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piggyBac Transposon System Modification of Primary Human T Cells
Published on: November 5, 2012
Un interruptor conformacional del azúcar ribosa en el tracto polipurino LTR-retrotransposón Ty3 que contiene ARN/ADN
Hye Young Yi-Brunozzi1, Danielle M Brabazon, Daniela Lener
1HIV Drug Resistance Program, NCI-Frederick, Frederick, Maryland 21702, USA.
Journal of the American Chemical Society
|November 25, 2005
Resumen
El análisis estructural de un tracto polipurino (PPT) revela un interruptor de azúcar inesperado en la cadena de ARN. Este cambio de conformación afecta la fidelidad de la enzima RNasa H durante el procesamiento de la retrotransposón.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- La biofísica es la biofísica.
- Biología Estructural Biología estructural.
Sus antecedentes:
- Los tractos polipurinos (PPT) son elementos híbridos de ARN/ADN cruciales en la replicación del retrotransposón.
- El reconocimiento y procesamiento específico de PPTs por enzimas como la RNasa H son esenciales para la fidelidad de la replicación viral.
Objetivo del estudio:
- Investigar las bases estructurales del reconocimiento y procesamiento del tracto polipurino (PPT).
- Para aclarar el papel de la estructura híbrida de ARN / ADN en la fidelidad de la escisión mediada por enzimas.
Principales métodos:
- Se empleó la espectroscopia de Resonancia Magnética Nuclear (RMN) de Solución.
- Se utilizaron experimentos homonucleares NOESY y DQF-COSY para analizar la estructura híbrida de ARN/ADN.
Principales resultados:
- Se estudió un modelo híbrido de 20 bp de ARN / ADN que contiene el PPT de retrotransposón Ty3 de Saccharomyces cerevisiae.
- El híbrido adoptó una geometría helicoidal con forma de A.
- Se observó un inesperado cambio de azúcar de tipo A a tipo B para la ribosa en la posición +1 en la hebra de ARN.
Conclusiones:
- El interruptor de azúcar cambia significativamente la trayectoria de la columna vertebral del ARN y la presentación de los grupos funcionales.
- Esta distorsión conformacional cerca del sitio de la escisión sugiere un mecanismo para la fidelidad de RNase H.
- La conformación de hélice alterada de un par de bases aguas arriba del enlace de escisión puede contribuir a la especificidad de la enzima.
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