8D4A

Cas12a2 quaternary complex

Summary for 8D4A

• Entry DOI: 10.2210/pdb8d4a/pdb
• EMDB information: 27179
• Descriptor: OrfB_Zn_ribbon domain-containing protein, RNA (41-MER), RNA (28-MER), ... (8 entities in total)
• Functional Keywords: cas12a2, crispr, nuclease, dna binding protein-rna-dna complex, dna binding protein/rna/dna
• Biological source: Sulfuricurvum sp. PC08-66; More
• Total number of polymer chains: 5
• Total formula weight: 172074.41

Authors

Bravo, J.P.K.,Taylor, D.W. (deposition date: 2022-06-01, release date: 2023-01-18, Last modification date: 2025-05-28)

Primary citation

Bravo, J.P.K.,Hallmark, T.,Naegle, B.,Beisel, C.L.,Jackson, R.N.,Taylor, D.W.
RNA targeting unleashes indiscriminate nuclease activity of CRISPR-Cas12a2.
Nature, 613:582-587, 2023

PubMed 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 infection. 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.

PubMed: 36599980
DOI: 10.1038/s41586-022-05560-w

Experimental method

ELECTRON MICROSCOPY (2.74 Å)