Structures of the K35 and K15 capsular polysaccharides of Acinetobacter baumannii LUH5535 and LUH5554 containing amino and diamino uronic acids

• Published in: Carbohydrate research 2017-08, Vol.448, p.28-34
• Main Authors: Shashkov, Alexander S., Liu, Bin, Kenyon, Johanna J., Popova, Anastasiya V., Shneider, Mikhail M., Senchenkova, Sof'ya N., Arbatsky, Nikolay P., Miroshnikov, Konstantin A., Wang, Lei, Knirel, Yuriy A.
• Format: Article
• Language: English
• Subjects: 2,3-Diacetamido-2,3-deoxy-d-glucuronic acid; 2,4-Diacetamido-2,4,6-trideoxy-d-glucose; 2-Acetamido-2-deoxy-d-galacturonic acid; Acinetobacter baumannii; Acinetobacter baumannii - chemistry; Bacterial Capsules - chemistry; Capsular polysaccharide structure; K locus; Polysaccharides, Bacterial - chemistry; Uronic Acids - chemistry
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/j.carres.2017.05.017

Capsular polysaccharides were isolated from A. baumannii LUH5535 (K35 CPS) and LUH5554 (K15 CPS) and studied by 1D and 2D 1H and 13C NMR spectroscopy. The CPSs were found to consist of linear tetrasaccharide repeats (K units) containing 2-acetamido-2-deoxy-d-galacturonic acid (K35) or 2,3-diacetamido-2,3-deoxy-d-glucuronic acid (K15) and 2,4-diacetamido-2,4,6-trideoxy-d-glucose (both CPSs). The K35 unit includes three O-acetyl groups on different GalNAcA residues. A. baumannii LUH5535 and LUH5554 carry the KL35 and KL15 gene clusters, respectively, and putatively assigned functions of genes in these clusters were consistent with the CPS structures established. [Display omitted] •Capsular polysaccharides were isolated from two Acinetobacter baumannii strains.•The polysaccharides are enriched in amino and diamino sugars, including uronic acids.•Structures of the polysaccharides were established by NMR and chemical approaches.•Capsule biosynthesis gene clusters were analyzed and found to match the structures established.