Production of the K16 capsular polysaccharide by Acinetobacter baumannii ST25 isolate D4 involves a novel glycosyltransferase encoded in the KL16 gene cluster

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

doi:10.1016/j.ijbiomac.2019.01.080

Production of the K16 capsular polysaccharide by Acinetobacter baumannii ST25 isolate D4 involves a novel glycosyltransferase encoded in the KL16 gene cluster

Int J Biol Macromol. 2019 May 1:128:101-106. doi: 10.1016/j.ijbiomac.2019.01.080. Epub 2019 Jan 18.

Authors

Johanna J Kenyon¹, Nikolay P Arbatsky², Emma L Sweeney³, Alexander S Shashkov², Mikhail M Shneider⁴, Anastasia V Popova⁵, Ruth M Hall⁶, Yuriy A Knirel²

Affiliations

¹ Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Australia. Electronic address: johanna.kenyon@qut.edu.au.
² N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia.
³ Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Australia.
⁴ M. M. Shemyakin & Y. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia; Institute of Antimicrobial Chemotherapy, Smolensk State Medical University, Smolensk, Russia.
⁵ Institute of Antimicrobial Chemotherapy, Smolensk State Medical University, Smolensk, Russia; Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia; State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russia.
⁶ School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia.

PMID: 30664967
DOI: 10.1016/j.ijbiomac.2019.01.080

Abstract

A new capsular polysaccharide (CPS) biosynthesis gene cluster, KL16, was found in the genome sequence of a clinical Acinetobacter baumannii ST25 isolate, D4. The variable part of KL16 contains a module of genes for synthesis of 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-non-2-ulosonic acid (5,7-di-N-acetylpseudaminic acid, Pse5Ac7Ac), a gene encoding ItrA3 that initiates the CPS synthesis with d-GlcpNAc, and two glycosyltransferase (Gtr) genes. The K16 CPS was studied by sugar analysis and Smith degradation along with 1D and 2D ¹H and ¹³C NMR spectroscopy, and shown to be built up of linear trisaccharide repeats containing d-galactose (d-Gal), N-acetyl-d-glucosamine (d-GlcNAc), and Pse5Ac7Ac. The d-Galp residue is linked to the d-GlcpNAc initiating sugar via a β-(1 → 3) linkage evidently formed by a Gtr5 variant, Gtr5_K16, encoded in KL16. This reveals an altered or relaxed substrate specificity of this variant as the majority of Gtr5-type glycosyltransferases have previously been shown to form a β-d-Galp-(1 → 3)-d-GalpNAc linkage. The β-Psep5Ac7Ac-(2 → 4)-d-Galp linkage is predicted to be formed by the other glycosyltransferase, Gtr37, which does not match members of any known glycosyltransferase family.

Keywords: 5,7-Di-N-acetylpseudaminic acid; Acinetobacter baumannii; Capsular polysaccharide; Glycosyltransferase; KL16 K locus.

MeSH terms

Acinetobacter baumannii / genetics*
Acinetobacter baumannii / metabolism*
Bacterial Capsules / metabolism*
Gene Expression Regulation, Bacterial
Gene Order
Genes, Bacterial
Genetic Linkage
Genetic Loci
Glycosyltransferases / chemistry
Glycosyltransferases / genetics*
Glycosyltransferases / metabolism*
Magnetic Resonance Spectroscopy
Multigene Family*
Polysaccharides, Bacterial / biosynthesis*
Polysaccharides, Bacterial / chemistry

Substances

Polysaccharides, Bacterial
Glycosyltransferases