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The major Platanus acerifolia pollen allergen Pla a 1 has sequence homology to invertase inhibitors
Author(s) -
Asturias J. A.,
Ibarrola I.,
Eraso E.,
Arilla M. C.,
Martínez A.
Publication year - 2003
Publication title -
clinical and experimental allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 154
eISSN - 1365-2222
pISSN - 0954-7894
DOI - 10.1046/j.1365-2222.2003.01707.x
Subject(s) - recombinant dna , microbiology and biotechnology , allergen , complementary dna , fusion protein , biology , immunoglobulin e , peptide sequence , escherichia coli , molecular cloning , biochemistry , chemistry , antibody , gene , allergy , immunology
Summary Background Sycamores or plane trees are an important source of airborne allergens in many cities of the United States and Western Europe. Pla a 1 has been described as a major allergen from Platanus acerifolia (London plane tree). Objective To clone and characterize the cDNA for Pla a 1 and to express the recombinant protein. Methods Pla a 1 was isolated by cationic exchange, gel filtration, and reverse‐phase chromato‐graphies. Pla a 1 cDNA was cloned by reverse transcription followed by polymerase chain reaction, using amino acid sequences from tryptic peptides of the allergen. The Pla a 1 encoding sequence has been subcloned into the pKN172 expression vector and expressed in Escherichia coli as a non‐fusion protein. Purified recombinant protein has been tested for its IgE‐binding capacity in immunoblot, immunoblot inhibition, and ELISA. Results Pla a 1 reacted with serum IgE from 35 of the 42 (83.3%) Platanus‐ allergic patients studied and represented 60% of the total IgE‐binding capacity of the P. acerifolia pollen extract. The allergen displayed 43% sequence identity to a grape invertase inhibitor and showed a predicted secondary structure characteristic of all‐alpha proteins. Serological analysis revealed that both natural and recombinant forms of Pla a 1 displayed similar IgE‐binding capacity. Conclusions Pla a 1 belongs to a new class of allergens related to proteinaceous invertase inhibitors. Recombinant Pla a 1 binds IgE in vitro like its natural counterpart and, therefore, it can be useful for specific diagnosis and structural studies.