NMR-STUDY OF VIRENOSE AND DIHYDROHYDROXYSTREPTOSE ISOLATED FROM COXIELLA-BURNETII PHASE-I LIPOPOLYSACCHARIDE

A lipopolysaccharide (LPS I) isolated from Coxiella burnetii in virule nt phase I contains in its O-polysaccharide chain two unusual sugars, virenose (6-deoxy-3-C-methylgulose) and dihydrohydroxystreptose [3-C-( hydroxymethyl)lyxose]. The sugars were isolated from LPS I, after acid hydrolysis and removal of lipid A, by a combination of HPLC and prepa rative paper chromatography. Their enantiomeric forms and ring conform ations were established from optical rotation and NMR data. Two-dimens ional COSY, HSQC, and HMBC as well as one- and two-dimensional NOEs we re used to assign all proton and carbon signals in both monosaccharide s. Virenose was found to be the D-gulo enantiomer with the C-4(1), rin g conformation and dihydrohydroxystreptose was shown to be the L-lyxo enantiomer also with the C-4(1) conformation. The latter sugar was rep orted [S. Schramek, J. Radziejewska-Lebrecht, and H. Mayer, fur. J. Bi ochem., 148 (1985) 455-461] to be present in LPS I in a furanose form, and it apl!ears that a furanose to pyranose tautomerization took plac e in the course of the isolation procedure. (C) 1998 Elsevier Science Ltd. All rights reserved.