title: Cockroach allergens Per a 3 are oligomers.
abstract: Allergens from cockroaches cause major asthma-related health problems worldwide. Among them Per a 3 belongs to the most potent allergens. Although the sequences of some members of the Per a 3-family are known, their biochemical and biophysical properties have not been investigated. Here we present for the first time a thorough structural characterization of these allergens, which have recently been tested to induce an increase of allergy specific indicators in blood of Europeans. We isolated two Per a 3 isoforms, which occur freely dissolved in the hemolymph as hexamers with molecular masses of 465+/-25kDa (P II) and 512+/-25kDa (P I). Their sedimentation coefficients (S(20,W)) were determined to be 17.4+/-0.7 S (P II) and 19.0+/-0.9 S (P I), respectively. Sequence analysis revealed that P II consists of two subunit types known as allergens Per a 3.01 and Per a 3.0201, while PI consists of a new allergenic subunit type designated as Per a 3.03. A 3D model of the hexameric allergen Per a 3 was obtained by homology modelling. Almost all of the recently predicted 11 putative antigenic peptides and reported IgE-epitopes could be located on the surface of the hexamer, thus being freely accessible in the hexameric structure of the native molecules. We propose this might contribute to their allergic potential as well as their extreme stability with respect to temperature.
authors.affiliation: Institute for Molecular Biophysics, University of Mainz, Jakob Welder Weg 26, Mainz, Germany.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Mindykowski
authors.forename: Elmar
authors.initials: E
authors.lastname: Jaenicke
authors.forename: Stefan
authors.initials: S
authors.lastname: Tenzer
authors.forename: Sebahattin
authors.initials: S
authors.lastname: Cirak
authors.forename: Thorsten
authors.initials: T
authors.lastname: Schweikardt
authors.forename: Hansjoerg
authors.initials: H
authors.lastname: Schild
authors.forename: Heinz
authors.initials: H
authors.lastname: Decker
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification*; D013058:Mass Spectrometry; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010526:Periplaneta / Q000276:immunology*; D020033:Protein Isoforms; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014461:Ultracentrifugation
chemical_list: D000485:Allergens; D019476:Insect Proteins; D020033:Protein Isoforms