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El etiquetado selectivo de isótopos y el LC-Photo-CIDNP permiten la espectroscopia de RMN a baja concentración

Hanming Yang¹, Siyu Li¹, Clayton A Mickles¹

¹Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States.

Journal of the American Chemical Society

|June 14, 2022

Resumen

La sensibilidad de la espectroscopia de resonancia magnética nuclear (RMN) se mejora mediante la polarización nuclear dinámica inducida fotoquímicamente de baja concentración (LC-foto-CIDNP). Los isotopólogos de triptófano diluidos en espín aumentan significativamente la hiperpolarización LC-foto-CIDNP para la detección de muestras diluidas.

Área de la Ciencia:

Biofísica y Química
Espectroscopia
Biología estructural

Sus antecedentes:

La espectroscopia de resonancia magnética nuclear (RMN) es crucial para la estructura y la dinámica molecular.
La sensibilidad limitada limita la aplicación de la RMN con muestras diluidas.
La polarización nuclear dinámica inducida fotoquímicamente de baja concentración (LC-foto-CIDNP) mejora la sensibilidad a la RMN para los aminoácidos aromáticos.

Objetivo del estudio:

Investigar el efecto de la proximidad de núcleos NMR-inactivos en la hiperpolarización LC-foto-CIDNP.
Desarrollar una mayor sensibilidad a la RMN para detectar moléculas biológicas muy diluidas.
Demostrar la utilidad de los isotopólogos diluidos en espín para aplicaciones avanzadas de RMN.

Principales métodos:

Predicción teórica de la hiperpolarización mejorada en sistemas diluidos de espín.
Utilizando un isotopólogo de triptófano diluido con espín (Trp-α-13C-β,β,2,4,5,6,7-d7).
Validación experimental de la sensibilidad aumentada a la RMN utilizando el LC-foto-CIDNP.

Principales resultados:

La ausencia de núcleos activos por RMN cerca de los sitios objetivo aumenta significativamente la hiperpolarización LC-foto-CIDNP.
Un poco. Se logró una mejora de la sensibilidad de 4 veces con el isotopólogo de Trp diluido en espín.
Detección de concentraciones de 20 nM (límite de 3 ng) en cuestión de segundos y de 1 μM en extractos libres de células.

Conclusiones:

Las estrategias de dilución por espín mejoran efectivamente la sensibilidad LC-foto-CIDNP.
Este avance permite la detección rápida de biomoléculas de muy baja concentración.
El método desarrollado es aplicable a medios biológicos complejos como extractos libres de células de E. coli.

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