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Caracterización de la unión del péptido líder durante la catálisis por la nisina deshidratasa NisB
Lindsay M Repka1, Kenton J Hetrick1, See Hyun Chee1
1Department of Chemistry and Howard Hughes Medical Institute, University of Illinois, Urbana-Champaign , 600 South Mathews Avenue , Urbana , Illinois 61801 , United States.
Journal of the American Chemical Society
|March 15, 2018
Resumen
La enzima NisB deshidratasa modifica el péptido antibacteriano nisina. Los investigadores confirmaron que NisB utiliza un solo sitio de unión para su péptido líder durante la biosíntesis de nisina.
Área de la Ciencia:
- La bioquímica
- Biología molecular
- Enzimología
Sus antecedentes:
- La biosíntesis de nisina involucra a la deshidratasa NisB, que modifica el péptido precursor de NisA.
- NisA tiene un péptido núcleo C-terminal y un péptido líder N-terminal (LP) esencial para la deshidratación.
- El papel preciso de la LP en la deshidratación mediada por NisB sigue sin estar claro.
Objetivo del estudio:
- Para aclarar el mecanismo de interacción entre el péptido líder NisA (LP) y la deshidratasa NisB.
- Determinar si NisB utiliza un único sitio de unión tanto para la glutamilación como para la eliminación del glutamato.
Principales métodos:
- Diseñó un enlace disulfuro para vincular covalentemente el NisA LP con el NisB.
- Se evaluó la actividad de la deshidratasa del complejo ligado NisA-NisB.
- Investigó el orden de unión de NisA y tRNAGlu a NisB.
Principales resultados:
- El enlace de disulfuro diseñado ató con éxito a NisA LP a NisB.
- La enzima deshidrató completamente el NisA atado, confirmando un sitio de unión LP funcional.
- Estableció el orden de NisA y tRNA que se une a NisB que facilita la deshidratación.
Conclusiones:
- NisB emplea un solo sitio de unión para el NisA LP, que acomoda tanto la glutamilación como la eliminación del glutamato.
- Los hallazgos apoyan un mecanismo secuencial para la deshidratación de la nisina mediada por NisB.
- La comprensión de las interacciones LP-NisB proporciona información sobre los mecanismos de modificación después de la traducción.
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