Lee Mi-Yeon, Myeong Ji Seon, Park Hyun-Joo, Han Kyuboem, Kim Eung-Soo
Department of Biotechnology, Inha University, 402-751, Incheon, Korea.
J Ind Microbiol Biotechnol. 2006 Feb;33(2):84-7. doi: 10.1007/s10295-005-0018-7. Epub 2005 Aug 12.
The polyene antibiotics, a category that includes nystatin, pimaricin, amphotericin, and candicidin, comprise a family of very promising antifungal polyketide compounds and are typically produced by soil actinomycetes. The biosynthetic gene clusters for these polyenes have been previously investigated, revealing the presence of highly similar cytochrome P450 hydroxylase (CYP) genes. Using polyene CYP-specific PCR screening with several actinomycete genomic DNAs, Pseudonocardia autotrophica was determined to contain a unique polyene-specific CYP gene. Genomic DNA library screening using the polyene-specific CYP gene probe identified a positive cosmid clone, which contained a DNA fragment of approximately 34.5 kb. The complete sequencing of this DNA fragment revealed a total of seven complete and two incomplete open reading frames, which were found to be highly similar, but still unique, when compared to previously known polyene biosynthetic genes. These results suggest that the polyene-specific screening approach may constitute an efficient method for the isolation of potentially valuable cryptic polyene biosynthetic gene clusters from various rare actinomycetes.
多烯类抗生素包括制霉菌素、匹马霉素、两性霉素和杀假丝菌素，是一类非常有前景的抗真菌聚酮化合物，通常由土壤放线菌产生。此前已对这些多烯类抗生素的生物合成基因簇进行了研究，发现存在高度相似的细胞色素P450羟化酶（CYP）基因。通过对几种放线菌基因组DNA进行多烯CYP特异性PCR筛选，确定自养假诺卡氏菌含有一个独特的多烯特异性CYP基因。使用多烯特异性CYP基因探针进行基因组DNA文库筛选，鉴定出一个阳性粘粒克隆，该克隆包含一个约34.5 kb的DNA片段。对该DNA片段进行全序列测定，共发现7个完整的和2个不完整的开放阅读框，与先前已知的多烯生物合成基因相比，这些开放阅读框高度相似，但仍具有独特性。这些结果表明，多烯特异性筛选方法可能是从各种稀有放线菌中分离潜在有价值的隐秘多烯生物合成基因簇的有效方法。
