Hummel Marlene, Wigger Tina, Brockmeyer Jens
Department of Chemistry, Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster , Corrensstr. 45, 48149 Münster, Germany.
J Proteome Res. 2015 Mar 6;14(3):1547-56. doi: 10.1021/pr5012262. Epub 2015 Feb 20.
The mustard allergen Sin a 1 belongs to the 2S-albumin family of seed-storage proteins. Because of its high abundance in mustard seeds and the potential to elicit severe allergenic reactions, Sin a 1 is considered to be a major allergen in mustard. Eight Sin a 1 isoforms have been identified using DNA cloning and sequencing, and we aim in this study to thoroughly investigate sequence heterogeneity using a novel combination of bottom-up, middle-down, and top-down proteomics. The characterization of purified Sin a 1 extract shows that sequence diversity is far more pronounced than previously assumed. We identified in total 24 sequence polymorphisms including 17 yet unpublished point mutations. Using middle-down and top-down approaches on the subunit and protein level of Sin a 1, we were able to detect eight consensus isoforms of Sin a 1(including four novel isoforms), which we detect in the majority of the four different mustard samples included in this study. In addition, we provide for the first time data on relative abundance of the main Sin a 1 isoforms and identify phytic acid as a potential ligand of Sin a 1. Together, these data can form the basis for a more detailed investigation of the effect of Sin a 1 polymorphic sites on allergenicity of isoforms.
芥菜过敏原Sin a 1属于种子储存蛋白的2S白蛋白家族。由于其在芥菜种子中的高丰度以及引发严重过敏反应的可能性，Sin a 1被认为是芥菜中的主要过敏原。通过DNA克隆和测序已鉴定出8种Sin a 1亚型，我们在本研究中的目标是使用自下而上、中而下和自上而下的蛋白质组学新组合来全面研究序列异质性。纯化的Sin a 1提取物的表征表明，序列多样性比以前假设的要明显得多。我们总共鉴定出24种序列多态性，包括17种尚未发表的点突变。在Sin a 1的亚基和蛋白质水平上使用中而下和自上而下的方法，我们能够检测到Sin a 1的8种共有亚型（包括4种新亚型），我们在本研究中纳入的四种不同芥菜样品中的大多数中都检测到了这些亚型。此外，我们首次提供了主要Sin a 1亚型相对丰度的数据，并确定植酸是Sin a 1的潜在配体。这些数据共同可为更详细地研究Sin a 1多态性位点对亚型过敏原性的影响奠定基础。
