tailieunhanh - Báo cáo Y học: Structural analysis of deacylated lipopolysaccharide of Escherichia coli strains 2513 (R4 core-type) and F653 (R3 core-type)

Lipopolysaccharide (LPS) ofEscherichia colistrain2513 (R4 core-type) yielded after alkaline deacylation one major oligosaccharide by high-performance anion-exchange chro-matography (HPAEC) which had a molecular mass of Da as determined by electrospray ionization mass spectrometry. This was in accordance with the calculated molecular mass of a tetraphosphorylated dodecasaccharide of the composition shown below. | Eur. J. Biochem. 269 5982-5991 2002 FEBS 2002 doi Structural analysis of deacylated lipopolysaccharide of Escherichia coli strains 2513 R4 core-type and F653 R3 core-type Sven Muller-Loennies Buko Lindner and Helmut Brade Borstel Research Center Center for Medicine and Biosciences Borstel Germany Lipopolysaccharide LPS of Escherichia coli strain 2513 R4 core-type yielded after alkaline deacylation one major oligosaccharide by high-performance anion-exchange chromatography HPAEC which had a molecular mass of We have also isolated the complete core-oligosaccha-rides of E. coli F653 LPS for which only preliminary data were available and investigated the deacylated LPS by Da as determined by electrospray ionization mass spectrometry. This was in accordance with the calculated molecular mass of a tetraphosphorylated dodecasaccharide ------------------------------------- of the composition shown below. NMR-analyses identified p the chemical structure as I _ _ i oc-D-Gal p-D-Gal L-oc-D-Hep aKdo a-D-GIcN Ậ2 4 í1 6 a-D-Glc-V3 a-D-Glc- L-a-D-Hepl3- L-c -D-Hep- - aKdo .p-D-GIcN Í p p p where L-a-D-Hep is L-glycero-a-D-manno-heptopyranose and Kdo is 3-deoxy-a-D-manno-oct-2-ulopyranosylonic acid and all hexoses are present as D-pyranoses. NMR and MS. The proposed structure determined previously by methylation analysis was confirmed and is shown below. a-D-GIcN p I t 1 a-D-GIc a-D-GIcN L-a-D-Hep ocKdo oc-D-GIcN ị ịl 6 a-D-GIc- a-D-Gal -D-Glc L-cc-D-Hepl3- L-cc-D-Hepi5 aKdo 5-D-GlcN In addition we have quantified the side-chain heptose substitution of the inner core with GlcpN 30 and confirmed that this sugar is only present when the phosphate at the second L D-Hepp residue is absent. Keywords Escherichia coli lipopolysaccharide R3 coretype R4 core-type structural analysis. Correspondence to S. Muller-Loennies Borstel Research Center Parkallee 22 23845 Borstel Germany. Fax 49 4537 188 419 .