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Single-molecule Imaging of Gene Regulation In vivo Using Cotranslational Activation by Cleavage (CoTrAC)
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Dinámica conformacional de la proteína CooA reguladora de la transcripción estudiada por espectroscopia vibratoria de
I V Rubtsov1, T Zhang, H Nakajima
1School of Materials Science, Japan Advanced Institute of Science and Technology, Tatsunokuchi, Ishikawa 923-1292, Japan. irubtsov@sas.upenn.edu
Journal of the American Chemical Society
|October 11, 2001
Resumen
La proteína CooA es una proteína CooA.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- La espectroscopia es una técnica de espectroscopia.
- Dinámica de las proteínas Dinámica de las proteínas
Sus antecedentes:
- CooA es un regulador de la transcripción de la proteína hemo activada por el monóxido de carbono (CO).
- Comprender la dinámica del CO y los cambios conformacionales de las proteínas es crucial para la función del CooA.
Objetivo del estudio:
- Investigar la dinámica ultrarrápida de la recombinación del monóxido de carbono (CO) y los cambios conformacionales en CooA utilizando espectroscopia avanzada.
- Para determinar el ángulo de unión del CO y rastrear las transiciones conformacionales biológicamente relevantes en el COA.
Principales métodos:
- Se empleó una espectroscopia de sonda de cinco segundos visible-bomba de infrarrojo medio (IR).
- Se utilizaron mediciones de anisotropía para determinar la geometría de unión del CO.
Principales resultados:
- Un blanqueamiento transitorio a ~ 1979 cm (-1) indicó que el CO vuelve a unirse al hemo.
- La recombinación de geminato de CO en CooA (98% de recombinación) fue significativamente más rápida que en mioglobina o hemoglobina, con constantes de tiempo de 56 y 290 ps.
- Se determinó que el ángulo de CO limitado era de ~78 grados en relación con el plano de la porfirina.
- Un desplazamiento espectral con una constante de tiempo de 160 ps sugirió distintas conformaciones de proteínas durante la disociación y reunión de CO.
Conclusiones:
- CooA exhibe una rápida recombinación de CO geminado, más rápido que las proteínas hemo relacionadas.
- El estudio rastreó con éxito cambios conformacionales biológicamente relevantes en CooA, vinculando los cambios espectrales a las conformaciones activas e intermedias.
- Los hallazgos proporcionan información sobre el mecanismo de regulación alostérica de CooA.
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