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La agregación de los péptidos anfipáticos (AAKA) n en hojas beta antiparalelas
Thomas J Measey1, Reinhard Schweitzer-Stenner
1Department of Chemistry, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
Journal of the American Chemical Society
|October 13, 2006
Resumen
Los péptidos diseñados para formar hélices se autoensamblan sorprendentemente en hidrogeles con estructuras de hoja beta. Esta inesperada formación de hojas beta ocurre incluso con residuos de lisina cargados positivamente, desafiando las expectativas típicas de autoensamblaje de péptidos.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Ciencia de los materiales Ciencia de los materiales.
- Química supramolecular de las moléculas.
Sus antecedentes:
- Se predice que los péptidos con unidades de repetición anfipáticas (Ac-(AAKA) n-NH2) formarán estructuras helicoidales.
- Las proyecciones de la rueda helicoidal indican una naturaleza anfipática para estos péptidos Ac-(AAKA) n-NH2.
- En general, se espera que los números de residuos más altos favorezcan la formación de hélices en soluciones acuosas.
Objetivo del estudio:
- Para investigar el comportamiento de autoensamblaje de péptidos Ac-(AAKA) n-NH2 en soluciones acuosas.
- Determinar la estructura secundaria adoptada por estos péptidos en diferentes concentraciones.
- Comprender los factores que rigen el autoensamblaje de péptidos en estructuras de orden superior.
Principales métodos:
- Se utilizó la espectroscopia de dicroísmo circular (ECD) para evaluar la estructura secundaria.
- Las concentraciones de péptidos se variaron para observar los efectos en el autoensamblaje.
- La formación de hidrogel se observó macroscópicamente.
Principales resultados:
- Los péptidos Ac-(AAKA) 4-NH2 y Ac-(AAKA) 3-NH2 mostraron cierto contenido helicoidal a concentraciones milimolares.
- Sorprendentemente, en concentraciones centimolares, estos péptidos formaban hidrogeles.
- Los hidrogeles se caracterizaban por una conformación de hoja beta antiparalela, contrariamente a las expectativas de la hélice.
Conclusiones:
- Los péptidos anfipáticos Ac-(AAKA) n-NH2 pueden adoptar una conformación de hoja beta antiparalela.
- Estos péptidos se autoensamblan en hidrogeles en concentraciones más altas, anulando las tendencias helicoidales.
- La formación de estructuras de hojas beta es inesperada dada la presencia de residuos de lisina cargados.
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