Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan.
Protein Sci. 2022 May;31(5):e4286. doi: 10.1002/pro.4286.
In Staphylococcus aureus, vancomycin-resistance-associated response regulator (VraR) is a part of the VraSR two-component system, which is responsible for activating a cell wall-stress stimulon in response to an antibiotic that inhibits cell wall formation. Two VraR-binding sites have been identified: R1 and R2 in the vraSR operon control region. However, the binding of VraR to a promoter DNA enhancing downstream gene expression remains unclear. VraR contains a conserved N-terminal receiver domain (VraR ) connected to a C-terminal DNA binding domain (VraR ) with a flexible linker. Here, we present the crystal structure of VraR alone and in complex with R1-DNA in 1.87- and 2.0-Å resolution, respectively. VraR consisting of four α-helices forms a dimer when interacting with R1-DNA. In the VraR -DNA complex structure, Mg ion is bound to Asp194. Biolayer interferometry experiments revealed that the addition of Mg to VraR enhanced its DNA binding affinity by eightfold. In addition, interpretation of NMR titrations between VraR with R1- and R2-DNA revealed the essential residues that might play a crucial role in interacting with DNA of the vraSR operon. The structural information could help in designing and screening potential therapeutics/inhibitors to deal with antibiotic-resistant S. aureus via targeting VraR.
在金黄色葡萄球菌中,万古霉素耐药相关反应调节剂(VraR)是 VraSR 双组分系统的一部分,该系统负责在抗生素抑制细胞壁形成时激活细胞壁应激刺激物。已经鉴定出两个 VraR 结合位点:vraSR 操纵子控制区的 R1 和 R2。然而,VraR 与增强下游基因表达的启动子 DNA 的结合仍然不清楚。VraR 包含一个保守的 N 端受体结构域(VraR),连接到带有柔性接头的 C 端 DNA 结合结构域(VraR)。在这里,我们分别以 1.87 和 2.0 Å 的分辨率呈现了单独的 VraR 和与 R1-DNA 复合物的晶体结构。当与 R1-DNA 相互作用时,由四个α螺旋组成的 VraR 形成二聚体。在 VraR-DNA 复合物结构中,Mg 离子与 Asp194 结合。Biolayer interferometry 实验表明,向 VraR 中添加 Mg 可使其 DNA 结合亲和力提高八倍。此外,对 VraR 与 R1-DNA 和 R2-DNA 之间 NMR 滴定的解释揭示了可能在与 vraSR 操纵子 DNA 相互作用中发挥关键作用的必需残基。这些结构信息可用于设计和筛选潜在的治疗剂/抑制剂,通过靶向 VraR 来应对耐抗生素的金黄色葡萄球菌。