Biosynthesis of the Escherichia coli K5 polysaccharide, a representative of group II capsular polysaccharides: polymerization in vitro and characterization of the product.
Biosynthesis of the capsular K5 polysaccharide of Escherichia coli, which has the structure 4)-beta GlcA-1,4-alpha GlcNAc-(1, was studied with membrane preparations from an E. coli K5 wild-type strain and from a recombinant K-12 strain expressing the K5 capsule. Polymerization occurs at the inner face of the cytoplasmic membrane without the participation of lipid-linked oligosaccharides. The serological K5 specificity of the in vitro product was determined with a K5-specific monoclonal antibody in an antigen-binding assay. The K5 polysaccharide, as obtained from the membranes after an in vitro incubation, has 2-keto-3-deoxyoctulosonic acid as the reducing sugar, which indicates that the polysaccharide grows by chain elongation at the nonreducing end.
Finke
A
A
Max-Planck-Institut für Immunobiologie, Freiburg, Federal Republic of Germany.
Bronner
D
D
Nikolaev
A V
AV
Jann
B
B
Jann
K
K
D000942:Antigens, Bacterial / Q000096:biosynthesis; D016667:Bacterial Capsules; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D005964:Glucosyltransferases / Q000378:metabolism; D007700:Kinetics; D046911:Macromolecular Substances; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis* / Q000737:chemistry / Q000502:physiology; D013400:Sugar Acids / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology
D000942:Antigens, Bacterial; D046911:Macromolecular Substances; D011135:Polysaccharides, Bacterial; D013400:Sugar Acids; C002532:2-keto-3-deoxyoctonate; D014415:Tunicamycin; C050673:capsular polysaccharide K5; D005964:Glucosyltransferases