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Arquitectura del procesoma de la pequeña subunidad de la levadura
Malik Chaker-Margot1,2, Jonas Barandun1, Mirjam Hunziker1
1Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, NY 10065, USA.
Science (New York, N.Y.)
|December 17, 2016
Resumen
Este estudio revela la estructura de microscopía criolectrónica del procesoma de la pequeña subunidad (SSU) de la levadura. Los hallazgos ofrecen un marco estructural para comprender el ensamblaje eucariótico del ribosoma y el procesamiento del ARN.
Área de la Ciencia:
- Biología molecular
- Biología estructural
- La bioquímica
Sus antecedentes:
- El procesoma de la subunidad pequeña (SSU) es un complejo de ribonucleoproteína esencial para la biogénesis del ribosoma eucariota.
- Coordina el plegamiento, la escisión y la modificación del ARN pre-ribosómico (ARNr) para formar la pequeña subunidad ribosómica.
Objetivo del estudio:
- Determinar la estructura de alta resolución del procesoma de levadura SSU.
- Para aclarar los mecanismos moleculares que subyacen en el ensamblaje de los ribosomas eucariotas.
Principales métodos:
- Para determinar la estructura se empleó la crio-microscopía electrónica (crio-EM).
- Análisis estructural de alta resolución con una resolución de 5,1 angstroms.
Principales resultados:
- La estructura revela cómo el procesoma SSU, junto con el espaciador transcrito externo de 5' y el ARN nucleolar pequeño U3, forma una plataforma de ensamblaje de ARN-proteína.
- Esta plataforma facilita la maduración coordinada de los dominios de ARNr 18S.
- Un motor molecular central sugiere un mecanismo para cambios conformacionales dentro del complejo.
Conclusiones:
- El estudio proporciona un marco estructural detallado para comprender el ensamblaje de los ribosomas eucariotas en Saccharomyces cerevisiae.
- Los hallazgos ofrecen información sobre la intrincada coordinación del procesamiento del ARN y las interacciones de las proteínas durante la biogénesis del ribosoma.
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