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El impacto de la protonación en la translocación temprana del factor letal del ántrax: cinética de simulaciones de
Piao Ma1, Alfredo E Cardenas2, Mangesh I Chaudhari3
1Department of Chemistry, University of Texas at Austin , Austin, Texas 78712, United States.
Journal of the American Chemical Society
|October 12, 2017
Resumen
Las simulaciones de dinámica molecular revelan cómo el segmento N-terminal del factor letal (LF) penetra en el canal de ántrax. Los estados de protonación influyen críticamente en este paso inicial, potencialmente irreversible, formando un gancho que bloquea el canal.
Área de la Ciencia:
- La biofísica
- Biología computacional
- La bioquímica
Sus antecedentes:
- El factor letal (FL) es un componente clave de la toxina del ántrax.
- La comprensión de la translocación de LF a través del canal de ántrax es crucial para desarrollar contramedidas.
- El segmento N-terminal de LF inicia el proceso de permeación.
Objetivo del estudio:
- Investigar los mecanismos moleculares de la permeación del segmento N-terminal de la LF a través del canal del ántrax.
- Para aclarar el papel de los estados de protonación de aminoácidos en este proceso.
- Para extraer información cinética sobre la permeación utilizando técnicas avanzadas de simulación.
Principales métodos:
- Simulaciones de dinámica molecular detalladas atómicamente.
- Modelo de disolvente explícito
- Teoría de hito para el análisis cinético en múltiples escalas de tiempo (de nanosegundos a milisegundos).
Principales resultados:
- La cadena N-terminal no estructurada conduce a la permeación LF.
- La permeación inicial es muy sensible a los estados de protonación de los aminoácidos.
- Los altos estados de protonación facilitan el paso a través del canal y la abrazadera phi (φ).
- El evento de permeación inicial puede ser irreversible, creando un "gancho" en la boca del canal.
Conclusiones:
- El evento de permeación inicial dependiente de la protonación es un cuello de botella crítico para la translocación de LF.
- Este mecanismo puede representar un objetivo para inhibir la actividad de la toxina de ántrax.
- Las simulaciones proporcionan información sobre la dinámica de la permeación de proteínas a través de los canales de la membrana.
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