Glycobiology Advance Access originally published online on August 8, 2009
Glycobiology 2009 19(12):1436-1445; doi:10.1093/glycob/cwp117
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Published by Oxford University Press 2009.
Phosphoethanolamine is located at the 6-position and not at the 7-position of the distal heptose residue in the lipopolysaccharide from Neisseria meningitidis
2 Institute for Biological Sciences, National Research Council, Ottawa, ON, K1A 0R6, Canada
3 Weatherall Institute for Molecular Medicine, University of Oxford, Headington, Oxon, OX3 9DU, UK
1 To whom correspondence should be addressed: Tel: +1-613-991-6172; Fax: +1-613-952-9092; e-mail: Andrew.Cox{at}nrc-cnrc.gc.ca
Received on June 8, 2009; revised on July 15, 2009; accepted on August 3, 2009
Previous studies on LPS from Neisseria meningitidis strains M992B, the immunotype L6 strain, NMB, the type strain, a candidate LPS vaccine strain 6275z, and an extensively used clinical strain M986 had suggested that the location of the phosphoethanolamine (PEtn) residue was the 7-position of the distal heptose residue (HepII) of the inner-core oligosaccharide (OS). In all cases, this was only established by chemical methods, methylation linkage analyses. In this study, we have used standard NMR techniques to unequivocally show that the PEtn residue is actually located at the 6-position and not at the 7-position of the HepII residue in all of these strains. The 6-PEtn transferase genes were sequenced and their translated amino acid sequences were shown to be greater than 96% identical to that of the Lpt6 transferase from the L4 immunotype strain, which has been shown to transfer PEtn to the 6-position of the distal heptose residue. We discuss the implications of these findings with respect to the immunotyping scheme for the meningococci and in the context of LPS-based vaccine development.
Key words: core oligosaccharide / LPS/NMR / Neisseria meningitidis / phosphoethanolamine