Piecq M, Dehottay P, Biot A, Dusart J
Centre d'Ingénierie des Protéines, Université de Liège, Belgium.
DNA Seq. 1994;4(4):219-29. doi: 10.3109/10425179409020845.
The actinomycete Kibdelosporangium aridum naturally produces ardacin, a new glycopeptide antibiotic, the biosynthetic pathway of which should involve the participation of a polyketide synthase (PKS). A K. aridum 2.9 kb BamHI genomic fragment homologous to actI (a locus of the PKS cluster catalyzing polyketide chain assembly for actinorhodin biosynthesis in Streptomyces coelicolor) was isolated by shotgun cloning. This DNA fragment, called ardI, was sequenced and the deduced protein products were compared with those of other polyketide synthase genes, revealing similarities ranging from 50 to 80%. ardI was further used to probe a cosmid library of the K. aridum genome. Three hybridizing cosmids were obtained which contain overlapping inserts, together covering a 50 kb region, and including, 15 kb away from ardI, a fragment homologous to actIII, which codes for the ketoreductase of the actinorhodin PKS of S. coelicolor. All these findings indicate that at least part of a polyketide biosynthetic gene cluster has been isolated from the genome of the ardacin producer K. aridum.
放线菌干旱栖热放线菌天然产生阿地辛，一种新的糖肽抗生素，其生物合成途径应涉及聚酮合酶（PKS）的参与。通过鸟枪法克隆分离出与actI（在天蓝色链霉菌中催化放线紫红素生物合成的聚酮链组装的PKS簇的一个位点）同源的干旱栖热放线菌2.9 kb BamHI基因组片段。这个称为ardI的DNA片段被测序，并将推导的蛋白质产物与其他聚酮合酶基因的产物进行比较，发现相似性范围为50%至80%。ardI进一步用于探测干旱栖热放线菌基因组的粘粒文库。获得了三个杂交粘粒，它们包含重叠的插入片段，一起覆盖了一个50 kb的区域，并且在距离ardI 15 kb处包括一个与actIII同源的片段，actIII编码天蓝色链霉菌放线紫红素PKS的酮还原酶。所有这些发现表明，已从阿地辛产生菌干旱栖热放线菌的基因组中分离出至少一部分聚酮生物合成基因簇。
