Whole genome sequence from Acinetobacter baumannii isolate Ab-46-1632 reveals a novel KL144 capsular polysaccharide (CPS) biosynthesis gene cluster, which carries genes for d-glucuronic acid (D-GlcA) and l-rhamnose (l-Rha) synthesis. The CPS was extracted from Ab-46-1632 and studied by 1H and 13C NMR spectroscopy, including a two-dimensional 1H,13C HMBC experiment and Smith degradation. The CPS was found to have a hexasaccharide repeat unit composed of four l-Rhap residues and one residue each of d-GlcpA and N-acetyl-d-glucosamine (D-GlcpNAc) consistent with sugar synthesis genes present in KL144. The K144 CPS structure was established and found to be related to those of A. baumannii K55, K74, K85, and K86. A comparison of the corresponding gene clusters to KL144 revealed a number of shared glycosyltransferase genes correlating to shared glycosidic linkages in the structures. One from the enzymes, encoded by only KL144 and KL86, is proposed to be a novel multifunctional rhamnosyltransfaerase likely responsible for synthesis of a shared α-l-Rhap-(1→2)-α-L-Rhap-(1→3)-L-Rhap trisaccharide fragment in the K144 and K86 structures.
Acinetobacter baumannii, capsular polysaccharide, K locus, K144, K86, multifunctional glycosyltransferase
NCBI PubMed ID: 34757131Publication DOI: 10.1016/j.ijbiomac.2021.10.178Journal NLM ID: 7909578Publisher: Butterworth-Heinemann
Correspondence: asyashpirt@gmail.com
Institutions: Central Scientific Research Institute of Epidemiology, Moscow, Russia, Centre for Immunology and Infection Control, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology. Brisbane, Australia, D.I. Mendeleev University of Chemical Technology of Russia, Moscow, Russia, N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Science, Moscow, Russia, M.M. Shemyakin and Y.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, Moscow, Russia, State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow, Region, Russia
Methods: 13C NMR, 1H NMR, NMR-2D, sugar analysis, acid hydrolysis, GLC, Smith degradation, GPC, bioinformatic analysis, HR-ESI-MS, sequencing
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