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Análisis estructural de la ligadura de iones metálicos a nucleótidos y ácidos nucleicos utilizando espectroscopia EPR
Charles G Hoogstraten1, Christopher V Grant, Thomas E Horton
1Department of Chemistry, University of California at Davis, One Shields Avenue, Davis, California 95616, USA.
Journal of the American Chemical Society
|January 31, 2002
Resumen
Las técnicas de resonancia paramagnética de electrones pulsados (EPR) mapean con precisión los sitios de unión de iones metálicos en los ácidos nucleicos. Este método revela detalles estructurales cruciales para la comprensión de los ribozimas y otros sistemas de ácido nucleico biológicamente importantes.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
- La biofísica es la biofísica.
Sus antecedentes:
- Los iones metálicos son esenciales para la estructura y función del ácido nucleico.
- Las moléculas catalíticas de ARN (ribozimas) a menudo requieren iones metálicos como cofactores.
Objetivo del estudio:
- Para analizar estructuralmente los iones de manganeso (Mn) unidos a nucleótidos y ácidos nucleicos utilizando EPR pulsado.
- Para demostrar la aplicabilidad de estas técnicas EPR a sistemas complejos de ARN.
Principales métodos:
- Se utilizaron técnicas de EPR pulsado: modulación de la envoltura de espín de electrones (ESEEM) y doble resonancia nuclear de espín de electrones y eco de electrones (2ESE-ENDOR).
- Etiquetado de isótopos empleado para una mejor caracterización estructural.
- Métodos aplicados a un modelo de mononucleótido (MnGMP), ARN de transferencia específico de fenilalanina y la ribozima cabeza de martillo.
Principales resultados:
- Se caracteriza por la ligadura de Mn (II) a nitrógenos con base de nucleótidos.
- Se identificaron interacciones en la esfera externa con grupos de fosfato.
- Distancias determinadas a etiquetas específicas de deuterio (2H) y niveles de hidratación de iones metálicos.
- Analizó con éxito la unión de iones metálicos en ARN de transferencia y una ribozima.
Conclusiones:
- El EPR pulsado con etiquetado de isótopos proporciona un análisis estructural completo de los iones metálicos unidos.
- Estos métodos son aplicables a sistemas de ácido nucleico grandes y estructurados como los ribozimas.
- Permite la caracterización estructural detallada de los iones metálicos en ácidos nucleicos biológicamente relevantes.
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