Structure of an acidic O-specific polysaccharide of Pseudoalteromonas haloplanktis type strain ATCC 14393 containing 2-acetamido-2-deoxy-D- and -L-galacturonic acids and 3-(N-acetyl-D-alanyl)amino-3,6-dideoxy-D-glucose

An acidic O-specific polysaccharide was obtained from the lipopolysaccharid e of Pseudoalteromonas haloplanktis ATCC 14393 and found to contain D-galac tose, 3-(N-acetyl-D-alanyl)amino-3,6-dideoxy-D-glucose (D-Qui3NDAlaAc), 2,4 -diacetamido-2,4,6-trideoxy-D-glucose (D-QuiNAc4NAc), 2-acetamido-2-deoxy-D - and -L-galacturonic acids (D- and L-GalNAcA), and O-acetyl groups. On the basis of Smith degradation and H-1 and C-13 NMR spectroscopic studies, inc luding 2D COSY, TOCSY, NOESY, H-1, C-13 HMQC, and HMBC experiments, the fol lowing structure of the pentasaccharide repeating unit of the polysaccharid e was established: --> 4)-alpha-L-GalpNAcA-(1 --> 3)-beta-D-Quip NAc4NAc-(1 --> 2)-beta-D-Quip 3NDAlaAc-(1 --> 4)-alpha-D-GalpNAcA-(1 --> 4) -alpha-D-Galp2,6Ac(2)-(1 --> where O-acetylation of the galactose residue at each position is partial (5 0-70%). (C) 1999 Elsevier Science Ltd. All rights reserved.