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Proteína S-Glicomodificación a través de un mecanismo de eliminación-adición
Journal of the American Chemical Society
|April 28, 2020
Resumen
Los investigadores descubrieron una nueva reacción llamada S-glicomodificación donde los azúcares se unen a las proteínas. Este descubrimiento conduce a un método refinado para el etiquetado metabólico del glicano (MGL) en las células.
Área de la Ciencia:
- Biología Química
- Glicobiología
- Química orgánica
Sus antecedentes:
- Los monosacáridos no naturales per-O-acetilados son cruciales para el etiquetado del glicano metabólico (MGL).
- Una reacción no específica recientemente descubierta, denominada "glicosilación S", ocurre entre estos azúcares y las proteínas cisteínas.
- El mecanismo subyacente a esta reacción de glicosilación S sigue siendo en gran medida desconocido.
Objetivo del estudio:
- Para aclarar el mecanismo de reacción detallado de la S-glicomodificación.
- Comprender la formación de S-glucosilación artificial entre los azúcares y las proteínas cisteínas.
- Desarrollar monosacáridos no naturales mejorados para una LGM más eficaz.
Principales métodos:
- Investigación mecanicista de la reacción de S-glicomodificación.
- Análisis de las reacciones promovidas por bases de los monosacáridos per-O-acetilados.
- Identificación de los productos intermedios de la reacción.
Principales resultados:
- La glicosilación S es una glicosilación atípica denominada S-glicomodificación.
- Los monosacáridos per-O-acetilados se someten a una eliminación β-promovida por la base para formar aldehídos α,β-insaturados.
- Estos aldehídos reaccionan con los residuos de cisteína a través de la adición de Michael, dando azúcares 3-tiolados en forma hemiacetal.
Conclusiones:
- El mecanismo de S-glicomodificación incluye la eliminación-adición, no la glicosilación típica.
- Esta comprensión permite el desarrollo de monosacáridos no naturales mejorados.
- Se propone la 1,6-di-propionil-N-azidoacetilgalactosamina (1,6-Pr2GalNAz) como un reactivo mejorado de la MGL.
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