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Estructura del transportador ABC MsbA en complejo con ADP.vanadato y el lipopolisacárido
Christopher L Reyes1, Geoffrey Chang
1Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road CB105, La Jolla, CA 92137, USA.
Science (New York, N.Y.)
|May 14, 2005
Resumen
El estudio revela la estructura de MsbA, un transportador de ABC, proporcionando información sobre la resistencia a múltiples fármacos. Propone un mecanismo de "flip-flop" de lípidos para el transporte de sustratos a través de las membranas celulares.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
- Biología Molecular Biología Molecular
Sus antecedentes:
- Los transportadores de adenosina trifosfato (ATP) en la cinta de unión (ABC) son proteínas de membrana cruciales involucradas en el eflujo del sustrato.
- Estos transportadores, a través de la unión de ATP y la hidrólisis, pueden conferir resistencia a múltiples fármacos.
- MsbA es un transportador ABC clave implicado en los procesos celulares y la resistencia.
Objetivo del estudio:
- Para aclarar el mecanismo estructural de la función MsbA.
- Comprender cómo MsbA facilita el transporte del sustrato y confiere resistencia a múltiples fármacos.
- Proponer un modelo para la comunicación del dominio de unión de nucleótidos con el dominio transmembrana.
Principales métodos:
- Se empleó cristalografía de rayos X para determinar la estructura de MsbA.
- La estructura fue determinada en complejo con magnesio, adenosina difosfato y vanadato inorgánico (Mg.ADP.Vi).
- La estructura también se determinó en complejo con lipopolisacárido de quimiotipo bruto (Ra LPS).
Principales resultados:
- La estructura determinada apoya un modelo de par de torsión de cuerpo rígido en los dominios transmembrana durante la hidrólisis de ATP.
- Los hallazgos sugieren una vía de comunicación entre el dominio de unión de nucleótidos y el dominio transmembrana.
- Se propone un nuevo mecanismo de "flip-flop" de lípidos para la translocación del sustrato.
Conclusiones:
- La estructura MsbA proporciona una base mecanicista para comprender la función del transportador ABC en el eflujo del sustrato.
- El mecanismo de "flip-flop" de lípidos propuesto ofrece nuevos conocimientos sobre el transporte de la membrana.
- Esta investigación contribuye a la comprensión de los mecanismos de resistencia a múltiples fármacos.
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