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El plegamiento de la proteína cotranslacional en el ribosoma monitoreado en tiempo real

Wolf Holtkamp¹, Goran Kokic¹, Marcus Jäger¹

¹Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.

Science (New York, N.Y.)

|November 28, 2015

Resumen

Las proteínas recién sintetizadas pueden plegarse en el ribosoma. Este estudio muestra que los pequeños dominios de proteínas se pliegan rápidamente durante la traducción, formando estructuras dentro del ribosoma antes de completarse.

Área de la Ciencia:

Biología molecular
La biofísica
El plegamiento de las proteínas

Sus antecedentes:

Los dominios de proteínas pueden alcanzar estructuras terciarias estables durante la síntesis ribosómica.
Comprender el plegamiento cotranslacional es crucial para la biogénesis de las proteínas.

Objetivo del estudio:

Para investigar el plegamiento en tiempo real de un pequeño dominio de proteína durante la traducción.
Para aclarar el mecanismo y la cinética del plegamiento cotranslacional.

Principales métodos:

Se utilizó un sistema de traducción in vitro reconstituido de alto rendimiento.
Observación en tiempo real del plegamiento del dominio de la proteína durante la síntesis.

Principales resultados:

El dominio N-terminal de E. coli HemK se somete a un plegamiento cotranslacional.
El plegamiento se inicia dentro del túnel de péptidos del ribosoma, formando un estado compacto y no nativo.
El reordenamiento a una estructura similar a la nativa ocurre inmediatamente después de la traducción, con la velocidad de las transiciones plegables limitada por la traducción.

Conclusiones:

El plegamiento cotranslacional es un proceso rápido y autónomo para dominios pequeños e intrínsecamente rápidos.
El confinamiento ribosomal influye en el paisaje conformacional durante el plegamiento temprano.
Este mecanismo puede ser común para los dominios de proteínas pequeñas.

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