A Gene Cluster for Prenylated Naphthoquinone and Prenylated Phenazine Biosynthesis in Streptomyces cinnamonensis DSM 1042
✍ Scribed by Yvonne Haagen; Kerstin Glück; Katja Fay; Bernd Kammerer; Bertolt Gust; Lutz Heide
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 391 KB
- Volume
- 7
- Category
- Article
- ISSN
- 1439-4227
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✦ Synopsis
Abstract
Streptomyces cinnamonensis DSM 1042 produces two classes of secondary metabolites of mixed isoprenoid/nonisoprenoid origin: the polyketide–isoprenoid compound furanonaphthoquinone I (FNQ I) and several prenylated phenazines, predominantly endophenazine A. We now report the cloning and sequence analysis of a 55 kb gene cluster required for the biosynthesis of these compounds. Several inactivation experiments confirmed the involvement of this gene cluster in the biosynthesis of FNQ I and endophenazine A. The six identified genes for endophenazine biosynthesis showed close similarity to phenazine biosynthetic genes from Pseudomonas. Of the 28 open reading frames identified in the adjacent FNQ I cluster, 13 showed close similarity to genes contained in the cluster for furaquinocin—a structurally similar metabolite from another Streptomyces strain. These genes included a type III polyketide synthase sequence, a momA‐like monooxygenase gene, and two cloQ‐like prenyltransferase genes designated fnq26 and fnq28. Inactivation experiments confirmed the involvement of fnq26 in FNQ I biosynthesis, whereas no change in secondary‐metabolite formation was observed after fnq28 inactivation. The FNQ I cluster contains a contiguous group of five genes, which together encode all the enzymatic functions required for the recycling of S‐adenosylhomocysteine (SAH) to S‐adenosylmethionine (SAM). Two SAM‐dependent methyltransferases are encoded within the cluster. Inactivation experiments showed that fnq9 is responsible for the 7‐O‐methylation and fnq27 for the 6‐C‐methylation reaction in FNQ I biosynthesis.