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Efectos alostéricos de los cofactores de nucleótidos en Escherichia coli Rep helicasa-ADN que se une con el ADN
1Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110.
Science (New York, N.Y.)
|April 17, 1992
Resumen
La helicasa Rep de Escherichia coli se dimeriza al unirse al ADN, con cofactores de nucleótidos que influyen en la interacción del ADN. Este mecanismo es crucial para la replicación y el desenrollamiento del ADN.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
- Genética La genética.
Sus antecedentes:
- La helicasa Rep de Escherichia coli es esencial para desenrollar el ADN dúplex durante la replicación.
- La enzima funcional es un dímero que se forma al unirse al ADN, y cada protómero es capaz de unirse al ADN monocatenario o dúplex.
Objetivo del estudio:
- Para estudiar cuantitativamente la energética de la unión del ADN y la dimerización Rep inducida por el ADN.
- Para investigar la influencia de los cofactores de nucleótidos, adenosina difosfato (ADP) y adenosina trifosfato (ATP) análogo AMPP ((NH) P, en estos procesos.
Principales métodos:
- Análisis cuantitativo de la unión al ADN y la dimerización Rep.
- Uso de ADP y el análogo de ATP no hidrolizable AMPP ((NH) P como cofactores de nucleótidos.
Principales resultados:
- Los cofactores de nucleótidos ejercen efectos alostéricos significativos en la unión de la Rep helicasa al ADN.
- La unión de ADP promueve los dímeros Rep con ambos protómeros que se unen al ADN de una sola hebra.
- La unión de AMPP ((NH) P favorece a los dímeros Rep que se unen simultáneamente al ADN monocatenario y al ADN dúplex.
Conclusiones:
- Se propone un modelo rodante para el desenrollo del ADN por la helicasa dimérica Rep.
- La translocación de helicasa está acoplada a la unión de ATP, mientras que la hidrólisis de ATP impulsa el desenrollamiento de múltiples pares de bases de ADN por ciclo catalítico.
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