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Protonación acoplada por configuración de la poliprolina-7

Liuqing Shi¹, Alison E Holliday², Neelam Khanal¹

¹†Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States.

Journal of the American Chemical Society

|June 28, 2015

Resumen

Este estudio revela cómo las interacciones de disolventes y la termodinámica influyen en la estructura y función biomolecular. Se observó una reacción lenta de transferencia de protones durante la conversión de la hélice de poliprolina-I a la hélice de poliprolina-II en una mezcla de propanol: agua.

Área de la Ciencia:

La bioquímica es la bioquímica.
Física Química Física Química es la física de la química.
La termodinámica es la termodinámica.

Sus antecedentes:

Las interacciones entre biomoléculas y disolventes regulan críticamente la estructura y función de las proteínas.
La termodinámica de estas interacciones, particularmente su influencia en la entropía conformacional, sigue siendo poco comprendida.

Objetivo del estudio:

Para investigar la termodinámica de las interacciones entre biomoléculas y disolventes.
Para dilucidar la influencia de estas interacciones en la entropía conformacional y la dinámica de transferencia de protones.

Principales métodos:

Se realizaron mediciones de cinética y equilibrio a diferentes temperaturas.
Análisis de las reacciones de transferencia de protones que involucran hélices de poliprolina en un sistema de disolvente de propanol: agua.

Principales resultados:

Se observó una reacción lenta de transferencia de protones junto con una conversión de hélice de poliprolina-I (PPI) a hélice de poliprolina-II (PPII).
Se determinaron los parámetros termodinámicos (ΔG, ΔH, ΔS) para los estados generales y de transición de la transferencia de protones.
También se caracterizó una vía no protonante menor, que produce valores termodinámicos distintos.

Conclusiones:

El estudio cuantifica la termoquímica de la transferencia de protones y la conversión de hélices en un sistema de disolventes mixtos.
La transferencia de protones extraordinariamente lenta se atribuye al acoplamiento de configuración a través de un estado de transición similar al PPI.
Los hallazgos proporcionan información sobre la regulación de la transferencia de protones influenciada por la composición del disolvente y la conformación biomolecular.

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