The glycoprotein allergen Ag-54 (Cla h II) from Cladosporium herbarum. Further biochemical characterization.
The carbohydrate-protein linkage of the allergen Ag-54 in the mould Cladosporium herbarum was studied after alkaline-borohydride treatment of the glycoprotein. By incorporating tritium into the peptide-linked monosaccharide through the alkaline scission of the linkage, it was demonstrated that the highly branched galactomannan moiety of Ag-54 was linked to the protein through mannose. Threonine was identified as the carbohydrate-linked amino acid. In addition, a few glucose units were peptide-linked, but the corresponding amino acids were not identified. When deglycosylated with trifluoromethanesulfonic acid, Ag-54 retained only 5% of its allergenic activity as compared to the native Ag-54 when tested by rocket immunoelectrophoresis and autoradiography. Immunological identity between native and deglycosylated Ag-54 was observed. Deglycosylation also resulted in reduced stability towards denaturation by heat or urea.
D000485:Allergens; D052179:Antigens, Plant; D002963:Cladosporium / Q000276:immunology*; D005656:Fungal Proteins / Q000032:analysis*; D005690:Galactose / Q000031:analogs & derivatives; D006031:Glycosylation; D008351:Mannans / Q000032:analysis; D003904:Mitosporic Fungi / Q000276:immunology*; D011489:Protein Denaturation; D013912:Threonine / Q000032:analysis
D000485:Allergens; D052179:Antigens, Plant; C046933:Cla h II protein, Cladosporium herbarum; D005656:Fungal Proteins; D008351:Mannans; C012990:galactomannan; D013912:Threonine; D005690:Galactose