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Hyperpolarized 13C Metabolic Magnetic Resonance Spectroscopy and Imaging
Published on: December 30, 2016
13C-13C mediciones de la distancia de la anchura de la resonancia rotacional en péptidos uniformemente etiquetados
Ramesh Ramachandran1, Vladimir Ladizhansky, Vikram S Bajaj
1Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA.
Journal of the American Chemical Society
|December 11, 2003
Resumen
El experimento de ancho de resonancia rotacional (R2W) mide con precisión las distancias en sólidos biológicos. Este método supera las limitaciones de las técnicas anteriores, permitiendo mediciones precisas específicas del sitio para sistemas uniformemente etiquetados.
Área de la Ciencia:
- Espectroscopia de resonancia magnética nuclear (RMN) en estado sólido.
- Biología estructural Biología estructural.
- La biofísica es la biofísica.
Sus antecedentes:
- Los experimentos convencionales de resonancia rotacional (R2) miden el intercambio de magnetización a lo largo del tiempo.
- Extraer simultáneamente los parámetros de acoplamiento dipolar y de relajación puede ser un desafío.
- Los efectos de truncamiento dipolar limitan las mediciones de distancia en sólidos uniformemente etiquetados.
Objetivo del estudio:
- Introducir y validar el experimento de ancho de resonancia rotacional (R2W) para medir distancias en sólidos.
- Para demostrar la utilidad de R2W combinado con espectroscopia de correlación de desplazamiento químico 2D 13C-13C.
- Mostrar la aplicabilidad de R2W a sistemas biológicos uniformemente etiquetados superando el truncamiento dipolar.
Principales métodos:
- Utilizó el experimento de ancho de resonancia rotacional de tiempo constante (R2W).
- Intercambio de magnetización medido en función de la frecuencia de giro de la muestra.
- R2W combinado con espectroscopia de correlación de desplazamiento químico 13C-13C bidimensional.
Principales resultados:
- Parámetros de acoplamiento dipolar y de relajación extraídos de forma independiente e inequívoca.
- Efectos de truncamiento dipolar atenuados en experimentos R2W.
- Se midieron con precisión múltiples distancias 13C-13C (3-6 Å) en N-acetil-[U-13C,15N]l-Val-l-Leu con una precisión de +/-0.5 Å.
- Las restricciones de distancia de un modelo de dos giros mostraron una buena concordancia con los datos cristalográficos de rayos X.
Conclusiones:
- Los experimentos R2W son ventajosos para extraer parámetros estructurales y de relajación.
- R2W es aplicable a los sistemas biológicos uniformemente etiquetados, superando el truncamiento dipolar.
- Esta técnica proporciona mediciones de distancia precisas y específicas del sitio para el análisis estructural en estado sólido.
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