STRUCTURE OF A HIGHLY ACIDIC O-SPECIFIC POLYSACCHARIDE OF LIPOPOLYSACCHARIDE OF PSEUDOALTEROMONAS-HALOPLANKTIS-KMM-223 (44-1) CONTAINING L-IDURONIC ACID AND D-QUINHB4NHB

An acidic O-specific polysaccharide was obtained by mild acid degradat ion of the lipopolysaccharide isolated by phenol-water extraction of P seudoalteromonas haloplanktis strain KMM 223 (44-1). L-Iduronic acid ( IdoA) was found to be a component of the polysaccharide and identified by NMR spectroscopy and after carboxyl-reduction followed by acid hyd rolysis and acetylation, by GLC-MS as 2,3,4-tri-O-acetyl-1,6-anhydroid ose. On the basis of H-1 and C-13 NMR spectroscopic studies, including 1D NOE, 2D NOESY, HSQC and HMBC experiments, the following structure of the branched pentasaccharide repeating unit of the polysaccharide w as established: [GRAPHICS] where QuiNAc4NAc and QuiNHb4NHb are 2,4-dia cetamido-2,4,6-trideoxyglucose and 6-trideoxy-2,4-di[(S)-3-hydroxybuty ramido]glucose, respectively. This is the first report of L-iduronic a cid in a lipopolysaccharide and of D-QuiNHb4NHb in nature. (C) 1998 El sevier Science Ltd. All rights reserved.