title: Three enzymes involved in the N-methylation and incorporation of the pradimicin sugar moieties.
abstract: Pradimicins are antifungal and antiviral natural products from Actinomadura hibisca P157-2. The sugar moieties play a critical role in the biological activities of these compounds. There are two glycosyltransferase genes in the pradimicin biosynthetic gene cluster, pdmS and pdmQ, which are putatively responsible for the introduction of the sugar moieties during pradimicin biosynthesis. In this study, we disrupted these two genes using a double crossover approach. Disruption of pdmS led to the production of pradimicinone I, the aglycon of pradimicin A, which confirmed that PdmS is the O-glycosyltransferase responsible for the first glycosylation step and attaching the 4',6'-dideoxy-4'-amino-d-galactose or 4',6'-dideoxy-4'-methylamino-d-galactose moiety to the 5-OH. Disruption of pdmQ resulted in the production of pradimicin B, indicating that this enzyme is the second glycosyltransferase that introduces the d-xylose moiety to the 3'-OH of the first sugar moiety. Insertion of an integrative plasmid before pdmO might have interfered with the dedicated promoter, yielding a mutant that produces pradimicin C as the major metabolite, which suggested that PdmO is the enzyme that specifically methylates the 4'-NH2 of the 4',6'-dideoxy-4'-amino-d-galactose moiety. Functional characterization of these sugar-decorating and -incorporating enzymes thus facilitates the understanding of the pradimicin biosynthetic pathway.
authors: Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, UT 84322, United States.
authors: Kandy L
authors: KL
authors: Napan
authors: Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, UT 84322, United States.
authors: Shuwei
authors: S
authors: Zhang
authors: Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, United States.
authors: Thomas
authors: T
authors: Anderson
authors: Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, United States.
authors: Jon Y
authors: JY
authors: Takemoto
authors: Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, UT 84322, United States. Electronic address: jixun.zhan@usu.edu.
authors: Jixun
authors: J
authors: Zhan
mesh_terms: D039903:Actinobacteria / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism; D018943:Anthracyclines / Q000737:chemistry / Q000378:metabolism*; D006031:Glycosylation; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism; D008745:Methylation; D009154:Mutation; D011995:Recombination, Genetic; D000095643:Pradimicins and Benanomicins
chemical_list: D018943:Anthracyclines; D016695:Glycosyltransferases; C056806:benanomicin B; D000095643:Pradimicins and Benanomicins; C058036:pradimicin A; C058037:pradimicin B
keywords: Gene disruption; Glycosyltransferase; Methyltransferase; Polyketide; Pradimicin A