8DC2 image
Entry Detail
PDB ID:
8DC2
EMDB ID:
Title:
Cryo-EM structure of CasLambda (Cas12l) bound to crRNA and DNA
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2022-06-15
Release Date:
2022-12-14
Method Details:
Experimental Method:
Resolution:
2.99 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:CasLambda
Chain IDs:A
Chain Length:756
Number of Molecules:1
Biological Source:uncultured virus
Polymer Type:polyribonucleotide
Description:RNA (51-MER)
Chain IDs:B
Chain Length:52
Number of Molecules:1
Biological Source:uncultured virus
Polymer Type:polydeoxyribonucleotide
Description:DNA TS
Chain IDs:C
Chain Length:46
Number of Molecules:1
Biological Source:uncultured virus
Polymer Type:polydeoxyribonucleotide
Description:DNA NTS
Chain IDs:D
Chain Length:46
Number of Molecules:1
Biological Source:uncultured virus
Ligand Molecules
Primary Citation
Diverse virus-encoded CRISPR-Cas systems include streamlined genome editors.
Cell 185 4574 4586.e16 (2022)
PMID: 36423580 DOI: 10.1016/j.cell.2022.10.020

Abstact

CRISPR-Cas systems are host-encoded pathways that protect microbes from viral infection using an adaptive RNA-guided mechanism. Using genome-resolved metagenomics, we find that CRISPR systems are also encoded in diverse bacteriophages, where they occur as divergent and hypercompact anti-viral systems. Bacteriophage-encoded CRISPR systems belong to all six known CRISPR-Cas types, though some lack crucial components, suggesting alternate functional roles or host complementation. We describe multiple new Cas9-like proteins and 44 families related to type V CRISPR-Cas systems, including the Casλ RNA-guided nuclease family. Among the most divergent of the new enzymes identified, Casλ recognizes double-stranded DNA using a uniquely structured CRISPR RNA (crRNA). The Casλ-RNA-DNA structure determined by cryoelectron microscopy reveals a compact bilobed architecture capable of inducing genome editing in mammalian, Arabidopsis, and hexaploid wheat cells. These findings reveal a new source of CRISPR-Cas enzymes in phages and highlight their value as genome editors in plant and human cells.

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Primary Citation of related structures