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Protein Modifications: Protein Kinases and Phosphatases

Protein Modifications: Protein Kinases and Phosphatases

Los cofactores B12 estabilizan directamente un interruptor de regulación del ARNm en el interruptor de regulación del

James E Johnson¹, Francis E Reyes, Jacob T Polaski

¹Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, Colorado 80309-0596, USA.

|October 16, 2012

Resumen

Este estudio revela cómo los riboswitches de vitamina B12 se unen a los derivados de B12, estabilizando las estructuras de ARN que controlan la expresión génica a través de nuevas interacciones.

Área de la Ciencia:

Biología Molecular Biología Molecular
Biología Estructural Biología estructural.
La bioquímica es la bioquímica.

Sus antecedentes:

Los ARN mensajeros (ARNm) utilizan riboswitches para unirse a pequeñas moléculas, regulando la expresión génica.
Los detalles mecánicos de cómo las estructuras de riboswitch se vinculan a la regulación génica no se comprenden completamente.

Objetivo del estudio:

Para aclarar los mecanismos estructurales por los cuales los riboswitches que se unen a la cobalamina (vitamina B12) reconocen diversos derivados de la vitamina B12.
Para detallar cómo estos riboswitches comunican señales dependientes de ligandos para regular la expresión de ARNm.

Principales métodos:

Determinación de la estructura cristalina de dos clases distintas de riboswitches de unión a la cobalamina.
Análisis de las interacciones ARN-ligando y reordenamientos estructurales.

Principales resultados:

Se identificó un núcleo común de unión a la cobalamina con distintas extensiones periféricas para reconocer diferentes derivados de la vitamina B12.
Reconocimiento de ligandos demostrado a través de la complementariedad de la forma con un mínimo de enlaces de hidrógeno.
Reveló un andamio compuesto de cobalamina-ARN que estabiliza una interacción de bucle de beso intramolecular crucial para la regulación génica.

Conclusiones:

Este trabajo proporciona la primera estructura cristalina que detalla la comunicación receptor-regulador en un riboswitch dependiente de ligandos.
Los hallazgos ofrecen información sobre la base molecular de la regulación génica por los riboswitches de cobalamina.

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