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Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
Published on: March 9, 2012
Estimulación recíproca de la hidrólisis de GTP por dos GTPasas que interactúan directamente entre sí
1Department of Biochemistry and Biophysics, University of California Medical School, San Francisco 94143-0448, USA.
Science (New York, N.Y.)
|September 8, 1995
Resumen
Las proteínas de Escherichia coli Ffh y FtsY son proteínas diana de la membrana plasmática bacteriana. Un estudio muestra que su hidrólisis de GTP está recíprocamente acoplada, lo que sugiere que se regulan mutuamente en la orientación de proteínas.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Fisiología bacteriana fisiología bacteriana.
- El objetivo de la proteína de orientación.
Sus antecedentes:
- Las proteínas de unión al trifosfato de guanosina (GTP) de Escherichia coli Ffh y FtsY están implicadas en la proteína cotranslacional dirigida a la membrana plasmática bacteriana.
- El mecanismo preciso de su interacción e hidrólisis de nucleótidos sigue siendo objeto de investigación.
Objetivo del estudio:
- Para investigar la especificidad de los nucleótidos y la interacción de Ffh y FtsY en Escherichia coli.
- Para aclarar el mecanismo de hidrólisis de GTP en el sistema Ffh-FtsY.
Principales métodos:
- Se utilizó la mutagénesis dirigida al sitio para alterar la especificidad de nucleótidos de FtsY de GTP a trifosfato de xantosina (XTP).
- Los ensayos de hidrólisis de nucleótidos se realizaron utilizando ribonucleoproteína purificada Ffh-4.5S y proteínas FtsY de tipo silvestre o mutantes.
- Se evaluó la necesidad de nucleótidos específicos (GTP o XTP) en las reacciones de hidrólisis.
Principales resultados:
- El mutante FtsY, específico para XTP, estimuló la hidrólisis de GTP por la ribonucleoproteína Ffh-4.5S cuando estaba presente XTP.
- La ribonucleoproteína Ffh-4.5S y la GTP eran necesarias para la hidrólisis de XTP por el mutante FtsY.
- Estos resultados indican un acoplamiento recíproco en la hidrólisis del nucleótido trifosfato entre Ffh y FtsY.
Conclusiones:
- La hidrólisis del nucleótido trifosfato por Ffh y FtsY ocurre en reacciones recíprocamente acopladas.
- Es probable que Ffh y FtsY funcionen como proteínas reguladoras mutuas en la vía de orientación de proteínas.
- Esta regulación recíproca asegura un suministro eficiente y coordinado de proteínas a la membrana plasmática bacteriana.
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