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La estructura cristalina de la recombinasa V(D) J RAG1-RAG2 es la siguiente:

Min-Sung Kim¹, Mikalai Lapkouski¹, Wei Yang¹

¹Laboratory of Molecular Biology, NIDDK, NIH, Bethesda, Maryland 20892, USA.

|February 25, 2015

Resumen

La estructura del complejo RAG1-RAG2 revela su forma en Y, crucial para la recombinación V(D) J en el sistema inmunológico. Este hallazgo explica las mutaciones en pacientes con inmunodeficiencia y sugiere vínculos evolutivos con las transposasas de ADN.

Área de la Ciencia:

Biología Estructural Biología estructural.
Inmunología Inmunología.
Biología Molecular Biología Molecular

Sus antecedentes:

La recombinación V(D) J genera diversos receptores inmunes (inmunoglobulinas y receptores de células T) a través de la unión de segmentos de ADN.
El complejo proteico RAG1-RAG2 inicia este proceso mediante la escisión del ADN específico del sitio.

Objetivo del estudio:

Para determinar la estructura cristalina del complejo RAG1-RAG2 del ratón.
Proporcionar información estructural sobre el mecanismo de la recombinación V(D) J y su relación con las mutaciones genéticas.

Principales métodos:

Se utilizó cristalografía de rayos X para determinar la estructura del complejo RAG1-RAG2 del ratón.
Análisis de la arquitectura del complejo y comparación con las enzimas conocidas de reordenamiento del ADN.

Principales resultados:

El complejo RAG1-RAG2 de 230 kDa forma un heterotetramero en forma de Y.
La estructura presenta un tallo RAG1 entrelazado y heterodímeros RAG1-RAG2 que forman los brazos, con el sitio activo ubicado en el centro.
La estructura racionaliza más de 60 mutaciones de pacientes y se alinea con los datos genéticos / bioquímicos.

Conclusiones:

La estructura determinada RAG1-RAG2 aclara la base molecular de la recombinación V(D) J.
Las similitudes estructurales con las transposasas sugieren mecanismos conservados para el reordenamiento del ADN a través de la evolución.
Esta información estructural ayuda a comprender las mutaciones relacionadas con la inmunodeficiencia.

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