van Boxtel Evelien L, van den Broek Lambertus A M, Koppelman Stef J, Vincken Jean-Paul, Gruppen Harry
Laboratory of Food Chemistry, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands.
J Agric Food Chem. 2007 Oct 17;55(21):8772-8. doi: 10.1021/jf071585k. Epub 2007 Sep 21.
Mildly extracted peanut allergen Ara h 1 was previously reported to occur as an oligomeric complex. In this paper we describe how the protein in this oligomeric complex interacts noncovalently with phenolic compounds of the proanthocyanidin type. These interactions are being disrupted during anion exchange chromatography, resulting in the dissociation of the oligomeric Ara h 1 complex into protein trimers. By use of the known three-dimensional structure of beta-conglycinin, a soy protein homologous to Ara h 1, proline-rich regions were observed in silico on both faces of its trimeric structure, which are conserved in Ara h 1. These proline-rich regions could explain the binding of proanthocyanidins to Ara h 1 and the formation of multiple Ara h 1 trimer complexes. This was supported by the observation that the addition of peanut proanthocyanidins to trimeric Ara h 1 and to beta-conglycinin resulted in the formation of soluble oligomeric protein complexes. The structurally related legumin proteins do not contain such proline-rich regions on both sides of the protein, and proanthocyanidins were shown to have a lower affinity for legumin proteins from peanuts and soybeans (peanut allergen Ara h 3 and soy glycinin, respectively). Ara h 1 present as the oligomeric complex is assumed to be the representative form of the allergen in which it is consumed by humans.
先前有报道称，轻度提取的花生过敏原Ara h 1以寡聚复合物的形式存在。在本文中，我们描述了这种寡聚复合物中的蛋白质如何与原花青素类型的酚类化合物发生非共价相互作用。在阴离子交换色谱过程中，这些相互作用被破坏，导致寡聚Ara h 1复合物解离成蛋白质三聚体。通过使用与Ara h 1同源的大豆蛋白β-伴大豆球蛋白的已知三维结构，在其三聚体结构的两个面上通过计算机模拟观察到富含脯氨酸的区域，这些区域在Ara h 1中是保守的。这些富含脯氨酸的区域可以解释原花青素与Ara h 1的结合以及多个Ara h 1三聚体复合物的形成。向三聚体Ara h 1和β-伴大豆球蛋白中添加花生原花青素会导致形成可溶性寡聚蛋白复合物，这一观察结果支持了上述观点。结构相关的豆球蛋白在蛋白质两侧不含有此类富含脯氨酸的区域，并且已证明原花青素对来自花生和大豆的豆球蛋白（分别为花生过敏原Ara h 3和大豆球蛋白）的亲和力较低。以寡聚复合物形式存在的Ara h 1被认为是人类摄入的过敏原的代表性形式。
