EMD-27179
Structure of Cas12a2 ternary complex
EMD-27179
Single-particle2.74 Å
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Map released: 18/01/2023
Last modified: 12/06/2024
Sample Organism:
synthetic construct,
Sulfuricurvum sp. PC08-66
Sample: Cas12a2 ternary complex
Fitted models: 8d4a (Avg. Q-score: 0.588)
Deposition Authors: Bravo JPK, Taylor DW
Sample: Cas12a2 ternary complex
Fitted models: 8d4a (Avg. Q-score: 0.588)
Deposition Authors: Bravo JPK, Taylor DW
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RNA targeting unleashes indiscriminate nuclease activity of CRISPR-Cas12a2.
Bravo JPK,
Hallmark T
,
Naegle B,
Beisel CL
,
Jackson RN
,
Taylor DW
(2023) Nature , 613 , 582 - 587
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(2023) Nature , 613 , 582 - 587
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.
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.