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El residuo del sitio activo de APE1, Asn174, estabiliza el sitio activo de AP y es esencial para la catálisis
Kaitlin M DeHart1, Nicole M Hoitsma2, Spencer H Thompson1
1Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
The Journal of biological chemistry
|September 3, 2025
Resumen
El residuo N174 de la endonucleasa apurínica/apirimídica 1 (APE1) es crucial para la reparación del ADN. La mutación de N174 perjudica la escisión del sitio de AP, destacando su papel en la estabilización del ADN y el mantenimiento de un entorno de sitio activo óptimo.
Área de la Ciencia:
- Biología molecular
- La bioquímica
- La genética
Sus antecedentes:
- Los sitios apurínico/apirimídico (AP) son lesiones de ADN mutagénicas comunes.
- La vía de reparación por escisión de la base (BER, por sus siglas en inglés) se dirige a los sitios AP.
- La endonucleasa apurina/apirimidina 1 (APE1) inicia la reparación en el sitio de la AP a través de la actividad de la endonucleasa.
Objetivo del estudio:
- Investigar el papel funcional del residuo N174 del sitio activo de APE1.
- Determinar cómo las propiedades del N174 influyen en la escisión del sitio AP durante la reparación del ADN.
Principales métodos:
- Diseño racional de cuatro mutantes del APE1 (N174A, N174D, N174Q y N174K).
- Análisis cinético de la actividad de escisión en el sitio de la AP.
- Cristalografía de rayos X y simulaciones dinámicas moleculares de mutantes APE1.
Principales resultados:
- La escisión del sitio AP se vio afectada en los mutantes N174A, N174D y N174K.
- La falta de enlace de hidrógeno y la carga alterada en el residuo 174 contribuyeron a la escisión deteriorada.
- N174 estabiliza el ADN AP en el sitio activo de APE1 a través de enlaces de hidrógeno para una escisión eficiente.
Conclusiones:
- El residuo N174 es crítico para la función de la endonucleasa de APE1.
- El enlace de hidrógeno y el entorno electrostático óptimo proporcionado por N174 son esenciales para el procesamiento en el sitio de AP.
- El estudio proporciona información molecular sobre el mecanismo de APE1 en la reparación del ADN.
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