Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
Protein Sci. 2010 Jan;19(1):174-82. doi: 10.1002/pro.295.
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.
Ara h 2 蛋白是花生过敏原的主要决定因素。这些蛋白质在分子水平上尚未得到充分研究。先前曾提出基于从两个报道的 cDNA 序列推断的一级结构，存在两种 Ara h 2 同工型。在本报告中，已经单独纯化和表征了四个同工型。质谱方法已用于确定所有四个同工型的蛋白质序列和定义翻译后修饰。已经鉴定了两对同工型，对应于长链形式和短 12 个氨基酸的形式。每对同工型进一步通过蛋白羧基末端存在或不存在两个氨基酸序列来区分。鉴定的修饰包括脯氨酸残基的特异性羟化，但与先前的报道相反，没有发现糖基化。
