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Identificación espectroscópica de los diferentes tipos de centros de cobre generados en las proteínas sintéticas de
Robert Schnepf1, Wolfgang Haehnel, Karl Wieghardt
1Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim a. d. Ruhr, Germany. rs@complex-biosystems.com
Journal of the American Chemical Society
|November 4, 2004
Resumen
Los investigadores crearon proteínas sintéticas estables que se unen al cobre utilizando un enfoque combinatorio racional. Estas proteínas modificadas exhiben una mayor estabilidad y especificidad, lo que permite una caracterización detallada de diversos sitios de unión al cobre.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Ingeniería de proteínas Ingeniería de proteínas.
- Química bioorgánica Química bioorgánica.
Sus antecedentes:
- Las proteínas sintéticas ensambladas en plantilla ofrecen una plataforma para el diseño de metaloproteínas.
- El control de la coordinación de iones metálicos dentro de los andamios de proteínas es crucial para la función.
- Los diseños anteriores eran prometedores, pero requerían una mayor estabilidad y especificidad.
Objetivo del estudio:
- Para diseñar proteínas sintéticas estables de cuatro hélices de haces de proteínas con sitios específicos de unión de cobre.
- Investigar cómo las variaciones de la secuencia influyen en la estabilidad de las metaloproteínas y en las propiedades del centro de cobre.
- Para caracterizar las propiedades estructurales y electrónicas de los sitios de unión de cobre de ingeniería.
Principales métodos:
- Enfoques combinados de diseño de proteínas racionales y combinatorias.
- Síntesis y caracterización de 180 péptidos de haces de cuatro hélices distintos.
- Análisis espectroscópico que incluye UV-Vis, EPR y CD para estudiar la coordinación del cobre.
Principales resultados:
- Aproximadamente el 90% de las proteínas sintetizadas se unen con éxito al cobre con alta especificidad.
- La estabilidad de las metaloproteínas aumentó hasta dos órdenes de magnitud.
- Se identificaron tres tipos distintos de sitios de unión del cobre (tipo I, tipo II y una imitación de Cu (A)) controlados por factores estéricos.
Conclusiones:
- Los sitios de unión de cobre estructuralmente diversos y estables pueden ser diseñados con éxito en proteínas de haz de cuatro hélices.
- Las influencias estéricas cerca del conjunto de ligandos His2Cys son críticas para dictar la geometría de coordinación.
- Este trabajo proporciona una base para el diseño de nuevas metaloproteínas con funciones a medida.
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