Showing papers by "Jolanta Kumirska published in 2005"

Repeating unit structure of Enterobacter sakazakii ZORB A 741 O-polysaccharide

Abstract: The O-specific polysaccharide from Enterobacter sakazakii cell was isolated and structurally characterized. Lipopolysaccharide (LPS) was obtained from cell mass by hot phenol-water extraction procedure. Mild acid hydrolysis followed by gel filtration provided pure O-antigen (OPS). Two-stage sugar analysis detected tyvelose, rhamnose and galactose in the molar ratio of 1:1:2, and their linkages were established by means of methylation analysis. Sugar configurations, D or L, were determined by gas-liquid chromatography on an achiral liquid phase for (S)-(+)-2-butyl glycosides. D configuration was determined for galactose and 3,6-dideoxy-mannose (tyvelose), but L for rhamnose. Repeating unit structure was deduced by analysis of 1 H and 1 3 C NMR spectra. 1 H and 1 3 C NMR resonances have been assigned by homonuclear (COSY, TOCSY) and heteronuclear (HSQC, HMBC) correlations spectra. Anomeric configurations were determined from anomeric proton chemical shifts and 3 J H 1 - H 2 and J C - H coupling constants. Sugar sequences were established from comparisons of specific carbon chemical shifts with those in literature, two-dimensional nuclear Overhauser effect spectroscopy (NOESY), and heteronuclear multiple-bond correlation experiments (HMBC). The repeating unit structure of Enterobacter sakazakii was found to be as: α-Tyvp ↓ 2 →3)-a-L-Rhap-(1→3)-α-D-Galp-(1→3)-α-D-Galp-(1→ ∩ 6 O-Ac.