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In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa
Published on: February 17, 2014
La unión al sustrato en la quinoproteína etanol deshidrogenasa de pseudomonas aeruginosa estudiada por resonancia
Christopher W M Kay1, Bina Mennenga, Helmut Görisch
1Institut für Experimentalphysik, Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany.
Journal of the American Chemical Society
|June 2, 2005
Resumen
La pirroloquinolina quinona (PQQ) es un cofactor en las quinoproteínas. Los estudios de resonancia paramagnética de electrones (EPR) muestran que el etanol se une a la Pseudomonas aeruginosa etanol deshidrogenasa (QEDH), lo que proporciona evidencia directa de la interacción del alcohol con las enzimas dependientes de PQQ.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- La biofísica es la biofísica.
- Enzimología Enzimología.
Sus antecedentes:
- La pirroloquinolina quinona (PQQ) es un cofactor de quinona vital en las quinoproteínas.
- Las quinoproteínas, incluida la etanol deshidrogenasa (QEDH), juegan un papel crucial en las reacciones redox biológicas.
- El estudio de las interacciones cofactor-sustrato es clave para comprender los mecanismos de las enzimas.
Objetivo del estudio:
- Para investigar la unión al sustrato en Pseudomonas aeruginosa etanol deshidrogenasa (QEDH).
- Para utilizar la forma de semiquinona paramagnética del cofactor PQQ para estudios de resonancia paramagnética de electrones (EPR).
- Proporcionar evidencia directa de la unión del alcohol a las deshidrogenasas de alcohol dependientes de PQQ.
Principales métodos:
- Se empleó espectroscopia EPR de onda continua de alto campo/alta frecuencia (94 GHz, banda W).
- Se utilizaron simulaciones espectrales para determinar los valores principales del tensor g.
- Comparación de los espectros EPR para QEDH sin sustrato y QEDH unido al etanol.
Principales resultados:
- Los valores principales del g-tensor cambiaron cuando el etanol se unió a QEDH.
- Este desplazamiento indica un cambio en el entorno electrónico alrededor del cofactor PQQ.
- Se obtuvo evidencia directa de unión del etanol a la enzima, incluso con PQQ en forma de semiquinona.
Conclusiones:
- El etanol se une fuertemente a la QEDH dependiente de PQQ.
- El evento de unión altera la polaridad local y la geometría del complejo PQQ-Ca2+.
- Este estudio ofrece la primera evidencia espectroscópica directa de que el alcohol se une a dichas enzimas.
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