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Estructura cristalina del fotosistema II que evoluciona con oxígeno a una resolución de 1.9 Å

Yasufumi Umena¹, Keisuke Kawakami, Jian-Ren Shen

¹Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan.

|April 19, 2011

Resumen

Los investigadores determinaron la estructura cristalina de 1.9 Å del fotosistema II, revelando la disposición detallada del grupo de manganeso y calcio esencial para la oxidación del agua. Esta estructura de alta resolución ilumina el sitio catalítico y los potenciales canales de sustrato de agua.

Área de la Ciencia:

La bioquímica es la bioquímica.
Biología Estructural Biología estructural.
Investigación de fotosíntesis Investigación de fotosíntesis.

Sus antecedentes:

El fotosistema II (PSII) realiza la oxidación fotosintética del agua.
Las estructuras anteriores de PSII (2.93.8 Å) carecían de detalles del centro catalítico de división de agua.

Objetivo del estudio:

Para determinar la estructura cristalina de alta resolución del fotosistema II.
Para dilucidar la estructura detallada del centro catalítico de división de agua.

Principales métodos:

Cristalografía de rayos X con rayos X.
Determinación de la estructura de alta resolución (1.9 Å) del fotosistema II.

Principales resultados:

Estructura atómica detallada del cúmulo Mn{4) CaO{5) y sus ligandos.
Identificación de cinco puentes oxo y cuatro moléculas de agua unidas en el sitio catalítico.
Descubrimiento de más de 1.300 moléculas de agua que forman potenciales canales de protones/agua/oxígeno.

Conclusiones:

La estructura de 1,9 Å proporciona un detalle sin precedentes del centro catalítico del fotosistema II.
Las moléculas de agua identificadas pueden actuar como sustratos para la formación de dioxígeno.
Las redes de agua observadas sugieren canales para el transporte molecular, ayudando al análisis funcional.

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