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Conformador menor inherente de Bordetella Efector BteA Direcciones Despliegue mediado por Chaperón

Adi Yahalom¹, Hadassa Shaked¹, Sharon Ruthstein¹

¹Department of Chemistry, Bar Ilan University, Ramat Gan 52900, Israel.

Journal of the American Chemical Society

|June 24, 2022

Resumen

Bordetella pertussis chaperone BtcA despliega el efector BteA para la inyección en la célula huésped. Los estudios estructurales revelan que BtcA induce una conformación BteA más extendida, esencial para la función del sistema de secreción tipo 3.

Área de la Ciencia:

Microbiología
Biología estructural
Mecanismos moleculares

Sus antecedentes:

Bordetella pertussis utiliza un sistema de secreción de tipo 3 (T3SS) para administrar efectores citotóxicos como el BteA en las células huésped.
Se cree que el efector BteA es desplegado por su chaperón, BtcA, antes de la inyección a través de la aguja T3SS.

Objetivo del estudio:

Elucidar el mecanismo molecular por el cual la chaperona BtcA media el despliegue del efector BteA.
Para comprender los cambios conformacionales en BteA al unirse a BtcA.

Principales métodos:

Espectroscopia de resonancia magnética nuclear (RMN)
Espectroscopia de resonancia paramagnética de electrones (EPR)
Experimentos de dispersión por relajación por RMN

Principales resultados:

La unión de BtcA induce un cambio estructural global en BteA, lo que lleva a una conformación más extendida y parcialmente desplegada.
Las mediciones de EPR revelaron que el BteA libre existe en un equilibrio conformacional entre una forma estructurada y una especie menor y desplegada.
La dispersión de relajación de RMN identificó superficies específicas en BteA involucradas en el equilibrio conformacional y afectadas por la unión de BtcA.

Conclusiones:

Los hallazgos sugieren un mecanismo de selectividad conformacional en el que BtcA se une y estabiliza preferentemente a una conformación específica y menos estructurada de BteA.
Este mecanismo es crucial para el despliegue eficiente y la posterior inyección de BteA a través del T3SS.
El mecanismo identificado puede representar un paradigma común para las interacciones efector-chaperona en sistemas de secreción bacteriana relacionados.

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