Zong Gongli, Cao Guangxiang, Fu Jiafang, Zhang Peipei, Chen Xi, Yan Wenxiu, Xin Lulu, Wang Zhongxue, Xu Yan, Zhang Rongzhen
Key Laboratory of Industrial Biotechnology of Ministry of Education & School of Biotechnology, Jiangnan University , Wuxi, China.
Biomedical Sciences College & Shandong Medicinal Biotechnology Centre, Shandong First Medical University & Shandong Academy of Medical Sciences , Ji'nan, China.
Microbiol Spectr. 2023 Sep 11;11(5):e0087923. doi: 10.1128/spectrum.00879-23.
The mechanism of regulation of natamycin biosynthesis by Streptomyces in response to oxidative stress is unclear. Here, we first show cholesterol oxidase SgnE, which catalyzes the formation of HO from sterols, triggered a series of redox-dependent interactions to stimulate natamycin production in . In response to reactive oxygen species, residues Cys212 and Cys221 of the HO-sensing consensus sequence of OxyR were oxidized, resulting in conformational changes in the protein: OxyR extended its DNA-binding domain to interact with four motifs of promoter p . This acted as a redox-dependent switch to turn on/off gene transcription of , which encodes a cluster-situated regulator, by controlling the affinity between OxyR and p , thus regulating the expression of 12 genes in the natamycin biosynthesis gene cluster. OxyR cooperates with SgnR, another cluster-situated regulator and an upstream regulatory factor of SgnM, synergistically modulated natamycin biosynthesis by masking/unmasking the -35 region of p depending on the redox state of OxyR in response to the intracellular HO concentration. IMPORTANCE Cholesterol oxidase SgnE is an indispensable factor, with an unclear mechanism, for natamycin biosynthesis in . Oxidative stress has been attributed to the natamycin biosynthesis. Here, we show that SgnE catalyzes the formation of HO from sterols and triggers a series of redox-dependent interactions to stimulate natamycin production in . OxyR, which cooperates with SgnR, acted as a redox-dependent switch to turn on/off gene transcription of , which encodes a cluster-situated regulator, by masking/unmasking its -35 region, to control the natamycin biosynthesis gene cluster. This work provides a novel perspective on the crosstalk between intracellular ROS homeostasis and natamycin biosynthesis. Application of these findings will improve antibiotic yields via control of the intracellular redox pressure in .
链霉菌响应氧化应激调控纳他霉素生物合成的机制尚不清楚。在此，我们首次表明，催化甾醇形成H₂O₂的胆固醇氧化酶SgnE引发了一系列依赖氧化还原的相互作用，以刺激纳他霉素的产生。响应活性氧，OxyR的H₂O₂感应共有序列中的Cys212和Cys221残基被氧化，导致蛋白质构象发生变化：OxyR扩展其DNA结合结构域，与启动子p的四个基序相互作用。这作为一个依赖氧化还原的开关，通过控制OxyR与p的亲和力来开启/关闭编码簇定位调节因子的基因转录，从而调节纳他霉素生物合成基因簇中12个基因的表达。OxyR与另一个簇定位调节因子SgnR以及SgnM的上游调节因子协同作用，根据细胞内H₂O₂浓度响应OxyR的氧化还原状态，通过掩盖/暴露p的-35区域，协同调节纳他霉素的生物合成。重要性胆固醇氧化酶SgnE是纳他霉素生物合成中不可或缺的因素，其机制尚不清楚。氧化应激被认为与纳他霉素生物合成有关。在此，我们表明SgnE催化甾醇形成H₂O₂，并引发一系列依赖氧化还原的相互作用，以刺激纳他霉素的产生。与SgnR协同作用的OxyR作为一个依赖氧化还原的开关，通过掩盖/暴露其-35区域来开启/关闭编码簇定位调节因子的基因转录，以控制纳他霉素生物合成基因簇。这项工作为细胞内活性氧稳态与纳他霉素生物合成之间的相互作用提供了新的视角。这些发现的应用将通过控制细胞内氧化还原压力来提高抗生素产量。
