Taxonomic group: bacteria / Chlamydiae
(Phylum: Chlamydiae)
Associated disease: infection due to Chlamydia [ICD11:
XN27H 
]
NCBI PubMed ID: 10642603Journal NLM ID: 9104124Publisher: IRL Press at Oxford University Press
Institutions: Division of Biochemical and Medical Microbiology, Borstel Research Center, Borstel, Germany, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, Canada K1A OR6, Department of Biochemistry, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5, Institute of Chemistry, University of Agriculture, A-1190 Vienna, Austria
Pathogens belonging to the genus Chlamydia contain lipopolysaccharide with a 3-deoxy-D-manno- oct-2-ulosonic acid (Kdo) trisaccharide of the sequence α-Kdo-(2→8)-α-Kdo-(2→4)-α-Kdo. This lipopolysaccharide is recognized in a genus-specific pattern by murine monoclonal antibodies (mAbs), S25-23 and S25-2 (both IgG1kappa), which bind as the minimal structures the trisaccharide and the terminal Kdo-disaccharide, respectively. The variable domains of these mAbs were reverse transcribed from mRNA which was isolated from hybridomas and cloned as single-chain variable fragments (scFvs) in Escherichia coli TG1. The kinetics of binding of whole antibodies, Fab fragments and scFvs to natural and synthetically modified ligands were determined by surface plasmon resonance (SPR) using synthetic neoglycoconjugates. As examples of an antibody-carbohydrate interaction involving anionic carboxyl groups on the ligand, we report that the affinities of these antibodies are higher than usually observed in carbo-hydrate-protein interactions (K(D)of 10(-3)to 10(-5)M). SPR analy-ses of monovalent Fab and scFv binding to the natural trisaccharide epitope gave dissociation constants of 770 nM for S25-2 and 350 nM for S25-23, as determined by global fitting (simultaneous fitting of several measurements at different antibody concentrations) of sensorgram data to a one-to-one interaction model. Local fitting (separate fitting of individual sensorgram data at different antibody concentrations) and Scatchard analysis of the data gave kinetic and affinity constants that were in good agreement with those obtained by global fitting. The SPR data also showed that while S25-2 bound well to several Kdo disaccharides and carboxyl-reduced Kdo ligands, S25-23 did not. Identification of amino acids in the complementarity determining regions revealed the presence of a large number of positively charged amino acids which were located towards the center of the combining site, thus suggesting a different recognition mechanism than that observed for neutral ligands. The latter mainly involves aromatic amino acids for hydrophobic stacking inter-actions and hydrogen bonds.
Lipopolysaccharide, characterization, antibodies, antibody, monoclonal, monoclonal antibodies, monoclonal antibody, high, specific, chlamydial, affinity
Structure type: oligomer
Location inside paper: Fig.1
Aglycon: (CH2)3S(CH2)2NHCSNH-BSA
Contained glycoepitopes: IEDB_130650,IEDB_130657,IEDB_130658,IEDB_130659
Biological activity: binding with murine monoclonal antibodies S25-23 and S25-2
Biosynthesis and genetic data: genetic data
Related record ID(s): 3806
NCBI Taxonomy refs (TaxIDs): 810Reference(s) to other database(s): GTC:G30068VP, GlycomeDB:
5771
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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