Structure elucidation of the capsular polysaccharide of Acinetobacter baumannii AB5075 having the KL25 capsule biosynthesis locus

Capsular polysaccharide was isolated by the phenol-water extraction of Acinetobacter baumannii AB5075 and studied by 1D and 2D H-1 and C-13 NMR spectroscopy. The following structure of the linear trisaccharide repeating unit was established: -> 3)-beta-D-ManpNAcA-(1 -> 4)-beta-D-ManpNAcA-(1 -> 3)-alpha-D-QuipNAc4NR- (1 -> where R indicates (S)-3-hydroxybutanoyl or acetyl in the ratio similar to 2.5:1. The genes in the polysaccharide biosynthesis locus designated KL25 are appropriate to the established CPS structure. (C) 2015 Elsevier Ltd. All rights reserved.