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Estructura de la proteína de penetración de la membrana del reovirus, Mu1, en un complejo con su protector, Sigma3
Susanne Liemann1, Kartik Chandran, Timothy S Baker
1Howard Hughes Medical Institute, Children's Hospital, Harvard Medical School, 320 Longwood Avenue, Boston, MA 02115, USA.
Cell
|February 8, 2002
Resumen
Los virus no envueltos como el reovirus usan la proteína Mu1 para penetrar en las células huésped. Un mecanismo de "interruptor de miristoil", que implica la escisión y reorganización de las proteínas, facilita esta entrada en la membrana.
Área de la Ciencia:
- Virología Virología.
- Biología Estructural Biología estructural.
- La bioquímica es la bioquímica.
Sus antecedentes:
- Los virus sin envoltura entran en las células a través de la penetración de la membrana, distinta de la fusión de la membrana.
- La proteína de la cápside externa del reovirus Mu1 es crucial para este proceso de penetración.
Objetivo del estudio:
- Para dilucidar el mecanismo molecular de la penetración de la membrana viral por el reovirus.
- Determinar la base estructural del papel de la proteína Mu1 en la entrada celular.
Principales métodos:
- Microscopía cryoelectrónica (cryo-EM) para visualizar el virión intacto.
- Análisis estructural del complejo heterohexamericano Mu1-Sigma3.
- Caracterización bioquímica de la escisión autolítica de Mu1.
Principales resultados:
- Se determinó la estructura del complejo Mu1(3) Sigma3(3) y se ajustó a la imagen cryo-EM del virión.
- Mu1 se somete a una escisión autolítica en Mu1N y Mu1C, con la disociación de Mu1N.
- Un cambio conformacional en el trímero Mu1 precede a la miristoilación y la inserción en la membrana.
Conclusiones:
- Se propone un mecanismo de "interruptor de miristoil" para la penetración viral.
- Este mecanismo implica la exposición al grupo miristoil, la escisión de Mu1N y la reorganización de Mu1C.
- La comprensión de este proceso es clave para los mecanismos de entrada viral.
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