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Bases estructurales para la activación catalítica de la tiocyanato hidrolasa que incluye la modificación de la
Takatoshi Arakawa1, Yoshiaki Kawano, Yoko Katayama
1Department of Biotechnology and Life Science, Graduate School of Technology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
Journal of the American Chemical Society
|September 30, 2009
Resumen
La actividad de la tiocyanato hidrolasa (SCNasa) está determinada por la modificación del ácido cisteínico sulfénico de gammaCys133.3. Esta modificación se produce durante el almacenamiento, mejorando la función de la SCNasa recombinante.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Enzimología Enzimología.
- Biología Estructural Biología estructural.
Sus antecedentes:
- La tiocyanato hidrolasa (SCNase) pertenece a la familia de las nitrilhidratasas.
- Cuenta con un exclusivo centro de cobalto no corrino con dos ligandos de cisteína modificados post-traducionalmente: ácido cisteína-sulfénico (Cys-SO(H)) y cisteína-sulfininato (Cys-SO(2)).
Objetivo del estudio:
- Para investigar el proceso de maduración y los determinantes de actividad de la SCNasa recombinante.
- Para aclarar el papel de las modificaciones de cisteína en la función catalítica de SCNase.
Principales métodos:
- Análisis comparativo de la estructura cristalina de SCNase antes y después del almacenamiento.
- Correlación de la actividad enzimática con el grado de modificación de la cisteína.
Principales resultados:
- La SCNasa recombinante parcialmente madurada mostró activación durante el almacenamiento.
- La modificación Cys-SO(2)(-) de gammaCys131 se completó antes del almacenamiento.
- La modificación Cys-SO(H) de gammaCys133 se produjo durante el almacenamiento y fue crucial para la actividad.
- La oxidación adicional de gammaCys133 a Cys-SO(2)(-) suprimió la actividad de la SCNasa.
Conclusiones:
- La modificación del ácido cisteínico sulfénico de gammaCys133 es crítica para la actividad de la SCNasa.
- La activación de la enzima durante el almacenamiento está relacionada con la modificación in situ de gammaCys133.3.
- La comprensión de estas modificaciones proporciona información sobre los mecanismos de la enzima nitril hidratasa.
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