Zhang Xin, Yuan Jing Ming, Cui Xiao Dong, Wang Zhuan Hua
Key Laboratory for Chemical Biology and Molecular Engineering of the Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China.
J Agric Food Chem. 2008 Nov 26;56(22):10947-53. doi: 10.1021/jf801855a.
Buckwheat is generally regarded as a nutritionally rich food source. However, earlier studies prove that it also causes allergies to subjects. Allergenic proteins with a strong IgE-binding activity have been identified in common buckwheat (CB) and a 24 kDa allergen (rTBa) in tartary buckwheat (TB). The objective of this research was to clone and express a novel allergen in tartary buckwheat and to evaluate its structure and immunological activity. The 1773 bp full-length cDNA was amplified and cloned from the total RNA of TB by polymerase chain reaction (PCR) and rapid amplification of cDNA ends (RACE) methods. Its nucleotide sequence had high similarity with legume-like 13S storage protein mRNA in CB. The deduced amino acid sequence included a putative signal peptide and 18 fragments as its epitope sites. The predicted full-length TB allergen sequence was found to have two domains, and the recombinant protein reacted with sera from patients with positive IgE binding to buckwheat and had a lower binding ability than the recombinant TBa and recombinant TBb (C- and N-terminal amino acid sequence of TBt codes for protein). This fact suggests that full-length TB allergen may hydrolyze to two domains in vivo, decreasing the IgE-binding ability.
荞麦通常被视为一种营养丰富的食物来源。然而，早期研究证明它也会导致受试者过敏。在普通荞麦（CB）中已鉴定出具有强IgE结合活性的致敏蛋白，在苦荞（TB）中鉴定出一种24 kDa的过敏原（rTBa）。本研究的目的是克隆并表达苦荞中的一种新型过敏原，并评估其结构和免疫活性。通过聚合酶链反应（PCR）和cDNA末端快速扩增（RACE）方法，从苦荞的总RNA中扩增并克隆出1773 bp的全长cDNA。其核苷酸序列与普通荞麦中豆科植物样13S贮藏蛋白mRNA具有高度相似性。推导的氨基酸序列包括一个推定的信号肽和18个作为其表位位点的片段。预测的苦荞过敏原全长序列有两个结构域，重组蛋白与IgE结合苦荞呈阳性的患者血清发生反应，且结合能力低于重组TBa和重组TBb（TBt的C端和N端氨基酸序列编码蛋白质）。这一事实表明，苦荞过敏原全长在体内可能水解为两个结构域，从而降低IgE结合能力。
