Mechanism of DNA degradation by CBASS Cap5 endonuclease immune effector
Abstract Bacterial CBASS immune defense systems commonly kill virally infected cells by degrading genomic DNA in a form of cell suicide or abortive infection. We present a high-resolution structure of the CBASS effector Cap5, activated by a cyclic nucleotide, in the act of digesting DNA via tetramer...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-06-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-025-60484-z |
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| Summary: | Abstract Bacterial CBASS immune defense systems commonly kill virally infected cells by degrading genomic DNA in a form of cell suicide or abortive infection. We present a high-resolution structure of the CBASS effector Cap5, activated by a cyclic nucleotide, in the act of digesting DNA via tetrameric HNH endonuclease domains. Two HNH domains are in a catalytically active state for cleavage of the DNA strands, whereas the other two HNH domains are in a topologically distinct catalytically inactive state for simply DNA binding. The four HNH domains track one face of the DNA and mark an enzyme that acts as a stand-alone non-specific nuclease. We also show that chromosomally encoded CBASS Cap5 can be extrinsically activated by a cyclic nucleotide, as a step towards potential antibiotics. |
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| ISSN: | 2041-1723 |