Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria.
CERM & Department of Chemistry, University of Florence, Florence, Italy.
Sci Rep. 2019 Feb 14;9(1):2007. doi: 10.1038/s41598-019-38563-1.
Plant non-specific lipid transfer proteins type 1 (nsLTP1) are small basic proteins with a hydrophobic cavity able to host a number of different ligands: i.e. fatty acids, fatty acyl-CoA, phospholipids, glycolipids, and hydroxylated fatty acids. However, ligand binding specificity differs among nsLTPs. Within this protein family, Jug r 3 from walnut has been identified as a major allergen. So far, data on the structural characterization of Jug r 3 and its lipid binding capacity are lacking. We report the results from a fluorescence-based ligand-binding assay and ligand-based NMR experiments, to study the binding interactions between Jug r 3 and the 18-carbon monounsaturated oleic acid. Furthermore, protein-based NMR experiments were employed to detect the oleate binding site of Jug r 3. The NMR data were used to dock the oleate molecule into the structural model of Jug r 3. Finally, the impact of the interaction on the allergenic potential of Jug r 3 was investigated by IgE ELISA with 6 sera from walnut allergic patients. Our data corroborate the hypothesis of direct impact of food-derived matrix on the IgE reactivity of nsLTPs.
植物非特异性脂质转移蛋白 1（nsLTP1）是一类小分子碱性蛋白，具有疏水性空腔，能够容纳多种不同的配体：如脂肪酸、脂肪酸辅酶 A、磷脂、糖脂和羟基脂肪酸。然而，nsLTP 之间的配体结合特异性存在差异。在该蛋白家族中，胡桃中的 Jug r 3 被鉴定为主要过敏原。迄今为止，关于 Jug r 3 的结构特征及其脂质结合能力的数据尚不清楚。我们报告了基于荧光的配体结合分析和基于配体的 NMR 实验的结果，以研究 Jug r 3 与 18 碳单不饱和油酸之间的结合相互作用。此外，还采用基于蛋白质的 NMR 实验来检测 Jug r 3 的油酸结合位点。NMR 数据用于将油酸分子对接进 Jug r 3 的结构模型中。最后，通过 6 份来自胡桃过敏患者的血清进行 IgE ELISA 实验，研究了这种相互作用对 Jug r 3 过敏原性的影响。我们的数据证实了食物基质直接影响 nsLTPs 的 IgE 反应性的假设。
