Department of Pharmaceutical Sciences, Oregon State University, Corvallis, OR 97331-3507, United States.
J Nat Prod. 2013 May 24;76(5):939-46. doi: 10.1021/np400159a. Epub 2013 Apr 22.
The biosynthetic gene cluster for the pyralomicin antibiotics has been cloned and sequenced from Nonomuraea spiralis IMC A-0156. The 41 kb gene cluster contains 27 ORFs predicted to encode all of the functions for pyralomicin biosynthesis. This includes nonribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) required for the formation of the benzopyranopyrrole core unit, as well as a suite of tailoring enzymes (e.g., four halogenases, an O-methyltransferase, and an N-glycosyltransferase) necessary for further modifications of the core structure. The N-glycosyltransferase is predicted to transfer either glucose or a pseudosugar (cyclitol) to the aglycone. A gene cassette encoding C7-cyclitol biosynthetic enzymes was identified upstream of the benzopyranopyrrole-specific ORFs. Targeted disruption of the gene encoding the N-glycosyltransferase, prlH, abolished pyralomicin production, and recombinant expression of PrlA confirms the activity of this enzyme as a sugar phosphate cyclase involved in the formation of the C7-cyclitol moiety.
已从链霉菌(Nonomuraea spiralis)IMC A-0156 中克隆并测序了吡拉霉素抗生素的生物合成基因簇。该 41kb 的基因簇包含 27 个 ORF,预测编码吡拉霉素生物合成所需的所有功能。这包括形成苯并吡喃并吡咯核心单元所需的非核糖体肽合酶(NRPS)和聚酮合酶(PKS),以及一套修饰酶(例如,四个卤化酶、一个 O-甲基转移酶和一个 N-糖基转移酶),这些酶对于核心结构的进一步修饰是必要的。该 N-糖基转移酶预计将葡萄糖或假糖(环醇)转移到糖苷配基上。在苯并吡喃并吡咯特异性 ORF 的上游鉴定到了编码 C7-环醇生物合成酶的基因盒。靶向破坏编码 N-糖基转移酶(prlH)的基因导致吡拉霉素生产被废除,而重组表达 PrlA 证实了该酶作为参与 C7-环醇部分形成的糖磷酸环化酶的活性。