title: Production of hybrid glycopeptide antibiotics in vitro and in Streptomyces toyocaensis.
abstract: BACKGROUND
  The glycopeptide antibiotics vancomycin and teicoplanin are currently the last line of defence against some microorganisms that are resistant to many drugs. The emergence of vancomycin-resistant and teicoplanin-resistant enterococci underscores the need for more potent antibiotics. The glycosylation patterns of glycopeptides and chemical modifications of the glycosyl moieties have been shown to greatly influence their antibiotic activity, and certain combinations have resulted in highly active new compounds. To explore further the production of more potent glycopeptide antibiotics, we assessed whether glycosyltransferases could be used to produce hybrid compounds that contain various combinations of sugars and peptide cores.
  
  
  RESULTS
  We cloned five glycosyltransferase genes from Amycolatopsis orientalis strains that produce vancomycin or a related glycopeptide, A82846. The gtfB and gtfE' genes from A. orientalis strains expressed in Escherichia coli produced glucosyltransferase activities that added glucose or xylose to the vancomycin heptapeptide. The GtfE' protein added glucose efficiently to two other heptapeptides related to teicoplanin to produce hybrid glycopeptide antibiotics. The cloned gtfE' gene, driven by the strong constitutive promoter ermEp*, was introduced into Streptomyces toyocaensis, which produces the antibiotic A47934, a heptapeptide related to teicoplanin; recombinant organisms produced glucosyl A47934, a hybrid glycopeptide antibiotic.
  
  
  CONCLUSIONS
  Cloned glycosyltransferases from glycopeptide antibiotic producers can be used to produce novel hybrid antibiotics, both in vitro and in vivo. Because similar enzymes have differing degrees of substrate specificity, it is advantageous to characterize the substrate specificity with enzymes expressed in E. coli prior to constructing recombinant actinomycetes for production.
authors.affiliation: Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN 46285, USA. PJS@Lilly.com
authors.forename: P J
authors.initials: PJ
authors.lastname: Solenberg
authors.forename: P
authors.initials: P
authors.lastname: Matsushima
authors.forename: D R
authors.initials: DR
authors.lastname: Stack
authors.forename: S C
authors.initials: SC
authors.lastname: Wilkie
authors.forename: R C
authors.initials: RC
authors.lastname: Thompson
authors.forename: R H
authors.initials: RH
authors.lastname: Baltz
mesh_terms: D039903:Actinobacteria / Q000201:enzymology / Q000235:genetics; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D003360:Cosmids / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015723:Gene Library; D005818:Genetic Engineering; D006020:Glycopeptides; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism; D006824:Hybridization, Genetic; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D013302:Streptomyces / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D006020:Glycopeptides; D016695:Glycosyltransferases