Caffrey P, Lynch S, Flood E, Finnan S, Oliynyk M
Department of Industrial Microbiology, University College Dublin, Ireland.
Chem Biol. 2001 Jul;8(7):713-23. doi: 10.1016/s1074-5521(01)00046-1.
The polyene macrolide amphotericin B is produced by Streptomyces nodosus ATCC14899. Amphotericin B is a potent antifungal antibiotic and has activity against some viruses, protozoans and prions. Treatment of systemic fungal infections with amphotericin B is complicated by its low water-solubility and side effects which include severe nephrotoxicity. Analogues with improved properties could be generated by manipulating amphotericin biosynthetic genes in S. nodosus.
A large polyketide synthase gene cluster was cloned from total cellular DNA of S. nodosus. Nucleotide sequence analysis of 113193 bp of this region revealed six large polyketide synthase genes as well as genes for two cytochrome P450 enzymes, two ABC transporter proteins, and genes involved in biosynthesis and attachment of mycosamine. Phage KC515-mediated gene disruption was used to show that this region is involved in amphotericin production.
The availability of these genes and the development of a method for gene disruption and replacement in S. nodosus should allow production of novel amphotericins. A panel of analogues could lead to identification of derivatives with increased solubility, improved biological activity and reduced toxicity.
多烯大环内酯两性霉素B由诺卡氏链霉菌ATCC14899产生。两性霉素B是一种强效抗真菌抗生素，对某些病毒、原生动物和朊病毒具有活性。用两性霉素B治疗全身性真菌感染会因其低水溶性和包括严重肾毒性在内的副作用而变得复杂。通过操纵诺卡氏链霉菌中的两性霉素生物合成基因可以产生具有改进特性的类似物。
从诺卡氏链霉菌的总细胞DNA中克隆了一个大的聚酮合酶基因簇。对该区域113193 bp的核苷酸序列分析揭示了六个大的聚酮合酶基因以及两个细胞色素P450酶、两个ABC转运蛋白的基因，以及参与霉菌胺生物合成和连接的基因。噬菌体KC515介导的基因破坏用于表明该区域参与两性霉素的产生。
这些基因的可用性以及诺卡氏链霉菌中基因破坏和替换方法的开发应该能够生产新型两性霉素。一组类似物可能会导致鉴定出具有更高溶解度、改进的生物活性和降低毒性的衍生物。
