Type II toxin‐antitoxin (TA) systems modulate many essential cellular processes in prokaryotic organisms. Recent studies indicate certain type II antitoxins also transcriptionally regulate other genes, besides neutralizing toxin activity. Herein, we investigated the diverse transcriptional repression properties of type II TA antitoxin PaHigA from Pseudomonas aeruginosa. Biochemical and functional analyses showed that PaHigA recognized variable pseudopalindromic DNA sequences and repressed expression of multiple genes. Furthermore, we presented high resolution structures of apo‐PaHigA, PaHigA‐P_higBA and PaHigA‐P_pa2440 complex, describing how the rearrangements of the HTH domain accounted for the different DNA‐binding patterns among HigA homologues. Moreover, we demonstrated that the N‐terminal loop motion of PaHigA was associated with its apo and DNA‐bound states, reflecting a switch mechanism regulating HigA antitoxin function. Collectively, this work extends our understanding of how the PaHigB/HigA system regulates multiple metabolic pathways to balance the growth and stress response in P. aeruginosa and could guide further development of anti‐TA oriented strategies for pathogen treatment.

中文翻译：

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铜绿假单胞菌抗毒素 HigA 通过识别特定的假回文 DNA 基序作为多种调节因子发挥作用

II 型毒素-抗毒素 (TA) 系统调节原核生物中的许多基本细胞过程。最近的研究表明，除了中和毒素活性外，某些 II 型抗毒素还可以转录调节其他基因。在此，我们研究了来自铜绿假单胞菌的II 型 TA 抗毒素 PaHigA 的多种转录抑制特性。生化和功能分析表明，PaHigA 识别可变的假回文 DNA 序列并抑制多个基因的表达。此外，我们展示了 apo-PaHigA、PaHigA-P _higBA和 PaHigA-P _{pa2440 的}高分辨率结构复杂，描述 HTH 结构域的重排如何解释 HigA 同源物中不同的 DNA 结合模式。此外，我们证明了 PaHigA 的 N 端环运动与其 apo 和 DNA 结合状态相关，反映了调节 HigA 抗毒素功能的开关机制。总的来说，这项工作扩展了我们对 PaHigB/HigA 系统如何调节多种代谢途径以平衡铜绿假单胞菌的生长和应激反应的理解，并可以指导进一步开发以抗 TA 为导向的病原体治疗策略。