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Bases estructurales del reconocimiento multidrogas por BmrR, un activador de transcripción de un transportador

E E Zheleznova¹, P N Markham, A A Neyfakh

¹Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland 97201-3098, USA.

|February 20, 1999

Resumen

La proteína BmrR de Bacillus subtilis se une a diversos fármacos desplegando una hélice alfa para exponer un bolsillo. Este mecanismo de unión, que implica interacciones hidrofóbicas y electrostáticas, es clave para la resistencia a múltiples fármacos.

Área de la Ciencia:

La bioquímica es la bioquímica.
Biología Molecular Biología Molecular
Biología Estructural Biología estructural.

Sus antecedentes:

Los transportadores de eflujo de drogas múltiples reconocen diversas toxinas.
El regulador de transcripción de Bacillus subtilis BmrR se une a las drogas catiónicas hidrofóbicas.
BmrR activa la expresión del transportador multidrogas Bmr tras la unión del fármaco.

Objetivo del estudio:

Para aclarar la base estructural de la unión de fármacos por BmrR.
Comprender el mecanismo de reconocimiento y selectividad de fármacos en BmrR.

Principales métodos:

Cristalografía de rayos X del dominio de unión multidrogas de BmrR.
Determinación de la estructura cristalina del complejo BmrR-tetrafenilfosfonio a una resolución de 2,7 y 2,8 A, respectivamente.

Principales resultados:

La unión de la droga induce el despliegue y la reubicación de una hélice alfa en BmrR.
Un bolsillo interno de unión de fármacos se expone al movimiento de la hélice.
La unión del tetrafenilfosfonio implica interacciones hidrofóbicas y electrostáticas, incluida una interacción clave con un residuo de glutamato enterrado para la selectividad catiónica.

Conclusiones:

BmrR emplea un cambio conformacional inducido por fármacos único para la unión.
El residuo de glutamato enterrado es crítico para la selectividad catiónica de BmrR.
Principios de unión similares pueden aplicarse a otras proteínas de unión multidrogas.

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