BACKGROUND: Ara h 2 is a major peanut allergen recognized by IgE in more than 90% of patients. After electrophoretic separation the purified protein exists as a doublet, and sequences of one incomplete cDNA and one genomic clone for this allergen have been reported. METHODS: Ara h 2 isoforms were purified and analyzed by mass spectroscopy, and PCR amplification products of Ara h 2 were cloned and sequenced. RESULTS: Mass spectroscopy of purified Ara h 2 clearly identified a molecular doublet of 16,670 and 18,050 Daltons. Amplification of a peanut cDNA library using PCR primer pairs located at the amino- and carboxy-terminus revealed 2 bands separated by 50 base pairs, which we cloned and sequenced. Two types of complete cDNA clones were obtained, Ara h 2.01 and Ara h 2.02. Compared to Ara h 2.01 and the previously reported cDNA sequences, Ara h 2.02 is characterized by a 12 amino acid insertion starting at position 75 that contains a third repeat of the major IgE binding epitope DPYSPS. CONCLUSION: We demonstrated the molecular and genetic characteristics of two Ara h 2 isoforms, revealing that one, Ara h 2.02, might be the more potent allergen. Copyright 2003 S. Karger AG, Basel
BACKGROUND: Ara h 2 is a major peanut allergen recognized by IgE in more than 90% of patients. After electrophoretic separation the purified protein exists as a doublet, and sequences of one incomplete cDNA and one genomic clone for this allergen have been reported. METHODS: Ara h 2 isoforms were purified and analyzed by mass spectroscopy, and PCR amplification products of Ara h 2 were cloned and sequenced. RESULTS: Mass spectroscopy of purified Ara h 2 clearly identified a molecular doublet of 16,670 and 18,050 Daltons. Amplification of a peanut cDNA library using PCR primer pairs located at the amino- and carboxy-terminus revealed 2 bands separated by 50 base pairs, which we cloned and sequenced. Two types of complete cDNA clones were obtained, Ara h 2.01 and Ara h 2.02. Compared to Ara h 2.01 and the previously reported cDNA sequences, Ara h 2.02 is characterized by a 12 amino acid insertion starting at position 75 that contains a third repeat of the major IgE binding epitope DPYSPS. CONCLUSION: We demonstrated the molecular and genetic characteristics of two Ara h 2 isoforms, revealing that one, Ara h 2.02, might be the more potent allergen. Copyright 2003 S. Karger AG, Basel
Authors: Katrin Lehmann; Kristian Schweimer; Gerald Reese; Stefanie Randow; Martin Suhr; Wolf-Meinhard Becker; Stefan Vieths; Paul Rösch Journal: Biochem J Date: 2006-05-01 Impact factor: 3.857