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Energéticas de las interacciones mediadas por el zinc en las vías alostéricas de las proteínas de los sensores
Dhruva K Chakravorty1, Trent M Parker, Alfredo J Guerra
1Department of Chemistry and Quantum Theory Project, University of Florida, Gainesville, Florida 32611-8435, United States.
Journal of the American Chemical Society
|December 11, 2012
Resumen
Los enlaces de hidrógeno mediados por zinc son cruciales para la unión del ADN en las proteínas sensibles a los metales. Las interacciones más fuertes en los sitios receptivos actúan como un interruptor, bloqueando la unión del ADN a la presencia de metal.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
- Biología computacional Biología computacional.
Sus antecedentes:
- Las proteínas detectoras de metales utilizan mecanismos alostéricos para la unión del operador de ADN.
- Los enlaces de hidrógeno interprotómero mediados por metales son clave para esta regulación alostérica.
Objetivo del estudio:
- Investigar la energética de las interacciones mediadas por zinc en las proteínas de las familias ArsR/SmtB y MarR.
- Proporcionar conocimientos estructurales sobre las formas de proteínas alostéricas no caracterizadas.
- Determinar el papel de los enlaces mediados por metales en la respuesta alostérica.
Principales métodos:
- Se emplearon métodos computacionales para estudiar las interacciones proteína-metal.
- Se realizó un análisis energético de los enlaces de hidrógeno mediados por zinc.
- Se llevaron a cabo simulaciones de apo-proteínas (sin metal).
Principales resultados:
- Las interacciones mediadas por zinc son significativamente más fuertes (∼8 kcal / mol) en los sitios alostéricos funcionales en comparación con los sitios que no responden.
- Estas fuertes interacciones superan el desorden en los sitios de enlace de hidrógeno.
- La interacción actúa como un interruptor, estabilizando una débil conformación de unión al ADN sobre la unión al metal.
Conclusiones:
- Los enlaces de hidrógeno de la segunda capa de coordinación mediada por metales tienen un papel funcional conservado en los sitios de respuesta alosterica.
- Este mecanismo es vital en los reguladores de transcripción sensibles al zinc.
- Los hallazgos ofrecen nuevos conocimientos estructurales sobre la alostería de proteínas.
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