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Análisis conformacional cuantitativo de las interacciones electrostáticas funcionalmente importantes en la región

Vojtěch Kubáň, Pavel Srb¹, Hana Štégnerová

¹Institute of Organic Chemistry and Biochemistry , Czech Academy of Sciences , v.v.i., Flemingovo nám 2 , Prague 6 16610 , Czech Republic.

Journal of the American Chemical Society

|September 26, 2019

Resumen

Las proteínas intrínsecamente desordenadas (IDP) altamente cargadas se pliegan sobre sí mismas debido a las interacciones electrostáticas. Este plegamiento es crucial para la función, y las mutaciones lo interrumpen, afectando la transcripción y la aptitud celular.

Área de la Ciencia:

La bioquímica
Biología estructural
Biofísica molecular

Sus antecedentes:

Las proteínas intrínsecamente desordenadas (IDP) son cruciales para las funciones celulares.
Las interacciones electrostáticas influyen significativamente en la estructura y la función del IDP.
El estudio de IDPs altamente cargados presenta desafíos experimentales para la resolución atómica.

Objetivo del estudio:

Investigar el comportamiento conformacional de la subunidad δ altamente cargada de la ARN polimerasa de Bacillus subtilis.
Aclarar el papel de las interacciones electrostáticas en las propensiones estructurales de este IDP.
Determinar las consecuencias funcionales de las interacciones electrostáticas alteradas.

Principales métodos:

Mejoras de la relajación paramagnética por resonancia magnética nuclear (RMN)
Acoplamientos dipolares residuales
Cambios químicos
Diseminación en ángulo pequeño (SAS)
Mutagénesis dirigida al sitio

Principales resultados:

Se identificaron contactos transitorios entre regiones con carga positiva y negativa.
El segmento cargado negativamente se pliega de nuevo sobre la hebra cargada positivamente, compactando la proteína.
La mutación de la región positiva interrumpió los contactos de largo alcance, lo que llevó a una conformación extendida.
Las mutaciones afectaron significativamente la actividad de transcripción in vitro y la aptitud celular bacteriana in vivo.

Conclusiones:

Las interacciones electrostáticas impulsan la compactación de este IDP altamente cargado.
La interrupción de estas interacciones afecta la función de las proteínas y la aptitud del organismo.
La descripción precisa de la electrostática es vital para la comprensión de los mecanismos del PDI.

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