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Purification and Aggregation of the Amyloid Precursor Protein Intracellular Domain

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La proteína precursora amiloide tiene un dominio transmembrana flexible y se une al colesterol

Paul J Barrett¹, Yuanli Song, Wade D Van Horn

¹Department of Biochemistry, Center for Structural Biology and Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN 37232 USA.

Science (New York, N.Y.)

|June 2, 2012

Resumen

Los investigadores descubrieron la estructura de C99, un fragmento de proteína clave en la enfermedad de Alzheimer. Este hallazgo revela cómo el colesterol se une al C99, lo que podría guiar nuevas estrategias terapéuticas para la enfermedad de Alzheimer.

Área de la Ciencia:

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

Sus antecedentes:

La enfermedad de Alzheimer está relacionada con los polipéptidos amiloide-beta (Aβ).
C99 es el precursor de Aβ, escindido por γ-secretasa.
Comprender la estructura y las interacciones de C99 es crucial para la investigación de la enfermedad de Alzheimer.

Objetivo del estudio:

Para aclarar las características estructurales de C99.9.
Para identificar los sitios de unión del colesterol en C99.9.
Proporcionar conocimientos mecanicistas sobre el papel del colesterol en la amiloidogénesis.

Principales métodos:

Espectroscopía por resonancia magnética nuclear (RMN). espectroscopia por resonancia magnética nuclear (RMN). espectroscopia por resonancia magnética nuclear (RMN). espectroscopia por resonancia magnética nuclear (RMN). espectroscopia por resonancia magnética nuclear (RMN). espectroscopia por resonancia magnética nuclear (RMN). espectroscopia por resonancia magnética nuclear (RMN).
Espectroscopía por resonancia paramagnética de electrones (EPR). espectroscopia de resonancia paramagnética de electrones (EPR). espectroscopia de resonancia paramagnética de electrones (EPR). espectroscopia de resonancia paramagnética de electrones (EPR). espectroscopia de resonancia paramagnética de electrones (EPR). espectroscopia de resonancia paramagnética de electrones (EPR).
Pruebas de unión del colesterol (titulación).

Principales resultados:

El extremo extracelular N del C99 presenta una hélice N y un bucle N.
El dominio transmembranar (TMD) es una hélice alfa flexible y curva.
Se identificó un sitio de unión al colesterol, que involucra motivos GXXXG enterrados en la membrana.
La unión al colesterol está relacionada con los motivos GXXXG, conocidos por su papel en la oligomerización de las proteínas.

Conclusiones:

La estructura determinada de C99 explica su idoneidad para la escisión de la γ-secretasa.
La unión del colesterol a C99, mediada por motivos GXXXG, ofrece una visión mecánica del papel del colesterol en la promoción de la amiloidogénesis.
Estos hallazgos pueden informar el desarrollo de nuevas terapias para la enfermedad de Alzheimer.

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