Kakinuma S, Takada Y, Ikeda H, Tanaka H, Omura S, Hopwood D A
School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan.
J Antibiot (Tokyo). 1991 Sep;44(9):995-1005. doi: 10.7164/antibiotics.44.995.
Large actI, III-homologous DNA fragments were isolated from genomic libraries of the strains that produce the benzoisochromanequinone antibiotics kalafungin and nanaomycin A methyl ester, Streptomyces tanashiensis strain Kala and Streptomyces sp. OM-173, respectively. These libraries were prepared in Escherichia coli JM108 by using a novel Streptomyces-E. coli bifunctional cosmid, pKU205, and screened with polyketide synthase genes (actI and III) for actinorhodin biosynthesis from Streptomyces coelicolor A3(2) as probes. The cloned DNA fragments (28 and 42 kb) were analyzed by hybridization with DNA containing actinorhodin biosynthetic genes (actI, II, III, IV, VA, VB, VI and VII). Both fragments hybridized with the actI, III, VA and VI regions, but not with the actII, IV, VB and VII regions. The cloned fragment of S. tanashiensis DNA was analyzed by complementation tests with kalafungin-nonproducing mutants. Seven genes (kalI approximately VII), which correspond to seven steps in kalafungin biosynthesis, were found to be located on a 14 kb continuous DNA fragment. Five of the genes were located on the regions homologous to the genes for actinorhodin biosynthesis, but the other two genes were not. Although kalafungin is an intermediate or shunt product in actinorhodin biosynthesis in S. coelicolor A3(2), the genes for kalafungin biosynthesis in S. tanashiensis are not identical with those in S. coelicolor A3(2).
从产生苯并异色满醌抗生素卡拉芬净和纳纳霉素A甲酯的菌株——塔纳链霉菌Kala菌株和链霉菌OM - 173的基因组文库中，分别分离出大片段的Ⅰ、Ⅲ同源DNA片段。这些文库是通过使用一种新型的链霉菌 - 大肠杆菌双功能黏粒pKU205在大肠杆菌JM108中构建的，并用来自天蓝色链霉菌A3(2)的放线紫红素生物合成的聚酮合酶基因（actI和III）作为探针进行筛选。通过与含有放线紫红素生物合成基因（actI、II、III、IV、VA、VB、VI和VII）的DNA杂交，对克隆的DNA片段（28和42 kb）进行了分析。两个片段均与actI、III、VA和VI区域杂交，但不与actII、IV、VB和VII区域杂交。通过与不产生卡拉芬净的突变体进行互补试验，对塔纳链霉菌DNA的克隆片段进行了分析。发现七个基因（kalI至VII），它们对应于卡拉芬净生物合成中的七个步骤，位于一个14 kb的连续DNA片段上。其中五个基因位于与放线紫红素生物合成基因同源的区域，但另外两个基因并非如此。尽管卡拉芬净是天蓝色链霉菌A3(2)中放线紫红素生物合成的中间产物或旁路产物，但塔纳链霉菌中卡拉芬净生物合成的基因与天蓝色链霉菌A3(2)中的基因并不相同。
