Shawky Riham M, Puk Oliver, Wietzorrek Andreas, Pelzer Stefan, Takano Eriko, Wohlleben Wolfgang, Stegmann Efthimia
Eberhard-Karls-Universität Tübingen, Mikrobiologisches Institut, Lehrstuhl für Mikrobiologie/Biotechnologie, Tübingen, Germany.
J Mol Microbiol Biotechnol. 2007;13(1-3):76-88. doi: 10.1159/000103599.
Balhimycin, produced by the actinomycete Amycolatopsis balhimycina DSM5908, is a glycopeptide antibiotic highly similar to vancomycin, the antibiotic of 'last resort' used for the treatment of resistant Gram-positive pathogenic bacteria. Partial sequence of the balhimycin biosynthesis gene cluster was previously reported. In this work, cosmids which overlap the region of the characterized gene cluster were isolated and sequenced. At the 'left' end of the cluster, genes were identified which are involved in balhimycin biosynthesis, transport, resistance and regulation. The 'right' end border is defined by a putative 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (dahp) gene. The proximate gene is similar to a type I polyketide synthase gene of the rifamycin producer Amycolatopsis mediterranei indicating that another biosynthesis gene cluster might be located directly next to the balhimycin gene cluster. The newly identified StrR-like pathway-specific regulator, Bbr, was characterized to be a DNA-binding protein and may have a role in balhimycin biosynthesis. Purified N-terminally His-tagged Bbr shows specific DNA-binding to five promoter regions within the gene cluster. By in silico analysis and by comparison of the DNA sequences binding Bbr, conserved inverted repeat sequences for the Bbr-binding site are proposed. The putative Bbr consensus sequence differs from that published for StrR.
由放线菌Balhimycina DSM5908产生的巴利霉素是一种糖肽抗生素,与用于治疗耐药革兰氏阳性病原菌的“最后手段”抗生素万古霉素高度相似。先前已报道了巴利霉素生物合成基因簇的部分序列。在这项工作中,分离并测序了与已鉴定基因簇区域重叠的黏粒。在该基因簇的“左端”,鉴定出了参与巴利霉素生物合成、转运、抗性和调控的基因。“右端”边界由一个假定的3-脱氧-D-阿拉伯庚酮糖酸-7-磷酸合酶(dahp)基因界定。紧邻的基因类似于利福霉素产生菌地中海拟无枝酸菌的I型聚酮合酶基因,这表明另一个生物合成基因簇可能直接位于巴利霉素基因簇旁边。新鉴定的StrR样途径特异性调节因子Bbr被表征为一种DNA结合蛋白,可能在巴利霉素生物合成中起作用。纯化的N端带有His标签的Bbr显示出与基因簇内五个启动子区域的特异性DNA结合。通过计算机分析和对结合Bbr的DNA序列的比较,提出了Bbr结合位点的保守反向重复序列。假定的Bbr共有序列与已发表的StrR的共有序列不同。