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La anómala distribución de intensidad de las amidas infrarrojas I en hojas beta de péptidos etiquetados
1Department of Chemistry (M/C 111), University of Illinois at Chicago, 845 West Taylor Street, Room 4500 SES, Chicago, IL 60607-7061, USA.
Journal of the American Chemical Society
|June 21, 2001
Resumen
Las estructuras de láminas beta multirramadas en péptidos causan una intensidad anómala de los espectros de absorción infrarroja. Este efecto, observado en péptidos etiquetados isotópicamente, crece con el tamaño de la hoja, lo que ayuda en los estudios de dinámica de plegado de la hoja beta.
Área de la Ciencia:
- Química computacional es la química computacional.
- La espectroscopia es una técnica de espectroscopia.
- La biofísica es la biofísica.
Sus antecedentes:
- Los espectros de absorción infrarroja de amida I son cruciales para el estudio de las estructuras secundarias de los péptidos.
- Estudios previos informaron de una intensidad anómala para la amida I desplazada isotópicamente en péptidos etiquetados.
Objetivo del estudio:
- Para simular espectros de absorción infrarrojos de amida I para péptidos isotópicamente sustituidos en conformaciones de hojas beta antiparalelas.
- Para dilucidar la causa de la intensidad anómala en péptidos etiquetados con (13) C.
Principales métodos:
- Ab initio cálculos de campos de fuerza y tensores polares atómicos.
- Simulación de espectros de absorción de infrarrojos para péptidos con un número variable de hebras de hoja beta antiparalela (n=2-5).
Principales resultados:
- La intensidad anómala en los péptidos etiquetados con (13) C se atribuye a la formación de láminas beta multistranded.
- La división del modo de amida I y la mejora de la intensidad aumentan con el tamaño de la hoja beta.
- Las transiciones más fuertes implican modos acoplados en fase de amidas etiquetadas en hebras internas de hojas más grandes.
Conclusiones:
- Las estructuras de hojas beta antiparalelas multirramadas explican la anómala intensidad de IR en péptidos isotópicamente sustituidos.
- Los hallazgos proporcionan una comprensión detallada de los mecanismos de intensidad de IR en péptidos etiquetados.
- Este conocimiento permite el diseño de sondas específicas del sitio para la dinámica de plegado de hojas beta.
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