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Structure type: polymer chemical repeating unit
Compound class: CPS
Contained glycoepitopes: IEDB_136044,IEDB_136105,IEDB_137472,IEDB_141794,IEDB_190606,IEDB_225177,IEDB_885823,SB_165,SB_166,SB_187,SB_195,SB_7,SB_88

• Article ID: 6136
  Senchenkova SN, Shashkov AS, Shneider MM, Popova AV, Balaji V, Biswas I, Knirel YA, Kenyon JJ "A novel ItrA4 D-galactosyl 1-phosphate transferase is predicted to initiate synthesis of an amino sugar-lacking K92 capsular polysaccharide of Acinetobacter baumannii B8300" - Research in Microbiology 172(3) (2021) 103815
  

  The K92 capsular polysaccharide (CPS) from Acinetobacter baumannii B8300 was studied by sugar analysis, Smith degradation, and one- and two-dimensional 1H and 13C NMR spectroscopy. The elucidated CPS includes a branched pentasaccharide repeat unit containing one d-Galp and four l-Rhap residues; an atypical composition given that all A. baumannii CPS structures determined to date contain at least one amino sugar. Accordingly, biosynthesis of A. baumannii CPS types are initiated by initiating transferases (Itrs) that transfer 1-phosphate of either a 2-acetamido-2-deoxy-d-hexose, a 2-acetamido-2,6-dideoxy-d-hexose or a 2-acetamido-4-acylamino-2,4,6-trideoxy-d-hexose to an undecaprenyl phosphate (UndP) carrier. However, the KL92 capsule biosynthesis gene cluster in the B8300 genome sequence includes a gene for a novel Itr type, ItrA4, which is predicted to begin synthesis of the K92 CPS by transferring D-Galp 1-phosphate to the UndP lipid carrier. The itrA4 gene was found in a module transcribed in the opposite direction to the majority of the K locus. This module also includes an unknown open reading frame (orfKL92), a gtr166 glycosyltransferase gene, and a wzi gene predicted to be involved in the attachment of CPS to the cell surface. Investigation into the origins of orfKL92-gtr166-itrA4-wziKL92 revealed it might have originated from Acinetobacter junii.

  Acinetobacter baumannii, capsular polysaccharide, capsule biosynthesis, galactosyl 1-phosphate transferase, initiating transferase, ItrA4

  NCBI PubMed ID: 33667610
  Publication DOI: 10.1016/j.resmic.2021.103815
  Journal NLM ID: 8907468
  Publisher: Elsevier
  Correspondence: johanna.kenyon@qut.edu.au
  Institutions: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia, State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russia, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia, M.M. Shemyakin & Y.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Australia, Department of Clinical Microbiology, Christian Medical College, Vellore, 632004, Tamil Nadu, India, Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
  Methods: 13C NMR, 1H NMR, periodate oxidation, NMR-2D, GLC, Smith degradation, composition analysis, HPLC, GPC, bioinformatic analysis
  
   
  
  Acinetobacter baumannii K92 B8300
  CSDB ID 10936 (all data & tools)
• Article ID: 6217
  Drobiazko AY, Kasimova AA, Evseev PV, Schneider MM, Klimuk EI, Shashkov AS, Dmitrenok AS, Chizhov AO, Slukin PV, Skryabin YP, Volozhantsev NV, Miroshnikov KA, Knirel YA, Popova AV "Capsule-Targeting Depolymerases Derived from Acinetobacter baumannii Prophage Regions" - International Journal of Molecular Sciences 23(9) (2022) 4971
  

  In this study, several different depolymerases encoded in the prophage regions of Acinetobacter baumannii genomes have been bioinformatically predicted and recombinantly produced. The identified depolymerases possessed multi-domain structures and were identical or closely homologous to various proteins encoded in other A. baumannii genomes. This means that prophage-derived depolymerases are widespread, and different bacterial genomes can be the source of proteins with polysaccharide-degrading activities. For two depolymerases, the specificity to capsular polysaccharides (CPSs) of A. baumannii belonging to K1 and K92 capsular types (K types) was determined. The data obtained showed that the prophage-derived depolymerases were glycosidases that cleaved the A. baumannii CPSs by the hydrolytic mechanism to yield monomers and oligomers of the K units. The recombinant proteins with established enzymatic activity significantly reduced the mortality of Galleria mellonella larvae infected with A. baumannii of K1 and K92 capsular types. Therefore, these enzymes can be considered as suitable candidates for the development of new antibacterials against corresponding A. baumannii K types.

  Acinetobacter baumannii, capsular polysaccharide, glycosidase, capsular type, phage receptor-binding proteins, prophages, structural depolymerase

  NCBI PubMed ID: 35563361
  Publication DOI: 10.3390/ijms23094971
  Journal NLM ID: 101092791
  Publisher: Basel, Switzerland: MDPI
  Correspondence: A.V. Popova
  Institutions: N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia, Moscow Institute of Physics and Technology (National Research University), 141700 Dolgoprudny, Russia, Center of Life Sciences, Skolkovo Institute of Science and Technology, 121205 Skolkovo, Russia, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», 123182 Moscow, Russia, State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia
  Methods: 13C NMR, 1H NMR, NMR-2D, PCR, DNA techniques, mild acid hydrolysis, de-O-acetylation, HPLC, GPC, bioinformatic analysis, phylogenetic analysis, HR-ESI-MS, phage characterization, BLASTp, phage depolymerization
  
   
  
  Acinetobacter baumannii K92 B8300
  CSDB ID 20931 (all data & tools)