3EBK

Crystal structure of major allergens, Bla g 4 from cockroaches

Summary for 3EBK

• Entry DOI: 10.2210/pdb3ebk/pdb
• Descriptor: Allergen Bla g 4 (2 entities in total)
• Functional Keywords: beta barrel, allergen, cockroach, glycoprotein, secreted
• Biological source: Blattella germanica (German cockroach)
• Cellular location: Secreted : P54962
• Total number of polymer chains: 2
• Total formula weight: 40751.51

Authors

Tan, Y.W.,Chan, S.L.,Chew, F.T.,Sivaraman, J.,Mok, Y.K. (deposition date: 2008-08-28, release date: 2008-12-02, Last modification date: 2024-10-30)

Primary citation

Tan, Y.W.,Chan, S.L.,Ong, T.C.,Yit, L.Y.,Tiong, Y.S.,Chew, F.T.,Sivaraman, J.,Mok, Y.K.
Structures of two major allergens, Bla g 4 and Per a 4, from cockroaches and their IgE binding epitopes.
J.Biol.Chem., 284:3148-3157, 2008

PubMed Abstract: Inhalant allergens from cockroaches are an important cause of asthma to millions of individuals worldwide. Here we report for the first time the structures of two major cockroach allergens, Bla g 4 and Per a 4, that adopt a typical lipocalin fold but with distinct structural features as compared with other known lipocalin allergens. Both Bla g 4 and Per a 4 contain two long-range disulfide bonds linking the N and C termini to a beta-barrel. The C-terminal helix of Bla g 4 is bent and greatly extended toward the N terminus. Bla g 4 is found to be a monomer, whereas Per a 4 exists as a dimer in solution with a novel dimeric interface involving residues from loops at the top and bottom of the beta-barrel. Putative ligand binding sites of both allergens are determined by docking of the juvenile hormone III inside the beta-barrel and found to interact with the ligand using non-conserved residues. Bla g 4 and Per a 4 are found to be cross-reactive in sera IgE binding, at least in the Singaporean Chinese population tested. A major IgE binding epitope unique to Per a 4 is found on the loops at the bottom of the beta-barrel that may aid the development of hypoallergens for immunotherapy.

PubMed: 19056737
DOI: 10.1074/jbc.M807209200

Experimental method

X-RAY DIFFRACTION (1.9 Å)