Na-binding modes involved in thrombin's allosteric response as revealed by molecular dynamics simulations, correlation networks and Markov modeling.
Research article published in Physical chemistry chemical physics : PCCP (2019)
Abstract
The monovalent sodium ion (Na+) is a critical modulator of thrombin. However, the mechanism of thrombin's activation by Na+ has been widely debated for more than twenty years. Details of the linkage between thrombin and Na+ remain vague due to limited temporal and spatial resolution in experiments. In this work, we combine microsecond scale atomic-detailed molecular dynamics simulations with correlation network analyses and hidden Markov modeling to probe the detailed thermodynamic and kinetic picture of Na+-binding events and their resulting allosteric responses in thrombin. We reveal that ASP189 and ALA190 comprise a stable Na+-binding site (referred as "inner" Na+-binding site) along with the previously known one (referred as "outer" Na+-binding site). The corresponding newly identified Na+-binding mode introduces significant allosteric responses in thrombin's regulatory regions by stabilizing selected torsion angles of residues responsive to Na+-binding. Our Markov model indicates that the bound Na+ prefers to transfer between the two Na+-binding sites when an unbinding event takes place. These results suggest a testable hypothesis of a substrate-driven Na+ migration (ΔG ∼ 1.7 kcal mol-1) from the "inner" Na+-binding site to the "outer" one during thrombin's catalytic activities. The binding of a Na+ ion at the "inner" Na+-binding site should be inferred as a prerequisite for thrombin's efficient recognition to the substrate, which opens a new angle for our understanding of Na+-binding's allosteric activation on thrombin and sheds light on detailed processes in thrombin's activation.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
The monovalent sodium ion (Na+) is a critical modulator of thrombin. However, the mechanism of thrombin's activation by Na+ has been widely debated for more than twenty years.
Por qué esto importa para la hirudoterapia
Este estudio computacional combinó simulaciones de dinámica molecular a escala de microsegundos con análisis de redes de correlación y modelado oculto de Markov para investigar los eventos de unión de sodio y sus respuestas alostéricas resultantes en la trombina. Los investigadores identificaron un nuevo sitio de unión de sodio 'interno' (ASP189, ALA190) junto al sitio 'externo' previamente conocido, proponiendo que la migración de Na+ entre estos sitios durante la actividad catalítica representa un proceso impulsado por el sustrato esencial para el reconocimiento eficiente del sustrato. El resumen no menciona sanguijuelas, hirudoterapia, hirudina ni ningún compuesto derivado de sanguijuelas, y el trabajo es completamente teórico. Este artículo no tiene relevancia defendible para la hirudoterapia o el secretoma de las sanguijuelas.
Citación
Na-binding modes involved in thrombin's allosteric response as revealed by molecular dynamics simulations, correlation networks and Markov modeling.
Xiao et al. · Physical chemistry chemical physics : PCCP, 2019
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Añadido a la biblioteca ASH: May 28, 2026 · Última actualización del sitio: 18 de junio de 2026