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Protein WISDOM: A Workbench for In silico De novo Design of BioMolecules
Published on: July 25, 2013
Un modelo para la interacción enzima-sustrato en la alanina racemasa.
M J Ondrechen1, J M Briggs, J A McCammon
1Department of Chemistry, Northeastern University, Boston, Massachusetts 02115-5000, USA.
Journal of the American Chemical Society
|July 18, 2001
Resumen
Este estudio modela la alanina racemasa, revelando estados de carga inusuales en residuos clave como Tyr265' y Lys39. Estos hallazgos apoyan sus funciones como bases catalíticas en la conversión de L-alanina y D-alanina, ayudando a comprender el mecanismo enzimático.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología computacional Biología computacional.
- La cinética de las enzimas.
Sus antecedentes:
- La alanina racemasa (ALR) es crucial para la síntesis de la pared celular bacteriana.
- Comprender el mecanismo catalítico de la ALR es clave para el desarrollo de inhibidores selectivos.
- Estudios previos sugieren que residuos específicos actúan como bases catalíticas, pero sus estados de ionización requieren una aclaración.
Objetivo del estudio:
- Desarrollar un modelo teórico del complejo alanina racemasa.
- Para predecir los estados de ionización y los potenciales electrostáticos de los residuos clave.
- Para aclarar las funciones de los residuos específicos en el mecanismo catalítico de ALR.
Principales métodos:
- Modelado teórico del complejo enzima-sustrato-cofactor.
- Cálculo de los potenciales electrostáticos.
- Predicción de los valores de pKa y los estados de ionización para grupos ionizables.
Principales resultados:
- Se predijeron estados de carga inusuales para Tyr265 (pKa=7.9) y Lys39.9.
- Se predijo que Tyr265 estaría en forma de fenolato a pH fisiológico, lo que respalda su papel como base catalítica.
- Se predijo que Lys39 estaría en forma de amina no protonada, lo que permite su función como base catalítica.
- Cys311 (pKa=5.8) muestra una carga negativa significativa a un pH de 7.0.
- La baja carga de Lys129 apoya la evidencia experimental de carbamilación.
Conclusiones:
- La enzima estabiliza la carga negativa en el sitio activo.
- Los estados de ionización predichos se alinean con la evidencia experimental para las funciones de residuos catalíticos.
- Los hallazgos proporcionan información para el diseño de inhibidores selectivos de la ALR.
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