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Las isomerizaciones cis-trans de los residuos de prolina son clave para las conformaciones de bradicinina

Nicholas A Pierson¹, Liuxi Chen, David H Russell

¹Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.

Journal of the American Chemical Society

|February 5, 2013

Resumen

Los residuos de prolina en la bradicinina (BK) dictan sus poblaciones conformacionales. Las sustituciones de alanina revelan cómo las configuraciones de prolina cis-trans influyen en las estructuras de péptidos y su interconversión en solución.

Área de la Ciencia:

Física Química Física Química es la física de la química.
Química biofísica y bioquímica.
Espectrometría de masas por espectrometría de masas.

Sus antecedentes:

El no péptido bradicinina (BK) exhibe múltiples conformaciones dependiendo de la composición de la solución.
Comprender estas conformaciones es crucial para elucidar el comportamiento y la función de los péptidos.

Objetivo del estudio:

Investigar el papel específico de los residuos de prolina en el establecimiento de la diversidad conformacional de BK.
Para correlacionar el isomerismo cis-trans de la prolina con las estructuras peptídicas observadas.

Principales métodos:

Se empleó la espectrometría de masa de movilidad iónica (IM-MS) para analizar BK y sus análogos.
Se sintetizaron y analizaron siete péptidos análogos con sustituciones de alanina por residuos de prolina.
Se compararon los datos de IM-MS para identificar las diferencias estructurales atribuidas a las configuraciones de prolina.

Principales resultados:

Las distribuciones IM-MS revelaron poblaciones conformacionales distintas para BK y sus análogos.
Las sustituciones de la prolina por la alanina alteraron el paisaje conformacional.
Los datos indican que las combinaciones específicas de formas cis y trans de prolina están asociadas con diferentes estructuras péptidas.

Conclusiones:

Los residuos de prolina, específicamente su isomerismo cis-trans, son determinantes clave de la heterogeneidad conformacional de la bradicinina.
El estudio proporciona asignaciones para poblaciones de péptidos observados basadas en configuraciones de prolina.
Los estudios de activación por colisión demuestran conectividad entre diferentes estados conformacionales, vinculados al isomerismo de la prolina.

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