Structure of the K87 capsular polysaccharide and KL87 gene cluster of Acinetobacter baumannii LUH5547 reveals a heptasaccharide repeating unit

Nikolay P Arbatsky; Anastasiya V Popova; Mikhail M Shneider; Alexander S Shashkov; Ruth M Hall; Johanna J Kenyon; Yuriy A Knirel

doi:10.1016/j.carres.2021.108439

Structure of the K87 capsular polysaccharide and KL87 gene cluster of Acinetobacter baumannii LUH5547 reveals a heptasaccharide repeating unit

Carbohydr Res. 2021 Nov:509:108439. doi: 10.1016/j.carres.2021.108439. Epub 2021 Sep 7.

Authors

Nikolay P Arbatsky¹, Anastasiya V Popova², Mikhail M Shneider³, Alexander S Shashkov¹, Ruth M Hall⁴, Johanna J Kenyon⁵, Yuriy A Knirel¹

Affiliations

¹ N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia.
² Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia; State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russia.
³ M. M. Shemyakin & Y. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.
⁴ School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia.
⁵ Centre for Immunology and Infection Control, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology. Brisbane, Australia. Electronic address: johanna.kenyon@qut.edu.au.

PMID: 34555685
DOI: 10.1016/j.carres.2021.108439

Abstract

K87 capsular polysaccharide (CPS) was isolated from Acinetobacter baumannii isolate LUH5547 that carries the KL87 capsule biosynthesis gene cluster at the chromosomal K locus. Studies by sugar analysis, selective chemical cleavages, and 1D and 2D ¹H and ¹³C NMR spectroscopy showed that the CPS has a branched heptasaccharide repeat (K unit) containing one residue each of d-glucose (d-Glсp), d-glucuronic acid (d-GlсpA), N-acetyl-d-glucosamine (d-GlсpNAc), 6-deoxy-l-talose (l-6dTalp), and three residues of l-rhamnose (l-Rhap). The following structure of the CPS was established: →3)-α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-6dTalp-(1→3)-β-D-GlcpNAc-(1→2↑1β-D-GlcpA-(4←1)-α-D-Glcp(2←1)-α-L-Rhap The position of a minor O-acetyl group present in the CPS was not determined. Functions of enzymes coded by genes in the KL87 gene cluster were tentatively assigned and found to be consistent with the CPS structure.

Keywords: 6-Deoxy-l-talose; Acinetobacter baumannii; Capsular polysaccharide; K locus; K87.

MeSH terms

Acinetobacter baumannii*