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Introduction to Solid Supported Membrane Based Electrophysiology
Published on: May 11, 2013
Bases estructurales de la transducción de energía en el ciclo de transporte de MsbAA
Jinhui Dong1, Guangyong Yang, Hassane S McHaourab
1Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA.
Science (New York, N.Y.)
|May 14, 2005
Resumen
Este estudio revela cómo el transportador multidrogas MsbA utiliza ATP para mover sustratos, detallando los cambios conformacionales que impulsan el eflujo de fármacos en las células resistentes.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
- La biofísica molecular es la biofísica molecular.
Sus antecedentes:
- Los transportadores de casete de unión de ATP resistentes a múltiples fármacos (MDR ABC) son cruciales en el eflujo de drogas.
- Comprender su mecanismo de transporte es vital para combatir la resistencia a múltiples fármacos.
Objetivo del estudio:
- Para caracterizar el movimiento conformacional del transportador multidrogas MsbA.
- Aclarar el mecanismo de acoplamiento del gasto energético a la translocación del sustrato.
Principales métodos:
- El etiquetado de spin dirigido por el sitio.
- La espectroscopia de resonancia paramagnética de electrones (EPR, por sus siglas en inglés) es una espectroscopia de resonancia paramagnética de electrones.
- Ensayos funcionales basados en liposomas.
Principales resultados:
- El MsbA libre de ligandos exhibe conformaciones distintas de las estructuras cristalinas, con un embalaje más suelto y penetración de agua en el periplasma.
- La unión del trifosfato de adenosina (ATP) induce el cierre de la cámara de sustrato al citoplasma y aumenta la hidratación periplásmica.
- La hidrólisis de ATP acentúa los cambios en el entorno dieléctrico y la geometría de la cámara, impulsando el volcado y la salida del sustrato.
Conclusiones:
- El estudio establece la base dinámica estructural de la carrera de potencia en los transportadores MDR ABC.
- Estos hallazgos proporcionan información sobre el mecanismo de acceso alternativo de MsbA.
- Los cambios conformacionales identificados ofrecen una vía potencial para la salida del sustrato anfipático.
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