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Investigaciones espectroscópicas ópticas de horquillas modelo de hojas beta en una solución acuosa
Jovencio Hilario1, Jan Kubelka, Timothy A Keiderling
1Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor Street, Chicago, IL 60607-7061, USA.
Journal of the American Chemical Society
|June 19, 2003
Resumen
Las horquillas beta diseñadas con secuencias específicas muestran una estructura de hoja beta significativa. Los datos espectroscópicos y las simulaciones confirman la estructura, con (D) Pro-Gly demostrando un motivo de giro superior para la formación mejorada de hojas beta.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- La espectroscopia es una técnica de espectroscopia.
- Química computacional es la química computacional.
Sus antecedentes:
- Las horquillas beta son motivos estructurales cruciales de las proteínas.
- Los estudios de RMN indicaron que los péptidos diseñados poseen una estructura de hoja beta.
- Se incorporaron racimos hidrofóbicos y secuencias específicas (D) Pro-Gly para promover los giros.
Objetivo del estudio:
- Para reportar datos espectroscópicos ópticos para las horquillas beta diseñadas.
- Para comparar la eficacia de (D) Pro-Gly frente a Asn-Gly. girar los motivos.
- Validar los hallazgos espectroscópicos con simulaciones teóricas.
Principales métodos:
- Espectroscopia de la Transformación de Fourier en el infrarrojo (FTIR)
- El dicroísmo circular electrónico (ECD) y el dicroísmo circular vibratorio (VCD) espectroscopia.
- Ab initio cálculos mecánicos cuánticos para simulaciones.
- Estudios de desnaturalización térmica y de clorhidrato de guanidina.
Principales resultados:
- Los espectros FTIR, ECD y VCD se alinean con un alto contenido de hojas beta.
- La secuencia (D) Pro-Gly demostró características espectrales de hoja beta superiores en comparación con Asn-Gly.
- Spectra mostró un acuerdo cualitativo con las simulaciones teóricas, ayudando a las asignaciones de modo.
- Los disolventes mezclados indujeron un aumento de la estructura de la lámina.
- Los estudios de desnaturalización revelaron amplias transiciones de desarrollo, con estados finales distintos para la desnaturalización térmica frente a la caotrópica.
Conclusiones:
- Las horquillas beta diseñadas exhiben una estructura sustancial de hojas beta.
- La secuencia (D) Pro-Gly es un motivo eficaz para promover los giros y la estabilidad de beta-hairpin.
- Los métodos espectroscópicos y computacionales proporcionan una caracterización robusta de la estructura del péptido.
- Las condiciones ambientales (solvente) y los desnaturalizantes influyen en la estructura y estabilidad de la horquilla.
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