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Un balanceo de cola de 32 grados en el borde del cepillo miosina I en la liberación de ADP
J D Jontes1, E M Wilson-Kubalek, R A Milligan
1Department of Cell Biology, Scripps Research Institute, La Jolla, California 92037, USA.
Nature
|December 14, 1995
Resumen
La miosina de borde de cepillo I (BBMI) sufre un movimiento significativo de dominio durante su ciclo de ATPasa. Este cambio estructural en BBMI, una miosina no convencional, difiere de la miosina II, lo que sugiere adaptaciones funcionales.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- Biología celular Biología celular.
Sus antecedentes:
- La miosina de borde de cepillo I (BBMI) es una miosina no convencional de una sola cabeza que se encuentra en los microvilli intestinales.
- Posee una cadena pesada (M(r) 119K) y tres cadenas ligeras de calmodulina.
- Se cree que BBMI tiene un papel estructural, pero también exhibe propiedades de ATPasa activada por actina y propiedades de motilidad.
Objetivo del estudio:
- Para investigar la estructura tridimensional de los filamentos de actina decorados con BBMI.
- Para analizar los cambios estructurales en el IMB durante el ciclo de la actomyosina ATPasa.
Principales métodos:
- Mapeo tridimensional de filamentos de actina decorados con BBMI.
- Comparación de estructuras con y sin MgADP.
Principales resultados:
- El dominio motor de BBMI se mantuvo en un estado de rigor.
- El dominio de enlace de cadena ligera exhibió una oscilación significativa (aprox. 32 grados).
- Esto dio lugar a un movimiento de aproximadamente 50-72 Angstroms, que difiere de la miosina II.
Conclusiones:
- Los cambios estructurales durante el ciclo de la actomyosina ATPasa varían entre los diferentes tipos de miosina.
- Estas diferencias probablemente reflejan adaptaciones funcionales especializadas de las miosinas.
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