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Estructura del virus del bosque de Semliki en complejo con su receptor VLDLR
Duanfang Cao1, Bingting Ma2, Ziyi Cao3
1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences (CAS), Beijing 100101, China.
Cell
|April 25, 2023
Resumen
El virus del bosque de Semliki (SFV) utiliza el receptor de lipoproteína de muy baja densidad (VLDLR) para la infección. El cryo-EM muestra VLDLR.
Área de la Ciencia:
- Virología
- Biología estructural
- La bioquímica
Sus antecedentes:
- El virus del bosque de Semliki (SFV) es un alfavirus.
- SFV utiliza el receptor de lipoproteína de muy baja densidad (VLDLR) para la entrada celular tanto en huéspedes vertebrados como en insectos vectores.
- Comprender la base molecular de esta interacción es crucial para desarrollar estrategias antivirales.
Objetivo del estudio:
- Para aclarar la estructura de alta resolución de SFV en complejo con VLDLR.
- Identificar los sitios específicos de unión y los mecanismos de interacción entre el SFV y el VLDLR.
- Investigar el papel de las repeticiones de LDLR de clase A (LA) de VLDLR en la unión de SFV.
Principales métodos:
- Para determinar la estructura del complejo SFV-VLDLR se empleó la criomicroscopia electrónica.
- Se realizó un análisis estructural para caracterizar la interfaz entre las proteínas virales y el VLDLR.
- Se llevaron a cabo estudios de afinidad vinculantes para evaluar la contribución de diferentes dominios de VLDLR.
Principales resultados:
- El VLDLR se une a múltiples sitios E1-DIII en la superficie del SFV a través de sus repeticiones de LDLR de clase A (LA) en la membrana distal.
- La repetición LA3 exhibe la mayor afinidad de unión al SFV.
- La interacción implica una pequeña interfaz (378 Å2) con las principales formaciones de puente de sal.
- Las repeticiones consecutivas de LA, no solo LA3, facilitan la unión sinérgica a través de ajustes rotacionales, lo que permite la interacción con múltiples sitios virales.
Conclusiones:
- El mecanismo de unión de VLDLR a SFV se caracteriza por interacciones sinérgicas mediadas por múltiples repeticiones de LA.
- Esta unión multivalente aumenta la afinidad y permite que los VLDLR de diversas especies se unan al SFV.
- Los hallazgos proporcionan información estructural sobre las interacciones entre el alfavirus y los receptores y las posibles dianas para la intervención terapéutica.
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