The transcription factor PdhR has been recognized as the master regulator of the pyruvate catabolism pathway in Escherichia coli , including both NAD-linked oxidative decarboxylation of pyruvate to acetyl-CoA by PDHc (pyruvate dehydrogenase complex) and respiratory electron transport of NADH to oxygen by Ndh-CyoABCD enzymes. To identify the whole set of regulatory targets under the control of pyruvate-sensing PdhR, we performed genomic SELEX (gSELEX) screening in vitro. A total of 35 PdhR-binding sites were identified along the E. coli K-12 genome, including previously identified targets. Possible involvement of PdhR in regulation of the newly identified target genes was analysed in detail by gel shift assay, RT-qPCR and Northern blot analysis. The results indicated the participation of PdhR in positive regulation of fatty acid degradation genes and negative regulation of cell mobility genes. In fact, GC analysis indicated an increase in free fatty acids in the mutant lacking PdhR. We propose that PdhR is a bifunctional global regulator for control of a total of 16–23 targets, including not only the genes involved in central carbon metabolism but also some genes for the surrounding pyruvate-sensing cellular pathways such as fatty acid degradation and flagella formation. The activity of PdhR is controlled by pyruvate, the key node between a wide variety of metabolic pathways, including generation of metabolic energy and cell building blocks.

中文翻译：

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丙酮酸感应 PdhR 在大肠杆菌 K-12 基因组转录调控中的扩展作用：脂肪酸分解代谢和细胞运动

转录因子 PdhR 已被认为是大肠杆菌中丙酮酸分解代谢途径的主要调节因子，包括通过 PDHc（丙酮酸脱氢酶复合物）将丙酮酸与 NAD 连接的氧化脱羧为乙酰辅酶 A 和通过 Ndh 将 NADH 呼吸电子传递到氧气。 -CyoABCD 酶。为了确定丙酮酸感应 PdhR 控制下的整套监管目标，我们在体外进行了基因组 SELEX (gSELEX) 筛选。沿着大肠杆菌共鉴定了 35 个 PdhR 结合位点 K-12 基因组，包括先前确定的目标。通过凝胶位移测定、RT-qPCR 和 Northern 印迹分析详细分析了 PdhR 可能参与调控新鉴定的靶基因。结果表明PdhR参与脂肪酸降解基因的正调控和细胞运动基因的负调控。事实上，GC 分析表明缺乏 PdhR 的突变体中游离脂肪酸增加。我们提出 PdhR 是一个双功能全局调节器，用于控制总共 16-23 个目标，不仅包括参与中央碳代谢的基因，还包括一些用于周围丙酮酸感应细胞途径的基因，如脂肪酸降解和鞭毛形成. PdhR 的活性受丙酮酸控制，丙酮酸是多种代谢途径之间的关键节点，