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Modelo de agarre de tijeras para el reconocimiento de ADN por una familia de proteínas de cremallera de leucina
C R Vinson1, P B Sigler, S L McKnight
1Howard Hughes Research Laboratories, Department of Embryology, Carnegie Institution of Washington, Baltimore, MD 21210.
Resumen
La proteína CCAAT-enhancer-binding protein (C/EBP) utiliza un modelo de unión al ADN de "adherencia de tijeras". Este modelo explica cómo C/EBP interactúa con las secuencias de ADN, involucrando su cremallera de leucina y su región básica.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Genética La genética.
- La bioquímica es la bioquímica.
Sus antecedentes:
- C/EBP es una proteína de unión al ADN específica de la secuencia que regula la expresión génica en las células de mamíferos.
- Su región de unión al ADN comparte similitudes con otras proteínas reguladoras como Fos y Jun.
- Se propone un motivo estructural bipartito, que incluye una cremallera de leucina y una región básica, para la unión del ADN.
Objetivo del estudio:
- Para evaluar los aminoácidos conservados en la región básica de C/EBP.
- Proponer un nuevo modelo para la unión de ADN C/EBP basado en el análisis de secuencias y conocimientos estructurales.
Principales métodos:
- Análisis de 11 secuencias de proteínas C/EBP deducidas.
- Evaluación de las propiedades de los aminoácidos conservados dentro de la región básica.
- Utilizando sondas químicas para estudiar los complejos de proteínas:ADN.
Principales resultados:
- Identificaron aminoácidos conservados en la región básica de C/EBP a una distancia invariante de la cremallera de leucina.
- Formuló un modelo de agarre de tijeras para la unión del ADN.
- Se demostró que la arquitectura del modelo es adecuada para interactuar con secuencias de ADN díadas simétricas.
Conclusiones:
- El modelo de agarre de tijeras proporciona una explicación estructural para el reconocimiento de ADN específico de C/EBP.
- Este modelo destaca la importancia de la cremallera de leucina y la interacción de la región básica con el ADN.
- Los datos experimentales apoyan el mecanismo propuesto de unión de C/EBP al ADN.
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