title: Biosynthetic code for divergolide assembly in a bacterial mangrove endophyte.
abstract: Divergolides are structurally diverse ansamycins produced by a bacterial endophyte (Streptomyces sp.) of the mangrove tree Bruguiera gymnorrhiza. By genomic analyses a gene locus coding for the divergolide pathway was detected. The div gene cluster encodes genes for the biosynthesis of 3-amino-5-hydroxybenzoate and the rare extender units ethylmalonyl-CoA and isobutylmalonyl-CoA, polyketide assembly by a modular type I polyketide synthase (PKS), and enzymes involved in tailoring reactions, such as a Baeyer-Villiger oxygenase. A detailed PKS domain analysis confirmed the stereochemical integrity of the divergolides and provided valuable new insights into the formation of the diverse aromatic chromophores. The bioinformatic analyses and the isolation and full structural elucidation of four new divergolide congeners led to a revised biosynthetic model that illustrates the formation of four different types of ansamycin chromophores from a single polyketide precursor.
authors.affiliation: Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstrasse 11a, 07745 Jena (Germany).
authors.forename: Zhongli
authors.initials: Z
authors.lastname: Xu
authors.forename: Martin
authors.initials: M
authors.lastname: Baunach
authors.forename: Ling
authors.initials: L
authors.lastname: Ding
authors.forename: Huiyun
authors.initials: H
authors.lastname: Peng
authors.forename: Jakob
authors.initials: J
authors.lastname: Franke
authors.forename: Christian
authors.initials: C
authors.lastname: Hertweck
mesh_terms: D018942:Macrolides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008968:Molecular Conformation; D043982:Rhizophoraceae / Q000382:microbiology*; D013302:Streptomyces / Q000737:chemistry / Q000378:metabolism*
chemical_list: D018942:Macrolides
keywords: ansamycins; biosynthesis; divergolides; modular polyketide synthases; polyketides