The pH 6 antigen of Yersinia pestis binds to beta1-linked galactosyl residues in glycosphingolipids.
The Yersinia pestis pH 6 antigen was expressed by, and purified from, Escherichia coli containing cloned psa genes. By an enzyme-linked immunosorbence-based assay, purified pH 6 antigen bound to gangliotetraosylceramide (GM1A), gangliotriaosylceramide (GM2A), and lactosylceramide (LC) (designations follow the nomenclature of L. Svennerholm [J. Neurochem. 10:613-623, 1963]). Binding to GM1A, GM2A, and LC was saturable, with 50% maximal binding occurring at 498 +/- 4, 390, and 196 +/- 3 nM, respectively. Thin-layer chromatography (TLC) overlay binding confirmed that purified pH 6 antigen bound to GM1A, GM2A, and LC and also revealed binding to hydroxylated galactosylceramide. Intact E. coli cells which expressed the pH 6 antigen had a specificity similar to that of purified pH 6 in the TLC overlay assay except that nonhydroxylated galactosylceramide was also bound. The binding patterns observed indicate that the presence of beta1-linked galactosyl residues in glycosphingolipids is the minimum determinant required for binding of the pH 6 antigen.
Defence Evaluation and Research Agency, CBD Porton Down, Porton Down, Salisbury, Wiltshire SP4 OJQ, United Kingdom.
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D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000378:metabolism*; D002240:Carbohydrate Sequence; D005678:G(M2) Ganglioside / Q000031:analogs & derivatives; D005732:Gangliosides; D006028:Glycosphingolipids / Q000378:metabolism*; D007790:Lactosylceramides / Q000378:metabolism; D008969:Molecular Sequence Data; D015010:Yersinia pestis / Q000378:metabolism*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C011258:G(A1) ganglioside; D005732:Gangliosides; D006028:Glycosphingolipids; D007790:Lactosylceramides; C081814:pH 6 antigen, Yersinia; D005678:G(M2) Ganglioside