Expression of two structurally distinct D-galactan O antigens in the lipopolysaccharide of Klebsiella pneumoniae serotype O1.

摘要: The lipopolysaccharide (LPS) molecule is an important virulence determinant in Klebsiella pneumoniae. Studies on the serotype O1 LPS were initiated to determine basis for antigenic heterogeneity previously observed side chain polysaccharides and resolve apparent ambiguities reported polysaccharide structure. Detailed chemical analysis, involving methylation 1H- 13C-nuclear magnetic resonance studies, demonstrated that O-side of contained a mixture two structurally distinct D-galactan polymers. repeating unit structures these polymers identified as [----3)-beta-D-Galf-(1----3)-alpha-D-Galp-(1----] (D-galactan I) [----3)-alpha-D-Galp-(1----3)-beta-D-Galp-(1----] (D-Galactan II). D-Galactan I heterogeneous size detected throughout sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) profile LPS. In contrast, II was confined higher-molecular-weight region. D-galactans not influenced by simultaneous synthesis capsular K antigen. Apparently, neither constitutes common antigen widespread spp. determined immunochemical analysis. Examination LPSs mutants indicated expression can occur independently II. Transconjugants Escherichia coli K-12 strains carrying his region K. pneumoniae constructed chromosome mobilization with RP4::mini-Mu. transconjugants, O encoded his-linked rfb locus be I, suggesting genes involved are closely linked cluster. Images