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Stereoquímica inesperada de la metilantionina en el SapT del Lantipéptido Morfogenético
Raymond Sarksian1, Julian D Hegemann2, Max A Simon3
1Department of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61822, United States.
Journal of the American Chemical Society
|March 30, 2022
Resumen
Los investigadores descubrieron una nueva estereoquímica en los residuos de metilantionina (MeLan) dentro de los lantipéptidos, una clase de péptidos sintetizados por ribosoma y modificados post-traducionalmente. Este hallazgo amplía nuestra comprensión de la estructura y la bioactividad de los antipeptídeos.
Área de la Ciencia:
- La bioquímica
- Biología molecular
- Microbiología
Sus antecedentes:
- Los latipeptidos son péptidos sintetizados ribosomalmente y modificados post-traducionalmente (RiPPs) que contienen enlaces cruzados de lationina (Lan) o metilantionina (MeLan).
- La estereoquímica de los residuos de (Me) Lan es crítica para la bioactividad del latipeptido.
- Los antipeptídeos caracterizados anteriormente exhiben solo 2S,3S o 2R,3R en sus residuos de MeLan.
Objetivo del estudio:
- Para reconstituir la vía de biosíntesis del latipeptido SapT de clase I en Escherichia coli.
- Caracterización de la estereoquímica de los residuos de MeLan en el SapT producido heterológicamente.
- Investigar la posible prevalencia y el origen de la nueva estereoquímica de MeLan en otros latipeptidos.
Principales métodos:
- Expresión heteróloga de la vía biosintética de SapT en E. coli.
- Síntesis de estándares químicos para el análisis estereoquímico.
- Análisis bioinformático de las enzimas biosintéticas de los latipeptidos.
- Mutagénesis dirigida al sitio para sondear mecanismos de reacción.
Principales resultados:
- Se ha reconstituido con éxito la vía biosintética de SapT en E. coli.
- Se identificaron tres residuos de MeLan en SapT con estereoquímica 2S,3R (d-allo-l-MeLan), un hallazgo novedoso para los antipeptídeos.
- El análisis bioinformático y la verificación experimental en Streptomyces coelicolor confirmaron la presencia de d-allo-l-MeLan en otros latipeptidos.
- Propuso y proporcionó evidencia de un mecanismo que explica el origen de esta estereocímica única.
Conclusiones:
- El descubrimiento de d-allo-l-MeLan en SapT amplía la diversidad estereocímica conocida de los lantipéptidos.
- Los datos bioinformáticos y experimentales sugieren que esta estereoquímica no es exclusiva de SapT y puede estar presente en otros latipeptidos.
- El estudio proporciona información sobre los mecanismos enzimáticos que rigen la formación de MeLan y la biosíntesis del latipeptídeo.
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