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Deterioro de la catálisis ácida por mutación de un residuo de bisagra de bucle de proteína en un mutante YopH
Tiago A S Brandão1, Howard Robinson, Sean J Johnson
1Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, USA.
Journal of the American Chemical Society
|January 15, 2009
Resumen
La mutación de un residuo de bisagra clave en la Yersinia proteína-tirosina fosfatasa YopH perjudica la catálisis. Los estudios estructurales revelan un bucle WPD medio cerrado, lo que explica la actividad enzimática reducida y la identificación de una nueva especie de divanadato.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
- Enzimología Enzimología.
Sus antecedentes:
- La Yersinia proteína-tirosina fosfatasa (YopH) es crucial para la virulencia bacteriana.
- El residuo de Trp354 conservado en YopH es un residuo de bisagra en el bucle WPD flexible, esencial para la catálisis.
- La mutación de Trp354 a Phe (W354F) reduce significativamente la actividad catalítica de YopH.
Objetivo del estudio:
- Para aclarar la base estructural para el deterioro catalítico causado por la mutación W354F en YopH.
- Para investigar el papel de la conformación del bucle WPD en la catálisis YopH.
- Para caracterizar la interacción de YopH con los oxyaniones.
Principales métodos:
- Determinación de la estructura cristalina de alta resolución de W354F YopH.
- Cristalografía de rayos X en ausencia y presencia de tungsteno y vanadato.
- Análisis de las interacciones enzima-inhibidor y las conformaciones del bucle.
Principales resultados:
- La unión del oxyanión al bucle P en W354F YopH es similar a la enzima nativa.
- El bucle WPD en W354F YopH adopta una conformación semicerrada con oxyaniones, a diferencia del estado completamente cerrado en el YopH nativo.
- Una estructura de 1,4 Å reveló una especie de divanadato cíclico sin precedentes vinculada a W354F YopH.
Conclusiones:
- El cierre defectuoso del bucle WPD en W354F YopH explica la reducción de la catálisis ácida general.
- Conocimientos estructurales sobre la función de YopH y el impacto de las mutaciones de los residuos de bisagra.
- Descubrimiento de una nueva especie de divanadato en una estructura cristalina de proteína.
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