The cryo-EM structure of a ribosome-Ski2-Ski3-Ski8 helicase complex.
Science
; 354(6318): 1431-1433, 2016 12 16.
Article
em En
| MEDLINE
| ID: mdl-27980209
ABSTRACT
Ski2-Ski3-Ski8 (Ski) is a helicase complex functioning with the RNA-degrading exosome to mediate the 3'-5' messenger RNA (mRNA) decay in turnover and quality-control pathways. We report that the Ski complex directly associates with 80S ribosomes presenting a short mRNA 3' overhang. We determined the structure of an endogenous ribosome-Ski complex using cryo-electron microscopy (EM) with a local resolution of the Ski complex ranging from 4 angstroms (Å) in the core to about 10 Å for intrinsically flexible regions. Ribosome binding displaces the autoinhibitory domain of the Ski2 helicase, positioning it in an open conformation near the ribosomal mRNA entry tunnel. We observe that the mRNA 3' overhang is threaded directly from the small ribosomal subunit to the helicase channel of Ski2, primed for ongoing exosome-mediated 3'-5' degradation.
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Bases de dados:
MEDLINE
Assunto principal:
Saccharomyces cerevisiae
/
Proteínas Nucleares
/
DNA Helicases
/
Estabilidade de RNA
/
Proteínas de Saccharomyces cerevisiae
/
Subunidades Ribossômicas Maiores de Eucariotos
/
Complexo Multienzimático de Ribonucleases do Exossomo
Idioma:
En
Revista:
Science
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Alemanha