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Measuring G-protein-coupled Receptor Signaling via Radio-labeled GTP Binding
Published on: June 9, 2017
Un modelo de pistón para la señalización transmembrana del receptor de aspartato
K M Ottemann1, W Xiao, Y K Shin
1Department of Molecular and Cell Biology and Department of Chemistry, University of California, Berkeley, CA 94720, USA.
Science (New York, N.Y.)
|September 11, 1999
Resumen
La unión del ligando a los receptores de aspartato bacteriano causa un pequeño movimiento en forma de pistón dentro de las hélices transmembrana. Este pequeño cambio conformacional es amplificado por enzimas acopladas, lo que permite respuestas celulares significativas.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- Biología Estructural Biología estructural.
Sus antecedentes:
- Los receptores de aspartato bacteriano son cruciales para la transducción de señales.
- Comprender los cambios conformacionales del receptor es clave para la propagación de la señal a través de las membranas.
Objetivo del estudio:
- Para dilucidar el mecanismo de propagación del cambio conformacional en los receptores de aspartato bacteriano.
- Para cuantificar los cambios estructurales tras la unión de ligandos.
Principales métodos:
- Etiquetado de espín de nitróxido del receptor de aspartato bacteriano.
- Espectroscopia de resonancia paramagnética de electrones (EPR) para analizar los receptores etiquetados.
- Comparación de espectros en presencia y ausencia de ligando aspartato.
Principales resultados:
- La unión de ligandos indujo un movimiento de tipo pistón de aproximadamente 1 angstrom de una hélice transmembrana en relación con otra.
- Este movimiento se observó dentro de una sola subunidad del receptor.
- Las proteínas asociadas CheA y CheW no afectaron el movimiento inducido por ligando.
Conclusiones:
- El receptor de aspartato bacteriano sufre un pequeño cambio de conformación específico al unirse al ligando.
- La amplificación de este pequeño movimiento por enzimas acopladas es esencial para generar grandes respuestas celulares.
- Este mecanismo pone de relieve la sensibilidad de los sistemas enzimáticos acoplados a receptores.
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