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La estructura cristalina del dominio de ruptura y reunión de la ADN girasa
J H Morais Cabral1, A P Jackson, C V Smith
1Department of Biochemistry, University of Leicester, UK.
Nature
|August 28, 1997
Resumen
La ADN girasa bacteriana, una topoisomerasa tipo II, fue analizada estructuralmente. La estructura cristalina revela conocimientos sobre el superenrollamiento del ADN, los mecanismos enzimáticos y las interacciones de los antibióticos con quinolona.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- Biología Estructural Biología estructural.
Sus antecedentes:
- La ADN girasa es una topoisomerasa de ADN de tipo II crucial en bacterias.
- Regula el superenrolamiento del ADN a través de la rotura y la reunificación controladas del ADN.
- Este proceso es esencial para la replicación y transcripción del ADN.
Objetivo del estudio:
- Para determinar la estructura cristalina del dominio de "ruptura-reunión" de la ADN girasa.
- Para comparar su estructura con la topoisomerasa II de levadura para comprender los cambios conformacionales.
- Para dilucidar el mecanismo de la escisión del ADN y el sitio de interacción de los antibióticos quinolona.
Principales métodos:
- Cristalografía de rayos X con una resolución de 2,8 Å.
- Análisis estructural comparativo de la ADN girasa bacteriana y la topoisomerasa II de levadura.
- Análisis de los datos de mutación para la resistencia a las quinolonas.
Principales resultados:
- Se aclaró la estructura cristalina del dominio "ruptura-reunión" de la ADN girasa.
- Se identificó una nueva interfaz de dímeros y una superficie cóncava para la unión del ADN.
- La comparación estructural sugiere dos conformaciones clave en la vía enzimática.
- Se mapearon los residuos conservados alrededor de las tirosinas del sitio activo y los sitios de mutación de resistencia a la quinolona.
Conclusiones:
- El estudio proporciona una base estructural para la función de la ADN girasa en el superenrolamiento.
- Revela conocimientos mecanicistas sobre el paso y la liberación de segmentos de ADN.
- Los hallazgos iluminan cómo los antibióticos quinolona interactúan con la ADN girasa, informando el desarrollo de fármacos.
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