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Especificidad del ligando modulada por el enlace prolílimoide isomerización Cis/Trans en el dominio Itk SH2: un

Patrick J Breheny¹, Alain Laederach, D Bruce Fulton

¹Department of Biochemistry, Biophysics and Molecular Biology, Program of Bioinformatics and Computational Biology, Iowa State University, Ames, Iowa 50011, USA.

Journal of the American Chemical Society

|December 18, 2003

Resumen

El dominio SH2 de la interleucina-2 tirosina quinasa (Itk) utiliza la isomerización cis/trans para unirse a diferentes ligandos. Este estudio cuantifica las afinidades, revelando preferencias distintas para el dominio SH3 y los ligandos fosfopéptidos.

Área de la Ciencia:

La bioquímica es la bioquímica.
Biología Molecular Biología Molecular
Biología Estructural Biología estructural.

Sus antecedentes:

El dominio de la Interleucina-2 tirosina quinasa (Itk) Src homología 2 (SH2) se une tanto a los péptidos que contienen fosfotirosina como al dominio de la Itk Src homología 3 (SH3).
La especificidad de unión de ligandos está modulada por la isomerización cis/trans del enlace imídico Asn286-Pro287 dentro del dominio Itk SH2.

Objetivo del estudio:

Desarrollar y aplicar un nuevo método para cuantificar las afinidades de ligandos con distintos conformadores del dominio Itk SH2.
Para dilucidar las afinidades de unión diferenciales de los cis y trans conformers del dominio Itk SH2 para sus ligandos conocidos.

Principales métodos:

Utilizó la perturbación de desplazamiento químico y el análisis de volumen de pico cruzado.
Se midieron las afinidades de unión del fosfopéptido y el dominio Itk SH3 a los conformadores cis y trans del dominio Itk SH2.

Principales resultados:

El conformador de enlaces de cis imida mostró una afinidad 3,5 veces mayor para el dominio Itk SH3 en comparación con el transformador.
El transformador exhibió una afinidad cuatro veces mayor por el ligando fosfopeptídeo que el transformador cis.

Conclusiones:

El estudio demuestra cuantitativamente las especificidades diferenciales de unión de ligando de los conformadores de dominio Itk SH2.
La metodología desarrollada ofrece un enfoque general para el análisis de sistemas conformacionalmente heterogéneos con interruptores moleculares.

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