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Estructura cristalina de la proteína de doble especificidad fosfatasa VHR
J Yuvaniyama1, J M Denu, J E Dixon
1Biophysics Research Division and Department of Biological Chemistry, University of Michigan, Ann Arbor 48109-1055, USA.
Science (New York, N.Y.)
|May 31, 1996
Resumen
La estructura cristalina de la fosfatasa de doble especificidad humana VHR revela un sitio activo poco profundo que permite una amplia hidrólisis del sustrato. Esta estructura proporciona información sobre los andamios conservados y las diferencias de especificidad entre DSP y PTP.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
- Biología Molecular Biología Molecular
Sus antecedentes:
- Las fosfatasas de proteína de doble especificidad (DSP) son reguladores críticos de las vías de señalización celular, incluida la mitogénesis y la progresión del ciclo celular.
- Comprender la base estructural de la actividad de la DSP es esencial para aclarar sus roles en la fisiología normal y la enfermedad.
Objetivo del estudio:
- Determinar la estructura cristalina de alta resolución de la fosfatasa relacionada con H1 (VHR) de la vacuna humana, un DSP clave.
- Para aclarar las características estructurales que rigen la especificidad del sustrato de VHR y compararlo con la proteína tirosina fosfatasas (PTPs).
Principales métodos:
- Se empleó la cristalografía de rayos X para determinar la estructura tridimensional del VHR humano a una resolución de 2.1 angstroms.
- El análisis estructural se centró en la arquitectura del sitio activo y las regiones circundantes para inferir los mecanismos de unión y catalización del sustrato.
Principales resultados:
- La estructura cristalina reveló una bolsa de sitio activo poco profunda en VHR, que facilita la hidrólisis de los residuos fosforilados de serina, treonina y tirosina.
- En contraste, las fosfatasas de proteína tirosina (PTP) poseen sitios activos más profundos, lo que restringe su especificidad a la fosfotirosina.
- Las grietas cargadas positivamente cerca del sitio activo de la VHR sugieren un papel en la unión de sustratos con múltiples sitios de fosforilación.
Conclusiones:
- La estructura de VHR establece un andamio estructural conservado compartido por DSP y PTP.
- Se propone una "región de reconocimiento" distinta en VHR para mediar las diferencias de especificidad de sustrato entre DSP y PTP.
- Esta información estructural proporciona una base para comprender las diversas funciones de las fosfatasas en la regulación celular.
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