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Catálisis de dos iones metálicos en la adenilil ciclasa
J J Tesmer1, R K Sunahara, R A Johnson
1Howard Hughes Medical Institute, Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75235-9050, USA.
Science (New York, N.Y.)
|July 31, 1999
Resumen
La adenilil ciclasa (AC) utiliza un mecanismo de dos iones metálicos para la conversión de ATP, similar a las polimerasas de ADN. Los estudios estructurales revelan el sitio activo de AC, ofreciendo información sobre su función catalítica y sus orígenes evolutivos.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- Enzimología Enzimología.
Sus antecedentes:
- La adenilil ciclasa (AC) sintetiza el monofosfato cíclico de adenosina (cAMP), un segundo mensajero crucial que regula diversos procesos celulares.
- Si bien la estructura de la CA de los mamíferos es parcialmente conocida, su sitio activo y su mecanismo catalítico permanecen incompletamente definidos.
Objetivo del estudio:
- Para dilucidar la estructura del sitio activo y el mecanismo catalítico de la adenilil ciclasa.
- Para investigar el papel de los iones metálicos en la actividad enzimática AC.
Principales métodos:
- Se determinaron cuatro estructuras cristalinas de dominios catalíticos de CA.
- AC complejo con análogos de ATP y varios iones metálicos divalentes.
Principales resultados:
- Proporcionó un modelo detallado del complejo enzima-sustrato para AC.
- Demostró de manera concluyente la unión de dos iones metálicos dentro del sitio activo de AC.
- Se identificaron similitudes estructurales entre el sitio activo de AC y los de las ADN polimerasas.
Conclusiones:
- El mecanismo de dos iones metálicos es fundamental para la actividad catalítica de la CA.
- Las polimerasas de AC y ADN probablemente comparten un ancestro evolutivo común debido a las estructuras conservadas del sitio activo y los mecanismos catalíticos.
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