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La ruptura de simetría y la amplificación quiral en las reacciones de ligadura prebiótica
Min Deng1, Jinhan Yu1, Donna G Blackmond2
1Department of Chemistry, Scripps Research, La Jolla, CA, USA.
Nature
|February 28, 2024
Resumen
La homoquiralidad biológica, esencial para la vida, surgió a través de una sorprendente preferencia por la ligadura heteroquiral en la formación de péptidos. Este proceso impulsa paradójicamente el enriquecimiento de las cadenas homoquirales, resolviendo un rompecabezas prebiótico clave.
Área de la Ciencia:
- El origen de los estudios de la vida
- Quiralidad en la bioquímica
- Química prebiótica
Sus antecedentes:
- La aparición de una sola quiralidad (homoquiralidad) en las moléculas biológicas es una característica fundamental de la vida.
- Las investigaciones anteriores se centraron en el enriquecimiento por enantio de los bloques de construcción de monómeros, pero el enriquecimiento parcial puede detener la polimerización.
- El "problema de la síntesis original" pone de relieve los desafíos en la formación de polímeros homoquirales a partir de monómeros parcialmente enriquecidos.
Objetivo del estudio:
- Para investigar una nueva ruta, prebióticamente plausible a los péptidos proteinogénicos.
- Para entender el mecanismo detrás de la aparición de péptidos homoquirales.
- Abordar el reto de formar polímeros homoquirales a partir de precursores potencialmente racémicos o parcialmente enriquecidos.
Principales métodos:
- Estudió una nueva vía de reacción prebiótica plausible para la síntesis de péptidos.
- Se ha investigado la ligadura heteroquiral (monómero L con monómero D) en la formación de péptidos.
- Se utilizaron datos experimentales y modelos cinéticos para apoyar los hallazgos.
- Efectos considerados de la solubilidad en la purificación y la amplificación quiral.
Principales resultados:
- La vía de reacción estudiada favorece inesperadamente la ligadura heteroquiral.
- Se ha demostrado que esta preferencia heteroquiral conduce paradójicamente a un enriquecimiento enantio de las cadenas de péptidos homoquiral.
- Se han observado rupturas de simetría, amplificación quiral y transferencia de quiralidad en mezclas de reacción complejas.
- Se ha demostrado que la solubilidad ayuda a una mayor purificación y amplificación quiral.
Conclusiones:
- La ligadura heteroquiral, que inicialmente parecía contraproducente, proporciona un mecanismo viable para la aparición prebiótica de péptidos homoquirales.
- Este mecanismo resuelve el "problema de la síntesis original" al permitir la amplificación quiral incluso a partir de mezclas no racémicas.
- Los hallazgos apoyan una vía plausible para el origen de los polímeros biológicos homoquirales, cruciales para la vida como la conocemos.
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