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-Structure paper
Title | Structural basis for assembly of non-canonical small subunits into type I-C Cascade. |
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Journal, issue, pages | Nat Commun, Vol. 11, Issue 1, Page 5931, Year 2020 |
Publish date | Nov 23, 2020 |
Authors | Roisin E O'Brien / Inês C Santos / Daniel Wrapp / Jack P K Bravo / Evan A Schwartz / Jennifer S Brodbelt / David W Taylor / |
PubMed Abstract | Bacteria and archaea employ CRISPR (clustered, regularly, interspaced, short palindromic repeats)-Cas (CRISPR-associated) systems as a type of adaptive immunity to target and degrade foreign nucleic ...Bacteria and archaea employ CRISPR (clustered, regularly, interspaced, short palindromic repeats)-Cas (CRISPR-associated) systems as a type of adaptive immunity to target and degrade foreign nucleic acids. While a myriad of CRISPR-Cas systems have been identified to date, type I-C is one of the most commonly found subtypes in nature. Interestingly, the type I-C system employs a minimal Cascade effector complex, which encodes only three unique subunits in its operon. Here, we present a 3.1 Å resolution cryo-EM structure of the Desulfovibrio vulgaris type I-C Cascade, revealing the molecular mechanisms that underlie RNA-directed complex assembly. We demonstrate how this minimal Cascade utilizes previously overlooked, non-canonical small subunits to stabilize R-loop formation. Furthermore, we describe putative PAM and Cas3 binding sites. These findings provide the structural basis for harnessing the type I-C Cascade as a genome-engineering tool. |
External links | Nat Commun / PubMed:33230133 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.13 Å |
Structure data | EMDB-22876, PDB-7kha: |
Source |
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Keywords | RNA BINDING PROTEIN/RNA / CRISPR / Cascade / RNA BINDING PROTEIN-RNA complex |