title: Primary sequence and site-selective hydroxylation of prolines in isoforms of a major peanut allergen protein Ara h 2.
abstract: The Ara h 2 proteins are major determinants of peanut allergens. These proteins have not been fully studied at the molecular level. It has been previously proposed that there are two isoforms of Ara h 2, based on primary structures that were deduced from two reported cDNA sequences. In this report, four isoforms have been purified and characterized individually. Mass spectrometric methods have been used to determine the protein sequences and to define post-translational modifications for all four isoforms. Two pairs of isoforms have been identified, corresponding to a long-chain form and a form that is shorter by 12 amino acids. Each pair is further differentiated by the presence or absence of a two amino acid sequence at the carboxyl terminus of the protein. Modifications that were characterized include site-specific hydroxylation of proline residues, but no glycosylation was found, in contrast to previous reports.
authors: Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
authors: Jinxi
authors: J
authors: Li
authors: Kevin
authors: K
authors: Shefcheck
authors: John
authors: J
authors: Callahan
authors: Catherine
authors: C
authors: Fenselau
mesh_terms: D055516:2S Albumins, Plant / Q000737:chemistry* / Q000378:metabolism; D000485:Allergens / Q000737:chemistry* / Q000378:metabolism; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D002852:Chromatography, Ion Exchange; D004220:Disulfides; D006023:Glycoproteins / Q000737:chemistry* / Q000378:metabolism; D006900:Hydroxylation; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000737:chemistry; D011392:Proline / Q000737:chemistry* / Q000378:metabolism; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D016415:Sequence Alignment; D053719:Tandem Mass Spectrometry
chemical_list: D055516:2S Albumins, Plant; D000485:Allergens; D052179:Antigens, Plant; C500890:Ara h 2 allergen, Arachis hypogaea; D004220:Disulfides; D006023:Glycoproteins; D010446:Peptide Fragments; D020033:Protein Isoforms; D011392:Proline