RNA targeting unleashes indiscriminate nuclease activity of CRISPR-Cas12a2.
Nature
; 613(7944): 582-587, 2023 01.
Article
in En
| MEDLINE
| ID: mdl-36599980
ABSTRACT
Cas12a2 is a CRISPR-associated nuclease that performs RNA-guided, sequence-nonspecific degradation of single-stranded RNA, single-stranded DNA and double-stranded DNA following recognition of a complementary RNA target, culminating in abortive infection1. Here we report structures of Cas12a2 in binary, ternary and quaternary complexes to reveal a complete activation pathway. Our structures reveal that Cas12a2 is autoinhibited until binding a cognate RNA target, which exposes the RuvC active site within a large, positively charged cleft. Double-stranded DNA substrates are captured through duplex distortion and local melting, stabilized by pairs of 'aromatic clamp' residues that are crucial for double-stranded DNA degradation and in vivo immune system function. Our work provides a structural basis for this mechanism of abortive infection to achieve population-level immunity, which can be leveraged to create rational mutants that degrade a spectrum of collateral substrates.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
RNA
/
CRISPR-Associated Proteins
/
CRISPR-Cas Systems
Language:
En
Journal:
Nature
Year:
2023
Document type:
Article
Affiliation country:
United States