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Asignaciones de las resonancias de RMN de carbono para la ubiquitina microcristalina
Tatyana I Igumenova1, Ann E McDermott, Kurt W Zilm
1Department of Chemistry, Columbia University, 3000 Broadway MC 3113, New York, New York 10027, USA.
Journal of the American Chemical Society
|May 27, 2004
Resumen
La espectroscopia NMR 2D de estado sólido efectivamente correlacionó los cambios químicos del carbono en la ubiquitina. Este método identificó sistemas de espín para más de la mitad de las cadenas laterales de aminoácidos, permitiendo asignaciones específicas del sitio.
Área de la Ciencia:
- Espectroscopia de Resonancia Magnética Nuclear (RMN) de estado sólido Espectroscopia de Resonancia Magnética Nuclear (RMN) de estado sólido Espectroscopia de estado sólido
- Determinación de la estructura de las proteínas Determinación de la estructura de las proteínas
- La biofísica es la biofísica.
Sus antecedentes:
- La RMN en estado sólido es crucial para analizar las estructuras de proteínas en estados no cristalinos o microcristalinos.
- La correlación entre la columna vertebral del carbono y los desplazamientos químicos de la cadena lateral proporciona información estructural detallada.
Objetivo del estudio:
- Desarrollar y aplicar un método de espectroscopia 2D de RMN de estado sólido para correlacionar los desplazamientos químicos del carbono en la ubiquitina microcristalina.
- Evaluar la eficiencia de la transferencia de magnetización para identificar las correlaciones carbono-carbono.
Principales métodos:
- Utilizada uniformemente ubiquitina microcristalina enriquecida con (13) C, (((15) N. Utilizada uniformemente en la ubiquitina microcristalina enriquecida con (13) C, (((15) N. Utilizada uniformemente en la ubiquitina microcristalina enriquecida con (13) C, (((15) N.
- Empleó altas intensidades de campo magnético (frecuencia de protones de 800 MHz) y giro de muestras de ángulo mágico (20 kHz).
- Resonancia rotacional dipolar asistida (DARR) aplicada con un tiempo de mezcla de 20 ms para la transferencia de magnetización homonuclear.
Principales resultados:
- Se lograron anchuras estrechas de líneas de carbono (0,5-0,8 ppm) que permiten un análisis espectral detallado.
- Se observaron eficiencias moderadas de transferencia de carbono-carbono de un enlace (~14%) y correlaciones más débiles de dos enlaces (~4%).
- Identificaron con éxito sistemas de espín para más del 50% de las cadenas laterales de aminoácidos.
Conclusiones:
- La secuencia DARR proporciona un método eficiente para obtener correlaciones de carbono de un y dos enlaces en RMN de estado sólido.
- Este enfoque facilita las asignaciones específicas del sitio en las proteínas, complementando otras técnicas de RMN.
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