Localization of the terminal steps of O-antigen synthesis in Salmonella typhimurium
Autor: | M. J. Osborn, B C McGrath |
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Rok vydání: | 1991 |
Předmět: |
Salmonella typhimurium
Lipopolysaccharide Stereochemistry Mutant Mannose Biology Tritium Microbiology chemistry.chemical_compound Biosynthesis Inner membrane Tetrasaccharide Polyisoprenyl Phosphate Sugars Molecular Biology chemistry.chemical_classification DNA ligase Polysaccharides Bacterial Galactose O Antigens Periplasmic space Kinetics chemistry Biochemistry Chromatography Gel Electrophoresis Polyacrylamide Gel Research Article |
Zdroj: | Journal of Bacteriology. 173:649-654 |
ISSN: | 1098-5530 0021-9193 |
Popis: | Previous immunoelectron microscopic studies have shown that both the final intermediate in O-antigen synthesis, undecaprenol-linked O polymer, and newly synthesized O-antigenic lipopolysaccharide are localized to the periplasmic face of the inner membrane (C. A. Mulford and M. J. Osborn, Proc. Natl. Acad. Sci. USA 80:1159-1163, 1983). In vivo pulse-chase experiments now provide further evidence that attachment of O antigen to core lipopolysaccharide, as well as polymerization of O-specific polysaccharide chains, takes place at the periplasmic face of the membrane. Mutants doubly conditional in lipopolysaccharide synthesis [kdsA(Ts) pmi] were constructed in which synthesis of core lipopolysaccharide and O antigen are temperature sensitive and mannose dependent, respectively. Periplasmic orientation of O antigen:core lipopolysaccharide ligase was established by experiments showing rapid chase of undecaprenol-linked O polymer, previously accumulated at 42 degrees C in the absence of core synthesis, into lipopolysaccharide following resumption of core formation at 30 degrees C. In addition, chase of the monomeric O-specific tetrasaccharide unit into lipopolysaccharide was found in similar experiments in an O-polymerase-negative [rfc kdsA(Ts) pmi] mutant, suggesting that polymerization of O chains also occurs at the external face of the inner membrane. |
Databáze: | OpenAIRE |
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