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Diversidad de secuencias en el marco del péptido lasso: descubrimiento de variantes funcionales de microcina J25 con
1Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA.
Journal of the American Chemical Society
|March 12, 2011
Resumen
Los investigadores diseñaron Microcin J25 (MccJ25), un péptido antimicrobiano, para mejorar la función. La mutación de la región de la cola produjo variantes potentes, mientras que las mutaciones en el anillo deterioraron la actividad, revelando información sobre las relaciones estructura-función del péptido lasso.
Área de la Ciencia:
- Microbiología Microbiología.
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
Sus antecedentes:
- Microcin J25 (MccJ25) es un péptido antimicrobiano sintetizado por ribosoma con una estructura de lazo única.
- Su producción en Escherichia coli implica un grupo de cuatro genes (mcjA, mcjB, mcjC, mcjD) para la síntesis de péptidos, la maduración y la inmunidad.
- El gen mcjD codifica una bomba de exportación que proporciona inmunidad al MccJ25.
Objetivo del estudio:
- Desarrollar un sistema de control independiente de la producción y exportación/inmunidad de MccJ25.
- Para examinar las bibliotecas de mutagénesis de MccJ25 para identificar variantes funcionales.
- Para investigar la relación estructura-función del péptido lasso MccJ25.
Principales métodos:
- Desarrolló un sistema de expresión génica ortogonal para mcjA y mcjD en E. coli.
- Bibliotecas de mutagenesis de saturación seleccionadas que se dirigen a las regiones de anillo y cola de MccJ25.
- Actividad antimicrobiana evaluada de las variantes de MccJ25 contra cepas sensibles como E. coli y Salmonella enterica.
Principales resultados:
- Descubrió casi 100 nuevas variantes de MccJ25 que conservan la función antimicrobiana.
- Se identificó que las mutaciones en la región de la cola son generalmente bien toleradas, mientras que las mutaciones en el anillo perjudican significativamente la función.
- Se ha demostrado que las variantes de anillo afectadas no se transportan al citoplasma.
- Se encontraron variantes de MccJ25 con hasta 5 veces mayor potencia contra cepas sensibles.
Conclusiones:
- El estudio proporciona un sistema para diseccionar la producción e inmunidad de MccJ25.
- Los estudios de mutagenesis revelan el papel crítico de la estructura de anillo MccJ25 para la actividad antimicrobiana y la absorción celular.
- Las modificaciones de la región de la cola pueden mejorar la potencia de MccJ25, destacando la tolerancia del pliegue péptido de lasso a la diversidad de secuencias.
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