title: Chemically synthesized galactosyl ficaprenyl diphosphate as an intermediate in the biosynthesis of the Salmonella O-antigenic polysaccharide.
abstract: The membrane fraction from a mutant of Salmonella anatum deficient in UDPgalactose-4-epimerase, utilized synthetic ficaprenyl alpha-D-galactosyl diphosphate as a substrate in the biosynthesis of the O-polysaccharide portion of lipopolysaccharide which has a mannosylrhamnosylgalactose repeating sequence. The galactosyl lipid was prepared by chemical synthesis from D-galactose and ficaprenol extracted from Ficus elastica. Membrane preparations catalyzed the transfer of rhamnose from TDP-rhamnose onto membrane-bound ficaprenyl galactosyl diphosphate forming rhamnosylgalactosyl ficaprenyl diphosphate; the reaction was dependent on the prior insertion of the synthetic glycosyl-lipid into the membrane, and was proportional to incubation time up to 4 min at 29 degrees C. When both TDP-rhamnose and GDP-mannose were added, the product formed was O-polysaccharide. These results indicate that the chemically synthesized ficaprenyl galactosyl diphosphate can be an active substrate for the in vitro synthesis of the Salmonella O-polysaccharide.
mesh_terms: D000942:Antigens, Bacterial / Q000096:biosynthesis*; D008563:Membrane Lipids / Q000378:metabolism*; D009154:Mutation; D019081:O Antigens; D011103:Polyisoprenyl Phosphate Monosaccharides / Q000138:chemical synthesis / Q000378:metabolism*; D011105:Polyisoprenyl Phosphate Sugars / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D012475:Salmonella / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D000942:Antigens, Bacterial; D008563:Membrane Lipids; D019081:O Antigens; D011103:Polyisoprenyl Phosphate Monosaccharides; D011105:Polyisoprenyl Phosphate Sugars; D011135:Polysaccharides, Bacterial; C038230:ficaprenyl galactosyl diphosphate