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Conocimientos mecánicos sobre la quinasa LsrK requerida para la activación de la detección de quórum del
Jie Zhu1, Mark S Hixon, Daniel Globisch
1The Skaggs Institute for Chemical Biology and Department of Chemistry and the Worm Institute for Research and Medicine (WIRM), the Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA.
Journal of the American Chemical Society
|May 16, 2013
Resumen
Los investigadores caracterizaron la quinasa LsrK, esencial para la detección de quórum bacteriana. Ellos aclararon su mecanismo cinético e interacciones con el sustrato, proporcionando una base para atacar bacterias patógenas.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Microbiología Microbiología.
- Enzimología Enzimología.
Sus antecedentes:
- LsrK es una quinasa crítica en las bacterias entéricas, que fosforila la 4,5-dihidroxi-2,3-pentanediona (DPD) para la detección de quórum de tipo II (AI-2).
- Esta fosforilación es vital para el secuestro citoplasmático de AI-2 y la regulación de los genes relacionados con AI-2 en el desarrollo del quórum bacteriano.
- Los detalles cinéticos de LsrK, cruciales para el sistema de detección de quórum del DPD, no se habían informado anteriormente.
Objetivo del estudio:
- Para determinar los parámetros cinéticos de estado estacionario de la enzima LsrK.
- Para dilucidar el mecanismo cinético de la fosforilación catalizada por LsrK.
- Para investigar el perfil de sustrato de LsrK con DPD e identificar posibles objetivos de moléculas reguladoras.
Principales métodos:
- Desarrollo de un ensayo espectrofotométrico continuo UV-vis para la medición de la actividad de LsrK.
- Análisis cinético en estado de equilibrio utilizando ATP y DPD como sustratos.
- Perfilado de sustrato de LsrK con varios análogos de DPD.
Principales resultados:
- El mecanismo cinético se determinó como ordenado por el equilibrio rápido, con la unión de ATP primero.
- Se establecieron los parámetros cinéticos clave: kcat (7.4 ± 0.6 s-1), Km, ATP (150 ± 30 μM) y Km, DPD (1.0 ± 0.2 mM).
- Se observó una desconexión bioquímica entre los ensayos de reporter basados en células y el ensayo de la enzima LsrK con respecto a la actividad del sustrato DPD.
Conclusiones:
- El estudio proporciona la primera caracterización cinética de LsrK, revelando su mecanismo y parámetros.
- Los hallazgos destacan la importancia de LsrK y ofrecen una base para diseñar moléculas para inhibir la detección de quórum AI-2 en patógenos.
- La discrepancia observada en el perfil del sustrato justifica una mayor investigación de las vías de señalización de AI-2.
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