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Isolating Myofibrils from Skeletal Muscle Biopsies and Determining Contractile Function with a Nano-Newton Resolution Force Transducer
Published on: May 7, 2020
La fuerza muscular es generada por cabezas de miosina estereospecíficamente unidas a la actina
S Y Bershitsky1, A K Tsaturyan, O N Bershitskaya
1National Institute for Medical Research, Mill Hill, London, UK.
Nature
|July 10, 1997
Resumen
La generación de fuerza muscular implica puentes cruzados de miosina que se unen a la actina. Nuestro estudio muestra que la fuerza aumenta a medida que los puentes cruzados pasan de la unión no específica a la estereospecífica, etiquetando la hélice de actina.
Área de la Ciencia:
- Fisiología muscular y biofísica.
- Mecanismos moleculares de la contracción muscular
Sus antecedentes:
- La fuerza muscular es generada por puentes cruzados de miosina que interactúan con la actina.
- La mayoría de los puentes cruzados de miosina se unen durante la contracción isométrica, pero solo una pequeña fracción se une estereospecíficamente.
Objetivo del estudio:
- Para determinar la fracción de puentes cruzados que contribuyen a la tensión muscular.
- Para investigar los cambios estructurales en los puentes cruzados adjuntos durante la generación de fuerza.
Principales métodos:
- Monitoreo de los patrones de difracción de rayos X en las fibras musculares de rana permeabilizadas.
- La inducción de la tensión aumenta a través de saltos de temperatura (5-6 ° C a 16-19 ° C) en las fibras musculares activadas.
Principales resultados:
- Se observó un aumento de 1,7 veces en la tensión sin cambios significativos en la rigidez de la fibra o reflejos específicos de rayos X.
- Se observó una disminución del 20% en la intensidad de reflexión ecuatorial (1,0) y un aumento del ~13% en la intensidad de la línea de la primera capa de actina.
- Estos cambios indican una transición de los puentes cruzados de un apego no específico a un apego estereospecífico a la actina.
Conclusiones:
- La generación de fuerza muscular está vinculada a una transición de puente cruzado de la unión no específica a la estereospecífica.
- Los puentes cruzados de miosina estereospecíficamente unidos etiquetan específicamente la hélice de actina durante la producción de fuerza.
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