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La conmutación redox de la adenosina-5'-fosfosulfato quinasa con los precursores de oxígeno atómico fotoactivados
Miao Zhang1, Geoffrey E Ravilious, Leslie M Hicks
1Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, Saint Louis, Missouri 63103, USA.
Journal of the American Chemical Society
|October 3, 2012
Resumen
Los investigadores investigaron cómo una reacción química específica afecta a la Adenosina-5'-fosfosulfato quinasa (APSK, por sus siglas en inglés). Descubrieron que una oxidación fotoinducida inhibe específicamente a APSK formando un enlace disulfuro, alterando su forma monomérica activa a un estado dimérico inhibido.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Fisiología vegetal Fisiología vegetal
- La fotoquímica es la fotoquímica.
Sus antecedentes:
- La adenosina-5'-fosfosulfato quinasa (APSK) es crucial para la asimilación del sulfato en las plantas.
- La actividad de APSK está regulada por un enlace disulfuro intersubunitaria entre Cys86 y Cys119.9.
- El estrés oxidativo puede afectar la función y la regulación de las enzimas.
Objetivo del estudio:
- Para investigar la oxidación específica de la planta APSK por O ((((3) P) generado a partir de 2,8-dihydroxymethyldibenzothiophene S-óxido.
- Para determinar si esta oxidación se dirige al sitio de enlace disulfuro regulador de APSK.
Principales métodos:
- La irradiación de APSK en presencia de 2,8-dihydroxymethyldibenzothiophene S-óxido.
- Análisis de la actividad de APSK y cambios en la estructura cuaternaria después de la irradiación.
- Análisis espectroscópicos y bioquímicos para confirmar la formación de enlaces disulfuro.
Principales resultados:
- La oxidación fotoinducida de APSK se logró utilizando 2,8-dihydroxymethyldibenzothiophene S-oxide.
- Se observó una conversión casi cuantitativa de APSK monomérico activo a APSK dimérico inhibido.
- La evidencia sugiere fuertemente que la formación del enlace disulfuro Cys86-Cys119 medió esta inhibición.
Conclusiones:
- O ((((3) P) puede oxidar e inhibir específicamente el APSK vegetal en su enlace disulfuro regulador.
- Esta oxidación fotoinducida proporciona un método para estudiar la regulación y la función de APSK.
- Comprender este mecanismo ofrece información sobre el metabolismo del azufre de las plantas y la regulación de las enzimas en condiciones oxidativas.
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