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La estructura de resonancia magnética nuclear de la solución de la diacilglicerol quinasa integrada en la membrana
Wade D Van Horn1, Hak-Jun Kim, Charles D Ellis
1Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA.
Science (New York, N.Y.)
|June 27, 2009
Resumen
Escherichia coli diacilglicerol quinasa (DAGK), una enzima de membrana integral, tiene una inusual estructura de homotrimero con intercambio de dominio. Su portico del sitio activo determina la especificidad del sustrato lipídico y está relacionado con el plegamiento de la enzima.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
- Enzimología Enzimología.
Sus antecedentes:
- La diacilglicerol quinasa de Escherichia coli (DAGK) es una enzima única de membrana integral.
- Pertenece a una familia distinta de fosfotransferasas, sin relación con otras enzimas conocidas.
- Comprender su estructura es crucial para aclarar su función y mecanismo.
Objetivo del estudio:
- Para determinar la estructura tridimensional de la Escherichia coli diacilglicerol quinasa (DAGK) homotrimer. para determinar la estructura tridimensional del Escherichia coli diacilglicerol quinasa (DAGK) homotrimer. para determinar la estructura tridimensional de la Escherichia coli diacilglicerol quinasa (DAGK) homotrimer. para determinar la estructura tridimensional de la Escherichia coli diacilglicerol quinasa (DAGK) homotrimer. para determinar la estructura tridimensional de la Escherichia coli diacilglicerol quinasa (DAGK) homotrimer. para determinar la estructura tridimensional de la Escherichia coli diacilglicerol quinasa (DAGK) homotrimer.
- Para investigar la base estructural de la especificidad del sustrato lipídico de DAGK.
- Explorar la relación entre el plegamiento enzimático y la actividad catalítica.
Principales métodos:
- Se empleó la espectroscopia de resonancia magnética nuclear (RMN) de solución.
- Se resolvió la estructura tridimensional del homotrimero DAGK.
- La mutagénesis dirigida al sitio se utilizó para estudiar el plegamiento y la catálisis.
Principales resultados:
- El homotrimer DAGK exhibe una arquitectura inusual de intercambio de dominios.
- Se identificó una estructura de sitio activo similar a un "pórtico", con la "cornisa" que dicta la especificidad del sustrato lipídico.
- El sitio activo se encuentra cerca de la interfaz agua-membrana.
- Se encontraron mutaciones que causan plegamiento incorrecto en o cerca del sitio activo.
Conclusiones:
- La estructura de intercambio de dominio de DAGK es una característica clave de su mecanismo funcional.
- La estructura de "pórtico" del sitio activo es crítica tanto para la especificidad del sustrato como para el plegamiento de la enzima.
- Hay una superposición significativa entre las regiones responsables del plegamiento de proteínas y la actividad catalítica en DAGK.
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