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Dynamic balance of CRISPR-Cas immunity and resistance plasmid anti-immunity mediated by a bifunctional protein AcrIE10.

Waitang Tsui·Yang Yang·Chuning Wang·Dan Li·Yixin Zhang·Xiaoyu Zhao·Jingjing Wu·Ji Guo·Yihua Wang·Xiang Cheng·Xuhang Li·Oksana Kotovskaya·Artem Isaev·Jinbiao Ma·Minggui Wang
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Abstract

Despite targeting by CRISPR-Cas system, antimicrobial resistance plasmids are prevalent in clinical isolates of carbapenem-resistant Klebsiella pneumoniae which represent a major public health threat. A stable co-existence of plasmids and CRISPR-Cas systems is mediated by anti-CRISPR (Acr) proteins. Here, we report that previously identified AcrIE10 encoded by a resistance plasmid combines two functions: it inhibits CRISPR immunity by directly binding Cas7* subunit through its Acr domain, and acts as an Acr-associated (Aca) protein that self-represses the transcription of Acr locus. AcrIE10 is an example of an Aca protein that utilizes N-terminal ribbon-helix-helix (RHH) domain to specifically recognize the inverted repeat (IR) region in its own promoter. Crucially, a dimerization of AcrIE10 dimers is required for the effective binding to the IR and self-repression, while stoichiometry-dependent interaction with Cas7* facilitates transition to de-repressed state. These findings elucidate molecular mechanisms by which AcrIE10 operates as a dual functionAcr-Aca protein to achieve a delicate balance between host CRISPR-Cas immunity and plasmid anti-defense.

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Klebsiella pneumoniaeCRISPR-Cas SystemsPlasmidsBacterial ProteinsPromoter Regions, GeneticDrug Resistance, BacterialGene Expression Regulation, BacterialJournal ArticleResearch Support, Non-U.S. Gov't

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Waitang Tsui, Yang Yang, Chuning Wang, Dan Li, Yixin Zhang, Xiaoyu Zhao, Jingjing Wu, Ji Guo, Yihua Wang, Xiang Cheng, Xuhang Li, Oksana Kotovskaya, Artem Isaev, Jinbiao Ma, Minggui Wang. 2026-08-03. Dynamic balance of CRISPR-Cas immunity and resistance plasmid anti-immunity mediated by a bifunctional protein AcrIE10.. https://doi.org/10.1038/s41467-026-76353-2

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