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From Constructs to Crystals – Towards Structure Determination of β-barrel Outer Membrane Proteins
Published on: July 4, 2016
Estructuras de rayos X de LeuT en estados libres de sustrato hacia afuera abierto y apo hacia adentro abierto
Harini Krishnamurthy1, Eric Gouaux
1Vollum Institute, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, USA.
Nature
|January 11, 2012
Resumen
Las ideas estructurales sobre los simportores de sodio del neurotransmisor revelan cómo la unión del sustrato cierra el transportador. Nuevas estructuras cristalinas aclaran los estados de apertura hacia afuera y hacia adentro, aclarando los mecanismos de transporte de iones y sustratos.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
- La neurociencia es la neurociencia.
Sus antecedentes:
- Los neurotransmisores simportadores de sodio (NSS) son cruciales para la transmisión sináptica, limpiando los neurotransmisores como la serotonina y la dopamina.
- Las estructuras cristalinas anteriores del homólogo NSS LeuT proporcionaron información, pero dejaron sin respuesta preguntas mecánicas clave.
Objetivo del estudio:
- Para determinar las estructuras cristalinas de LeuT en estados abiertos hacia afuera e interiores.
- Para aclarar los cambios conformacionales subyacentes al transporte de sustrato y la translocación iónica en NSS.
Principales métodos:
- Cristalografía de rayos X de mutantes LeuT complejos con fragmentos de anticuerpos específicos de la conformación.
- Análisis de los cambios estructurales en los dominios transmembranares y los bucles extracelulares.
Principales resultados:
- Las estructuras cristalinas revelan LeuT en conformaciones abiertas hacia fuera y abiertas hacia adentro.
- La unión al sustrato cierra la puerta extracelular a través de cambios conformacionales locales.
- El estado de apertura hacia adentro implica reorientaciones de dominio a gran escala, cerrando el vestíbulo extracelular y abriendo uno intracelular.
Conclusiones:
- Estas estructuras proporcionan un marco para comprender el mecanismo de NSS y la modulación por drogas.
- Los hallazgos aclaran cómo los iones y sustratos se liberan en el citoplasma.
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