencia de la temperatura, con un aumento de εa de 7.3 a 278 K a 10.5 a 313 K.
Las simulaciones de dinámica molecular destacaron la contribución significativa del agua disolvente a la εa.

Conclusiones:

El protocolo de RMN desarrollado permite la cuantificación precisa de las perturbaciones del campo eléctrico dentro de las proteínas.
El estudio proporciona información sobre las propiedades dieléctricas de las proteínas y la influencia de la temperatura.
El agua disolvente juega un papel crucial en el comportamiento dieléctrico observado de las proteínas.

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