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Espectroscopia de resonancia magnética nuclear giratoria de polarización-ángulo-mágico en proteínas sólidas

Etsuko Katoh¹, K Takegoshi, Takehiko Terao

¹Biochemistry Department, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan.

Journal of the American Chemical Society

|March 18, 2004

Resumen

La polarización por ángulo mágico (NOP-MAS) mejora las señales de (13) C en las proteínas de manera más efectiva que la polarización cruzada (CP). Esta técnica permite el análisis cuantitativo y funciona bien para moléculas móviles y muestras con aditivos.

Área de la Ciencia:

Espectroscopia de resonancia magnética nuclear (RMN) en estado sólido.
Química biofísica es la química biofísica.
Determinación de la estructura de las proteínas.

Sus antecedentes:

La polarización cruzada (CP) es una técnica común para mejorar las señales de RMN en muestras sólidas.
Lograr una mejora uniforme de la señal en todos los núcleos (13)C utilizando CP puede ser un desafío.
CP es a menudo ineficaz para moléculas con cierto grado de movilidad.

Objetivo del estudio:

Para evaluar la efectividad de la técnica de polarización-girado de ángulo mágico (NOP-MAS) para proteínas etiquetadas uniformemente con (13) C, (15) N.
Para comparar el rendimiento de NOP-MAS con el método establecido de polarización cruzada (CP).
Para demostrar las ventajas de NOP-MAS para el análisis cuantitativo de RMN y los tipos de muestras desafiantes.

Principales métodos:

Aplicación de la técnica de polarización y giro de ángulo mágico (NOP-MAS) del reactor nuclear.
Utilizando muestras de proteínas etiquetadas uniformemente con (13) C, (15) N.
Comparación de los factores de mejora de la señal y la calidad espectral con la polarización cruzada (CP).

Principales resultados:

NOP-MAS logró un factor de mejora de 1.52.0 por escaneo, significativamente más alto que el CP (<1.0).
NOP-MAS proporcionó una mejora uniforme de la señal (13) C, facilitando las comparaciones cuantitativas.
NOP-MAS demostró eficacia para moléculas algo móviles y efectivamente suprimió las señales de los aditivos no etiquetados.

Conclusiones:

NOP-MAS es una técnica superior a la CP para muchas proteínas etiquetadas uniformemente con (13) C.
NOP-MAS permite mediciones cuantitativas de la intensidad de la señal y es adecuado para diversas muestras de proteínas.
La técnica ofrece ventajas en términos de facilidad de uso bajo giro rápido de ángulo mágico (MAS) y aplicabilidad a sistemas móviles.

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