Taxonomic group: bacteria / Firmicutes
(Phylum: Firmicutes)
Associated disease: infection due to Streptococcus pneumoniae [ICD11:
XN3PW 
]
NCBI PubMed ID: 10723608Journal NLM ID: 0043535Publisher: Elsevier
Correspondence: bpinto
sfu.ca
Institutions: Becton Dickinson Research Center, PO Box 12016, Research Triangle Park, NC 27709, USA, Department of Chemistry and Institute of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby,BC, Canada V5A 1S6
The binding of Strep 9, a mouse monoclonal antibody (mAb) of the IgG3 subclass directed against the cell-wall polysaccharide of Group A Streptococcus (GAS), has been characterized. The intact antibody and proteolytic fragments of Strep 9 bind differently to GAS: the intact mAb and F(ab)2' have greater affinity for the carbohydrate epitope than the monomeric Fab or F(ab)'. A mode of binding in which Strep 9 binds bivalently to portions of the polysaccharide on adjacent chains on GAS is proposed. A competitive ELISA protocol using a panel of carbohydrate inhibitors shows that the branched trisaccharide, β-D-GlcpNAc-(1→3)-[α-L-Rhap-(1→2)]-α-L-Rhap, and an extended surface are key components of the epitope recognized by Strep 9. Microcalorimetry measurements with the mAb and two synthetic haptens, a tetrasaccharide and a hexasaccharide, show enthalpy-entropy compensation as seen in other oligosaccharide-protein interactions. Molecular modeling of the antibody variable region by homology modeling techniques indicates a groove-shaped combining site that can readily accommodate extended surfaces. Visual docking of an oligosaccharide corresponding to the cell-wall polysaccharide into the site provides a putative model for the complex, in which a heptasaccharide unit occupies the site and the GlcpNAc residues of two adjacent branched trisaccharide units occupy binding pockets within the groove-shaped binding site.
antigen, Streptococcus, carbohydrate, group, molecular, antibodies, antibody, epitope, monoclonal, monoclonal antibodies, monoclonal antibody, specificity, fragment, modeling, epitope specificity, carbohydrate antigen
Structure type: oligomer
Location inside paper: p. 21
Contained glycoepitopes: IEDB_131174,IEDB_131175,IEDB_133754,IEDB_135610,IEDB_135813,IEDB_136105,IEDB_137340,IEDB_141807,IEDB_151531,IEDB_225177,IEDB_885823
Methods: ELISA
Biological activity: serological data
Comments, role: fragment of cell wall
3D data: molecular modeling
Related record ID(s): 4060, 4151, 4152, 4153, 4154, 4155, 4157, 4158
NCBI Taxonomy refs (TaxIDs): 1313Reference(s) to other database(s): GlycomeDB:
6025
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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