title: Rationally designed glycosylated premithramycins: hybrid aromatic polyketides using genes from three different biosynthetic pathways.
abstract: Heterologous expression of the urdGT2 gene from the urdamycin producer Streptomyces fradiae Tü2717, which encodes a C-glycosyltransferase, into mutants of the mithramycin producer Streptomyces argillaceus, in which either one or all glycosyltransferases were inactivated, yielded four novel C-glycosylated premithramycin-type molecules. Structure elucidation revealed these to be 9-C-olivosylpremithramycinone, 9-C-mycarosylpremithramycinone, and their respective 4-O-demethyl analogues. In another experiment, both the urdGT2 gene from S. fradiae and the lanGT1 gene from S. cyanogenus, were coexpressed into a S. argillaceus mutant lacking the MtmGIV glycosyltransferase. This experiment, in which genes from three different organisms were combined, resulted in the production of 9-C-(olivo-1-4-olivosyl)premithramycinone. These results prove the unique substrate flexibility of the C-glycosyltransferase UrdGT2, which tolerates not only a variety of sugar-donor substrates, but also various acceptor substrates. The five new hybrid products also represent the first compounds, in which sugars were attached to a position that is normally unglycosylated. The successful combination of two glycosyltransferases in the latter experiment proves that the design of saccharide side chains by combinatorial biosynthetic methods is possible.
authors.affiliation: Albert-Ludwigs-Universität Freiburg im Breisgau, Pharmazeutische Biologie, Stefan-Meier Strasse 19, 79104 Freiburg, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Trefzer
authors.forename: Gloria
authors.initials: G
authors.lastname: Blanco
authors.forename: Lily
authors.initials: L
authors.lastname: Remsing
authors.forename: Eva
authors.initials: E
authors.lastname: Künzel
authors.forename: Uwe
authors.initials: U
authors.lastname: Rix
authors.forename: Fredilyn
authors.initials: F
authors.lastname: Lipata
authors.forename: Alfredo F
authors.initials: AF
authors.lastname: Braña
authors.forename: Carmen
authors.initials: C
authors.lastname: Méndez
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rohr
authors.forename: Andreas
authors.initials: A
authors.lastname: Bechthold
authors.forename: José A
authors.initials: JA
authors.lastname: Salas
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000096:biosynthesis*; D006027:Glycosides / Q000096:biosynthesis*; D016695:Glycosyltransferases / Q000235:genetics* / Q000378:metabolism; D008926:Plicamycin / Q000031:analogs & derivatives* / Q000096:biosynthesis; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics*
chemical_list: D000903:Antibiotics, Antineoplastic; D006027:Glycosides; D016695:Glycosyltransferases; D008926:Plicamycin