A bacterial Argonaute with noncanonical guide RNA specificity.
Proc Natl Acad Sci U S A
; 113(15): 4057-62, 2016 Apr 12.
Article
em En
| MEDLINE
| ID: mdl-27035975
ABSTRACT
Eukaryotic Argonaute proteins induce gene silencing by small RNA-guided recognition and cleavage of mRNA targets. Although structural similarities between human and prokaryotic Argonautes are consistent with shared mechanistic properties, sequence and structure-based alignments suggested that Argonautes encoded within CRISPR-cas [clustered regularly interspaced short palindromic repeats (CRISPR)-associated] bacterial immunity operons have divergent activities. We show here that the CRISPR-associated Marinitoga piezophila Argonaute (MpAgo) protein cleaves single-stranded target sequences using 5'-hydroxylated guide RNAs rather than the 5'-phosphorylated guides used by all known Argonautes. The 2.0-Å resolution crystal structure of an MpAgo-RNA complex reveals a guide strand binding site comprising residues that block 5' phosphate interactions. Using structure-based sequence alignment, we were able to identify other putative MpAgo-like proteins, all of which are encoded within CRISPR-cas loci. Taken together, our data suggest the evolution of an Argonaute subclass with noncanonical specificity for a 5'-hydroxylated guide.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
/
RNA Guia de Cinetoplastídeos
/
Proteínas Argonautas
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2016
Tipo de documento:
Article