Structure Reveals a Mechanism of CRISPR-RNA-Guided Nuclease Recruitment and Anti-CRISPR Viral Mimicry.
Mol Cell
; 74(1): 132-142.e5, 2019 04 04.
Article
em En
| MEDLINE
| ID: mdl-30872121
Bacteria and archaea have evolved sophisticated adaptive immune systems that rely on CRISPR RNA (crRNA)-guided detection and nuclease-mediated elimination of invading nucleic acids. Here, we present the cryo-electron microscopy (cryo-EM) structure of the type I-F crRNA-guided surveillance complex (Csy complex) from Pseudomonas aeruginosa bound to a double-stranded DNA target. Comparison of this structure to previously determined structures of this complex reveals a â¼180-degree rotation of the C-terminal helical bundle on the "large" Cas8f subunit. We show that the double-stranded DNA (dsDNA)-induced conformational change in Cas8f exposes a Cas2/3 "nuclease recruitment helix" that is structurally homologous to a virally encoded anti-CRISPR protein (AcrIF3). Structural homology between Cas8f and AcrIF3 suggests that AcrIF3 is a mimic of the Cas8f nuclease recruitment helix.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pseudomonas aeruginosa
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Proteínas de Bactérias
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Proteínas Virais
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DNA Bacteriano
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RNA Bacteriano
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RNA Guia de Cinetoplastídeos
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Mimetismo Molecular
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Proteínas Associadas a CRISPR
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Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas
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Sistemas CRISPR-Cas
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article