In order to adapt in host tissues, microbial pathogens regulate their gene expression through an array of transcription factors. Here, we have functionally characterized Rv0792c, a GntR homolog from M. tuberculosis. In comparison to the parental strain, ΔRv0792c mutant strain of M. tuberculosis was compromised for survival upon exposure to oxidative stress, cell wall agents and infection in guinea pigs. RNA-seq analysis revealed that Rv0792c regulates the expression of genes that are involved in stress adaptation and virulence of M. tuberculosis. Solution small angle X-ray scattering (SAXS) data steered model building confirmed that the C-terminal region plays a pivotal role in dimer formation. Systematic evolution of ligands by exponential enrichment resulted in identification of ssDNA aptamers that can be used as a tool to identify small molecule inhibitors targeting Rv0792c. Using SELEX and SAXS data based modelling, we identified residues essential for the DNA binding activity of Rv0792c and I-OMe-Tyrphostin as an inhibitor of Rv0792c aptamer binding activity. Taken together, we provide a detailed shape-function characterization of GntR family of transcription factors from M. tuberculosis. To the best of our knowledge, this is the first study that has resulted in the identification of small molecule inhibitors against GntR family of transcription factors from bacterial pathogens.

中文翻译：

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结核分枝杆菌 Rv0792c 的结构和功能表征：鉴定针对 GntR 蛋白的小分子抑制剂

为了适应宿主组织，微生物病原体通过一系列转录因子调节其基因表达。在这里，我们在功能上表征了 Rv0792c，一种来自结核分枝杆菌的 GntR 同源物。与亲本菌株相比，结核分枝杆菌的ΔRv0792c 突变菌株在暴露于氧化应激、细胞壁试剂和豚鼠感染后的存活率受到影响。RNA-seq 分析显示，Rv0792c 调节参与压力适应和结核分枝杆菌毒力的基因的表达. 解决方案小角 X 射线散射 (SAXS) 数据引导模型构建证实 C 端区域在二聚体形成中起关键作用。通过指数富集对配体的系统进化导致了 ssDNA 适配体的鉴定，该适配体可用作鉴定靶向 Rv0792c 的小分子抑制剂的工具。使用基于 SELEX 和 SAXS 数据的建模，我们确定了 Rv0792c 和 I-OMe-Tyrphostin 的 DNA 结合活性所必需的残基，作为 Rv0792c 适体结合活性的抑制剂。总之，我们提供了结核分枝杆菌GntR 转录因子家族的详细形状功能表征. 据我们所知，这是第一项导致从细菌病原体中鉴定出针对 GntR 转录因子家族的小分子抑制剂的研究。