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La estructura de Nup58/45 sugiere un diámetro de poro nuclear flexible por el deslizamiento intermolecular
Ivo Melcák1, André Hoelz, Günter Blobel
1Laboratory of Cell Biology, Howard Hughes Medical Institute, Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
Science (New York, N.Y.)
|March 24, 2007
Resumen
El complejo de poros nucleares.
Área de la Ciencia:
- Biología celular Biología celular.
- Biología estructural Biología estructural.
- La bioquímica es la bioquímica.
Sus antecedentes:
- El complejo de poros nucleares (CPN) regula el transporte entre el núcleo y el citoplasma.
- Las nucleoporinas (Nups) forman el canal central del NPC, que tiene un diámetro flexible.
- Nup58 y Nup45 son componentes clave del canal de transporte central de la NPC.
Objetivo del estudio:
- Para aclarar la base estructural para la flexibilidad del canal de transporte central de la NPC.
- Para investigar la estructura cuaternaria de las regiones alfa-hélices de los mamíferos Nup58/45.
- Proponer un mecanismo para la regulación del diámetro en el NPC.
Principales métodos:
- Cristalografía de rayos X para determinar la estructura de las regiones alfa helicoidales de los mamíferos Nup58/45.
- Análisis de las interacciones proteína-proteína dentro de los tetrámeros Nup58/45.
- Comparación estructural de las diferentes conformaciones tetrámeras.
Principales resultados:
- Se identificaron tetrámeros distintos formados por dos dímeros antiparalelo de horquilla de pelo de Nup58/45.
- Caracterizó la interfaz hidrofóbica intradimérica y la asociación hidrofílica dímero-dímero.
- Se observó un desplazamiento lateral de los residuos hidrófilos, lo que sugiere un deslizamiento intermolecular de 11 angstroms.
Conclusiones:
- La estructura tetramérica identificada y el mecanismo de deslizamiento observado proporcionan información sobre la flexibilidad de NPC.
- Es probable que el deslizamiento circunferencial de las subunidades Nup58/45 contribuya al ajuste dinámico del diámetro del canal central del NPC.
- Este mecanismo estructural puede ser crucial para regular el transporte nucleocitoplasmático.
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