Grimm A, Madduri K, Ali A, Hutchinson C R
Department of Genetics, University of Wisconsin, Madison 53706.
Gene. 1994 Dec 30;151(1-2):1-10. doi: 10.1016/0378-1119(94)90625-4.
The dps genes of Streptomyces peucetius, encoding daunorubicin (DNR)-doxorubicin (DXR) polyketide synthase (PKS), are largely within an 8.7-kb region of DNA that has been characterized by Southern analysis, and gene sequencing, mutagenesis and expression experiments. This region contains nine ORFs, many of whose predicted products are homologous to known PKS enzymes. Surprisingly, the gene encoding the DXR PKS acyl carrier protein is not in this region, but is located about 10 kb distant from the position it usually occupies in other gene clusters encoding type-II PKS. An in-frame deletion in the dpsB gene, encoding a putative subunit of the DXR PKS, resulted in loss of production of DXR and the known intermediates of its biosynthetic pathway, confirming that this gene and, by implication, the adjacent dps genes are required for DXR biosynthesis. This was verified by expression of the dps genes in the heterologous host, Streptomyces lividans, which resulted in the production of aklanonic acid, an early intermediate of DXR biosynthesis.
产柔毛链霉菌（Streptomyces peucetius）的dps基因编码柔红霉素（DNR）-阿霉素（DXR）聚酮合酶（PKS），主要位于一段8.7 kb的DNA区域内，该区域已通过Southern分析、基因测序、诱变和表达实验进行了表征。该区域包含9个开放阅读框（ORF），其中许多预测产物与已知的PKS酶同源。令人惊讶的是，编码DXR PKS酰基载体蛋白的基因并不在该区域，而是位于距离其在其他编码II型PKS的基因簇中通常占据位置约10 kb处。编码DXR PKS假定亚基的dpsB基因中的框内缺失导致DXR及其生物合成途径的已知中间体的产生丧失，证实该基因以及相关的dps基因是DXR生物合成所必需的。这通过在异源宿主天蓝色链霉菌（Streptomyces lividans）中表达dps基因得到验证，该表达导致了阿克拉诺酸的产生，阿克拉诺酸是DXR生物合成的早期中间体。
