Protection against oxidative stress is a vital defense mechanism for Mycobacterium tuberculosis within the host. However, few transcription factors that control bacterial antioxidant defense are known. Here, we present evidence that SdrR, encoded by the MSMEG_5712 (Ms5712) gene, functions as an oxidative stress response regulator in Mycobacterium smegmatis. SdrR recognizes an 11-bp motif sequence in the operon's upstream regulatory region and negatively regulates the expression of short-chain dehydrogenases/reductases (SDR). Overexpressing sdrR inhibited SDR expression, which rendered the strain oxidative more stress-sensitive. Conversely, sdrR knockout alleviates SDR repression, which increases its oxidative stress tolerance. Thus, SdrR responds to oxidative stress by negatively regulating sdr expression. Therefore, this study elucidated an underlying regulatory mechanism behind mycobacterial oxidative stress adaptation.

中文翻译：

---

SdrR 是一种 LysR 型调节剂，可响应分枝杆菌抗氧化防御

防止氧化应激是宿主体内结核分枝杆菌的重要防御机制。然而，控制细菌抗氧化防御的转录因子却鲜为人知。在这里，我们提供的证据表明，由 MSMEG_5712 (Ms5712) 基因编码的 SdrR 在耻垢分枝杆菌中充当氧化应激反应调节剂。SdrR 识别操纵子上游调节区的 11 bp 基序序列，并负向调节短链脱氢酶/还原酶 (SDR) 的表达。过度表达 sdrR 会抑制 SDR 表达，从而使菌株对氧化应激更加敏感。相反，sdrR 敲除减轻了 SDR 抑制，从而提高了其氧化应激耐受性。因此，SdrR 通过负向调节 sdr 表达来响应氧化应激。因此，这项研究阐明了分枝杆菌氧化应激适应背后的潜在调节机制。