title: A molecular and in silico characterization of Hev b 4, a glycosylated latex allergen.
abstract: Hev b 4 is a heavily glycosylated latex allergen with seven attached N-glycans, comprising of both oligomannose and complex type structures. Treatment with a mixture of N-glycosidase A and N-glycosidase F resulted in lowering Hev b 4 protein on SDS-gel from 53 to 55kDa to circa 40kDa, this being comparable to the 38.53kDa mass predicted by its cDNA. In Western-immunoblots, the enzymatically deglycosylated Hev b 4 showed negligible binding to IgE from latex allergic patients; the results indicated that IgE essentially binds to Hev b 4 via its N-glycan moiety. Structural modelling of the Hev b 4 was carried out based on the template protein and carbohydrate crystal coordinates of rhamnogalacturonan acetylesterase (PDB ID 1DEO). We managed to link four N-glycan structures on to the Hev b 4 model; the glycans were scattered over the surface of the model. The structural and functional features of Hev b 4 could prove useful to elucidate its exposed epitopes which are important for IgE binding.
authors.affiliation: Department of Biosciences, Jamia Millia Islamia, New Delhi 110025, India.
authors.forename: Adeel
authors.initials: A
authors.lastname: Malik
authors.forename: Siti Arija M
authors.initials: SA
authors.lastname: Arif
authors.forename: Shandar
authors.initials: S
authors.lastname: Ahmad
authors.forename: Elumalai
authors.initials: E
authors.lastname: Sunderasan
mesh_terms: D000485:Allergens / Q000737:chemistry* / Q000145:classification / Q000276:immunology*; D052179:Antigens, Plant / Q000737:chemistry* / Q000145:classification / Q000276:immunology*; D019295:Computational Biology; D019143:Evolution, Molecular; D006031:Glycosylation; D007136:Immunoglobulins / Q000276:immunology; D007840:Latex / Q000737:chemistry* / Q000276:immunology*; D008958:Models, Molecular; D010740:Phospholipases / Q000737:chemistry* / Q000145:classification / Q000276:immunology*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012997:Solvents
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D007136:Immunoglobulins; D007840:Latex; D012997:Solvents; C510766:Hev b 4 allergen, Hevea brasiliensis; D010740:Phospholipases