Summary information and primary citation
- PDB-id
-
8gaf;
SNAP-derived features in text and
JSON formats
- Class
- hydrolase-RNA
- Method
- cryo-EM (3.64 Å)
- Summary
- Exploiting activation and inactivation mechanisms in
type i-c crispr-cas3 for genome editing applications
- Reference
-
Hu C, Myers MT, Zhou X, Hou Z, Lozen ML, Nam KH, Zhang Y,
Ke A (2024): "Exploiting
activation and inactivation mechanisms in type I-C
CRISPR-Cas3 for genome-editing applications."
Mol.Cell, 84, 463-475.e5. doi:
10.1016/j.molcel.2023.12.034.
- Abstract
- Type I CRISPR-Cas systems utilize the RNA-guided
Cascade complex to identify matching DNA targets and the
nuclease-helicase Cas3 to degrade them. Among the seven
subtypes, type I-C is compact in size and highly active in
creating large-sized genome deletions in human cells. Here,
we use four cryoelectron microscopy snapshots to define its
RNA-guided DNA binding and cleavage mechanisms in high
resolution. The non-target DNA strand (NTS) is accommodated
by I-C Cascade in a continuous binding groove along the
juxtaposed Cas11 subunits. Binding of Cas3 further traps a
flexible bulge in NTS, enabling NTS nicking. We identified
two anti-CRISPR proteins AcrIC8 and AcrIC9 that strongly
inhibit Neisseria lactamica I-C function. Structural
analysis showed that AcrIC8 inhibits PAM recognition
through allosteric inhibition, whereas AcrIC9 achieves so
through direct competition. Both Acrs potently inhibit
I-C-mediated genome editing and transcriptional modulation
in human cells, providing the first off-switches for type I
CRISPR eukaryotic genome engineering.
