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Isolation of Translating Ribosomes Containing Peptidyl-tRNAs for Functional and Structural Analyses
Published on: February 26, 2011
La formación de enlaces péptidos basados en proteínas por la transferasa de proteínas aminoacil-tRNA
Kazunori Watanabe1, Yukimatsu Toh, Kyoko Suto
1Institute of Biological Resources and Functions, National Institute of Advanced Industrial Sciences and Technology, 1-1-1, Higashi, Tsukuba-shi, Ibaraki 305-8566, Japan.
Nature
|September 25, 2007
Resumen
La leucil/fenilalanil-tRNA proteína transferasa (LF-transferasa) de las eubacterias forma enlaces péptidos mediante un nuevo mecanismo basado en proteínas. Un sistema de relés de electrones facilita la abstracción de protones, lo que permite el ataque nucleofílico para la formación de enlaces péptidos.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
- Enzimología Enzimología.
Sus antecedentes:
- La leucil/fenilalanil-tRNA proteína transferasa (LF-transferasa) de las eubacterias cataliza la formación de enlaces péptidos.
- El mecanismo catalítico preciso de la LF-transferasa seguía siendo en gran medida desconocido.
Objetivo del estudio:
- Para dilucidar el mecanismo catalítico de la formación de enlaces péptidos por la LF-transferasa.
- Para determinar la base estructural de la actividad de la LF-transferasa.
Principales métodos:
- Cristalografía de rayos X para determinar estructuras complejas.
- Estudios de mutagenesis dirigidos al sitio para investigar las funciones catalíticas.
Principales resultados:
- Se determinaron las estructuras de los complejos de LF-transferasa con sustratos y análogos peptídicos.
- Se identificó un relé de electrones que involucra a Asp 186 y Gln 188.
- Este relé facilita la abstracción de protones del N-terminal Arg. del péptido aceptador.
Conclusiones:
- La LF-transferasa emplea un mecanismo catalítico basado en proteínas similar al inverso de la acilación de la serina proteasa.
- El mecanismo identificado explica cómo la LF-transferasa genera un nucleófilo para la formación de enlaces péptidos.
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