van Boxtel Evelien L, van Beers Miranda M C, Koppelman Stef J, van den Broek Lambertus A M, Gruppen Harry
Laboratory of Food Chemistry, Wageningen University, PO Box 8129, 6700 EV Wageningen, The Netherlands.
J Agric Food Chem. 2006 Sep 20;54(19):7180-6. doi: 10.1021/jf061433+.
Ara h 1, a major peanut allergen, is known as a stable trimeric protein. Nevertheless, upon purification of native Ara h 1 from peanuts using only size exclusion chromatography, the allergen appeared to exist in an oligomeric structure, rather than as a trimeric structure. The oligomeric structure was independent of the salt concentration applied. Subjecting the allergen to anion exchange chromatography induced the allergen to dissociate into trimers. Ammonium sulfate precipitation did not bring about any structural changes, whereas exposing the allergen to hydrophobic interaction chromatography caused it to partly dissociate into trimers, with increasing amounts of trimers at higher ionic strengths. The (partial) dissociation into trimers led to a change in the tertiary structure of the monomeric subunits of the allergen, with the monomers in Ara h 1 oligomers having a more compact tertiary structure compared with the monomers in Ara h 1 trimers. As structural characteristics are important for a protein's allergenicity, this finding may imply a different allergenicity for Ara h 1 than previously described.
Ara h 1是一种主要的花生过敏原，是一种稳定的三聚体蛋白。然而，仅使用尺寸排阻色谱法从花生中纯化天然Ara h 1时，该过敏原似乎以寡聚体结构存在，而非三聚体结构。该寡聚体结构与所应用的盐浓度无关。使该过敏原进行阴离子交换色谱会导致其解离成三聚体。硫酸铵沉淀未引起任何结构变化，而将该过敏原进行疏水相互作用色谱会使其部分解离成三聚体，且在较高离子强度下三聚体数量增加。（部分）解离成三聚体会导致该过敏原单体亚基的三级结构发生变化，与Ara h 1三聚体中的单体相比，Ara h 1寡聚体中的单体具有更紧凑的三级结构。由于结构特征对蛋白质的致敏性很重要，这一发现可能意味着Ara h 1的致敏性与先前描述的不同。
