Summary information and primary citation
- PDB-id
-
8fti;
DSSR-derived features in text and
JSON formats
- Class
- RNA binding protein-RNA
- Method
- cryo-EM (3.5 Å)
- Summary
- cryo-EM structure of the cas13bt3-crrna-target RNA
ternary complex in activated state
- Reference
-
Deng X, Osikpa E, Yang J, Oladeji SJ, Smith J, Gao X, Gao
Y (2023): "Structural
basis for the activation of a compact CRISPR-Cas13
nuclease." Nat Commun, 14,
5845. doi: 10.1038/s41467-023-41501-5.
- Abstract
- The CRISPR-Cas13 ribonucleases have been widely applied
for RNA knockdown and transcriptional modulation owing to
their high programmability and specificity. However, the
large size of Cas13 effectors and their non-specific RNA
cleavage upon target activation limit the adeno-associated
virus based delivery of Cas13 systems for therapeutic
applications. Herein, we report detailed biochemical and
structural characterizations of a compact Cas13 (Cas13bt3)
suitable for adeno-associated virus delivery. Distinct from
many other Cas13 systems, Cas13bt3 cleaves the target and
other nonspecific RNA at internal "UC" sites and is
activated in a target length-dependent manner. The
cryo-electron microscope structure of Cas13bt3 in a fully
active state illustrates the structural basis of Cas13bt3
activation. Guided by the structure, we obtain engineered
Cas13bt3 variants with minimal off-target cleavage yet
maintained target cleavage activities. In conclusion, our
biochemical and structural data illustrate a distinct
mechanism for Cas13bt3 activation and guide the engineering
of Cas13bt3 applications.
