Li Cong, Li Siyuan, Song Qinghao, Da Lin-Tai, Xu Jun
State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai, 200240, China.
Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai, 200240, China.
Nucleic Acids Res. 2025 Jan 7;53(1). doi: 10.1093/nar/gkae1289.
Cystathionine-β-synthase (CBS) domains are ubiquitously prevalent in all kingdoms of life. Remarkably, in archaea, proteins consisting of solely CBS domains are widespread. However, the biological functions of CBS proteins in archaea are still unknown. Here, we identified a high hydrostatic pressure regulator (HhpR) that comprises four CBS domains serving as a transcriptional activator via specifically binding to the UAS (upstream activating sequence) motif situated within the promoter region of an operon in a hyperthermophilic archaeon Pyrococcus yayanosii under high hydrostatic pressure (HHP). By combining molecular dynamics simulations, in vitro and in vivo assays, we revealed the potential binding interfaces between HhpR and its specific DNA binding site. Particularly, one stem-loop region in HhpR (termed as 'Arm') was found to play a critical role in regulating the transcription activity, and the 192 position in the Arm region is an essential site in dictating the conformational changes of HhpR at HHP condition. Our work provides novel insights into the structure-function relationship of CBS-containing proteins that participate in archaeal gene regulation as general transcriptional activators.
胱硫醚-β-合酶（CBS）结构域在所有生命王国中普遍存在。值得注意的是，在古菌中，仅由CBS结构域组成的蛋白质很普遍。然而，古菌中CBS蛋白的生物学功能仍然未知。在这里，我们鉴定了一种高静水压调节因子（HhpR），它由四个CBS结构域组成，在高静水压（HHP）下通过特异性结合嗜热古菌雅氏火球菌中一个操纵子启动子区域内的上游激活序列（UAS）基序，作为转录激活因子。通过结合分子动力学模拟、体外和体内实验，我们揭示了HhpR与其特定DNA结合位点之间的潜在结合界面。特别地，发现HhpR中的一个茎环区域（称为“臂”）在调节转录活性中起关键作用，并且臂区域中的第192位是决定HhpR在HHP条件下构象变化的关键位点。我们的工作为作为一般转录激活因子参与古菌基因调控的含CBS蛋白的结构-功能关系提供了新的见解。
