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Interacción de la urea con los aminoácidos: implicaciones para la desnaturalización de proteínas inducida por la urea
Martin C Stumpe1, Helmut Grubmüller
1Department of Theoretical and Computational Biophysics, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
Journal of the American Chemical Society
|December 1, 2007
Resumen
La desnaturalización de proteínas inducida por la urea es impulsada por interacciones hidrofóbicas, con enlaces de hidrógeno de la columna vertebral que proporcionan estabilidad adicional. Este estudio revela un mecanismo combinado para la urea.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- Física Química Física Química es la física de la química.
Sus antecedentes:
- El mecanismo molecular preciso de la desnaturalización de proteínas inducida por la urea sigue siendo incompletamente entendido.
- Dos teorías principales y contradictorias proponen las interacciones hidrofóbicas o polares como la fuerza motriz dominante.
Objetivo del estudio:
- Para dilucidar las interacciones entre la urea y los 20 aminoácidos.
- Para resolver el debate sobre el mecanismo dominante de la desnaturalización de proteínas inducida por la urea.
Principales métodos:
- Simulaciones completas de dinámica molecular de 22 tripeptídeos.
- Cálculo de las frecuencias de contacto atómico para determinar las preferencias de solvación.
Principales resultados:
- La mayoría de los aminoácidos, particularmente las cadenas laterales aromáticas y apolares y la columna vertebral de la proteína, prefieren los contactos de urea.
- Los aminoácidos cargados y polares muestran una ligera preferencia por el agua.
- Los enlaces de hidrógeno proteína-urea son más débiles que los enlaces de hidrógeno proteína-agua o agua-agua.
Conclusiones:
- Las interacciones hidrofóbicas son el principal motor de la desnaturalización de proteínas inducida por la urea.
- Los enlaces de hidrógeno de la columna vertebral con la urea contribuyen significativamente a estabilizar los sitios insatisfechos.
- Se propone un mecanismo unificado que combina las interacciones hidrofóbicas y polares.
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