Regulation of the furA and catC operon, encoding a ferric uptake regulator homologue and catalase-peroxidase, respectively, in Streptomyces coelicolor A3(2)
Regulation of the furA and catC operon, encoding a ferric uptake regulator homologue and catalase-peroxidase, respectively, in Streptomyces coelicolor A3(2)
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DOI：
10.1128/jb.182.13.3767-3774.2000
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发表时间：
2000-07-01
影响因子：
3.2
通讯作者：
Roe, JH
中科院分区：
文献类型：
--
作者：
Hahn, JS;Oh, SY;Roe, JH
通过与大肠杆菌中catC基因序列的同源性分析，分离出了链霉菌过氧化氢酶-过氧化物酶编码基因。在catC基因的上游，发现了一个开放阅读框（furA），编码铁摄取调节因子（Fur）的同源物。S1定位分析表明furA基因与catC基因共转录。furA- catc mRNA的转录起始位点定位于furA基因的翻译起始密码子ATG。假定的启动子包含与S. coelicolor的主要sigma因子（HrdB）识别的-10和-35个相似的元素。在液体培养中，转录本在指数后期产生最多，在固定阶段产生较少。mRNA数量的变化与CatC蛋白和酶活性的变化一致。当将furA基因通过多拷贝质粒导入S. lividans时，生长后期catC转录本和蛋白产物的增加受到抑制，这表明furA可能是furA-catC操纵子的负调控因子。FurA蛋白从转录起始位点的-59到-39个核苷酸之间到达其自身的启动子区域。在还原条件下，当有Ni2+、Mn2+、Zn2+、Fe2+等金属存在时，FurA的结合亲和力增强。在生长培养基中添加这些金属会降低CatC蛋白的产量，这与FurA作为金属依赖性抑制因子的作用一致。
We isolated the catC gene, encoding catalase-peroxidase in Streptomyces coelicolor, using sequence homology with the katG gene from Escherichia coli. Upstream of the catC gene, an open reading frame (furA) encoding a homologue of ferric uptake regulator (Fur) was identified. S1 mapping analysis indicated that the furA gene was cotranscribed with the catC gene. The transcriptional start site of the furA-catC mRNA was mapped to the translation start codon ATG of the furA gene. The putative promoter contains consensus -10 and -35 elements similar to those recognized by sigma(HrdB), th, major sigma factor of S. coelicolor. The transcripts were produced maximally at late-exponential phase and decreased at the stationary phase in liquid culture. The change in the amount of mRNA was consistent with that of CatC protein and enzyme activity. When the furA gene was introduced into S. lividans on a multicopy plasmid, the increased production of catC transcripts and protein product at late growth phase was inhibited, implying a role for FurA as the negative regulator of the furA-catC operon. FurA protein hound to its own promoter region between -59 and -39 nucleotides from the transcription start site. The binding affinity of FurA increased under reducing conditions and in the presence of metals such as Ni2+, Mn2+, Zn2+, or Fe2+. Addition of these metals to the growth medium decreased the production of CatC protein, consistent with the role of FurA as a metal-dependent repressor.