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Oligómeros peptoides con cadenas laterales alfa-quirales y aromáticas: efectos de la longitud de la cadena en la
C W Wu1, T J Sanborn, R N Zuckermann
1Department of Chemical Engineering, Northwestern University, Evanston, Illinois 60208, USA.
Journal of the American Chemical Society
|July 18, 2001
Resumen
Los oligómeros del peptoide quiral (glicina sustituida por N) forman hélices estables. Su estructura helicoidal y conformación secundaria dependen de la longitud de la cadena, con hélices estables que forman alrededor de 13 residuos.
Área de la Ciencia:
- Química supramolecular de las moléculas.
- Química orgánica es la química orgánica.
- Ciencia de los Biomateriales Ciencia de los Biomateriales.
Sus antecedentes:
- Las glicinas sustituidas por N (peptoides) pueden formar hélices estables sin quiralidad de la columna vertebral o enlaces de hidrógeno.
- La estabilidad helicoidal está influenciada por la evitación estérica y la repulsión electrostática.
- Las hélices peptídicas exhiben distintos espectros de dicroísmo circular (CD) similares a las hélices alfa-peptídicas.
Objetivo del estudio:
- Investigar el impacto de la longitud, concentración y temperatura de los oligómeros en la estructura secundaria quiral de los homooligómeros peptoides organo-solubles.
- Determinar la longitud mínima de la cadena requerida para la formación de una hélice peptoide estable.
- Para evaluar el comportamiento de agregación de estas hélices peptoides en solución.
Principales métodos:
- Estudio sistemático mediante espectroscopia de dicroísmo circular (CD).
- Síntesis y análisis de oligómeros de (R) -N- ((1-feniletil) glicina (Nrpe) con longitudes de 3 a 20 monómeros.
- Variar la concentración y la temperatura de los oligómeros para observar los cambios estructurales.
Principales resultados:
- Se observó una evolución significativa en las características espectrales de CD para los oligómeros de Nrpe entre 4 y 12 residuos.
- Este cambio espectral se atribuye a una población dependiente de la longitud de la cadena de conformadores con enlaces cis/transamídicos.
- Las hélices estables de poli ((Nrpe) requieren una longitud mínima de la cadena de aproximadamente 13 residuos.
- El hexámero de Nrpe no mostró cambios de CD dependientes de la concentración, lo que indica un comportamiento monomérico en solución.
Conclusiones:
- La formación y la estabilidad de la hélice peptoide son críticamente dependientes de la longitud de la cadena oligomérica.
- Los cambios espectrales observados en el CD reflejan transiciones en la estructura secundaria relacionadas con las configuraciones de enlaces amídicos.
- Estos hallazgos son cruciales para el diseño de peptoides biomiméticos con estructuras helicoidales estables.
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