The unique structure of complete lipopolysaccharide isolated from semi-rough Plesiomonas shigelloides O37 (strain CNCTC 39/89) containing (2S)-O-(4-oxopentanoic acid)-α-d-Glcp (α-d-Lenose)

Abstract

The complete structure of semi-rough lipopolysaccharide (SR-LPS) of Plesiomonas shigelloides CNCTC 39/89 (serotype O37) has been investigated by 1H and 13C NMR spectroscopy, matrix-assisted laser-desorption/ionization time-of-flight MS, and chemical methods. The following structure of the single unit of the O-antigen has been established: [Display omitted] in which α-d-Lenp is (2S)-O-(4-oxopentanoic acid)-α-d-Glcp residue which has not been found in nature. The absolute configuration of oxopentanoic acid moiety in α-d-Lenose residue was determined by NOESY experiment combined with molecular modeling (MM2 force field). The decasaccharide core is substituted at C-4 of the β-d-Glcp residue with a single pentasaccharide unit. Lipid A is built of a β-d-GlcpN4P-(1→6)-α-d-GlcpN1P disaccharide asymmetrically substituted with fatty acids. It was concluded that the core oligosaccharide and the lipid A are identical with those in P. shigelloides CNCTC 113/92 Niedziela et al. (2002)9 and Lukasiewicz et al. (2006).10