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Estructuras cristalográficas de rayos X de oligómeros de péptidos derivados de la β2-microglobulina

Ryan K Spencer¹, Adam G Kreutzer¹, Patrick J Salveson¹

¹Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States.

Journal of the American Chemical Society

|April 28, 2015

Resumen

Los investigadores visualizaron los oligómeros de proteínas tóxicas utilizando cristalografía de rayos X, revelando cómo se forman las enfermedades amiloides como el Alzheimer. Esta visión estructural de los oligómeros de beta2-microglobulina avanza en la comprensión y las posibles terapias para las enfermedades amiloides.

Área de la Ciencia:

Biología estructural Biología estructural.
La bioquímica es la bioquímica.
La medicina molecular es una medicina molecular.

Sus antecedentes:

Las enfermedades amiloides (por ejemplo, Alzheimer, Parkinson, diabetes tipo II) están relacionadas con los oligómeros de proteínas solubles tóxicos.
La falta de estructuras de resolución atómica de los oligómeros de péptido/proteína amiloidogénicos dificulta la comprensión y el desarrollo terapéutico.

Objetivo del estudio:

Para determinar las estructuras cristalográficas de rayos X de oligómeros formados por péptidos macrocíclicos que contienen secuencias de beta2-microglobulina (β2m).
Aclarar los principios de ensamblaje y la diversidad estructural de los oligómeros del péptido amiloidogénico.

Principales métodos:

Se empleó cristalografía de rayos X para determinar las estructuras de siete ensamblajes oligoméricos diferentes.
Se sintetizaron y analizaron péptidos macrocíclicos que incorporan la secuencia β2m63-69 y aminoácidos N-metilo.

Principales resultados:

Se caracterizaron estructuralmente tres familias de oligómeros (hexámero, octámero, dodecámero), revelando temas comunes de asociación de subunidades de dimero y trímero que forman un núcleo hidrofóbico.
Se ilustró la diversidad estructural y el impacto de las mutaciones en el tamaño y la topología de los oligómeros.
Un experimento de cocristalización demostró que una especie de péptido puede influir en la oligomerización de otra.

Conclusiones:

Las estructuras determinadas proporcionan conocimientos sin precedentes a nivel atómico sobre la formación de oligómeros de péptidos amiloidogénicos.
Estos hallazgos ofrecen una base para comprender la base estructural de las enfermedades amiloides y para diseñar intervenciones específicas.
El estudio pone de relieve el potencial de diversas estructuras oligoméricas a partir de una sola secuencia de péptido y la influencia de las interacciones intermoleculares.

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