title: Characterization of a novel allergen, a major IgE-binding protein from Aspergillus flavus, as an alkaline serine protease.
abstract: Aspergillus species of fungi have been known to be one of the most prevalent aeroallergens. One important A. flavus allergen (Asp fl 1) was identified by means of immunoblotting with a serum pool of allergic patients on a two-dimensional electrophoretic gel. The cDNA coding for Asp fl 1 was cloned and sequenced. The clone encodes a full-length protein of 403 amino acid precursors of 42 kDa. After cleavage of a putative signal peptide of 21 amino acids and a prepeptide of 100 amino acids, a mature protein of 282 amino acids was obtained with a molecular mass of 33 kDa and a pI of 6.3. A degree of identity was found in a range of 27 to 84% among related allergens derived from bacteria allergen subtilisin, mold allergen Pen c 1, and virulence factor of A. fumigatus. Recombinant Asp fl 1 (rAsp fl 1) was cloned into vector pQE-30 and expressed in E. coli M15 as a histidine-tag fusion protein and purified to homogeneity. The IgE binding capacity of rAsp fl 1 was tested by immunoblotting using a serum pool of Aspergillus-allergic patients. Recombinant allergen cross-reacted strongly with IgE specific for natural Asp fl 1 and Pen c 1, indicating that common IgE epitopes may exist between allergens of A. flavus and P. citrinum.
authors.affiliation: Institute of Biochemistry, College of Medicine, National Taiwan University, Institute of Biological Chemistry, Academia, Taipei, Taiwan.
authors.forename: C J
authors.initials: CJ
authors.lastname: Yu
authors.forename: S H
authors.initials: SH
authors.lastname: Chiou
authors.forename: W Y
authors.initials: WY
authors.lastname: Lai
authors.forename: B L
authors.initials: BL
authors.lastname: Chiang
authors.forename: L P
authors.initials: LP
authors.lastname: Chow
mesh_terms: D000485:Allergens / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D000595:Amino Acid Sequence; D001231:Aspergillus flavus / Q000276:immunology*; D001483:Base Sequence; D015180:Electrophoresis, Gel, Two-Dimensional; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017385:Sequence Homology; D012697:Serine Endopeptidases / Q000032:analysis* / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*
chemical_list: D000485:Allergens; C120961:Asp fl 1 allergen; D007073:Immunoglobulin E; D012697:Serine Endopeptidases