Patthy L
Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest.
Mol Immunol. 1989 Dec;26(12):1151-4. doi: 10.1016/0161-5890(89)90059-x.
The major protein constituent of eosinophilic leukocyte granules is a cytotoxic protein that plays a key role in antiparasitic defence mechanisms and immune hypersensitivity reactions. We show here that the protein is homologous with animal lectins; it exhibits greatest similarity to the lectin domain of the low-affinity IgE receptor of lymphocytes. On the basis of homology with lectins the disulphide bond pattern of the protein is predicted. It is proposed that certain cysteines unique to major basic protein are on the surface of the molecule and are involved in forming disulphide-bonded polymers. Homology with IgE receptor raises the possibility that major basic protein may also bind to IgE antibodies. Such an interaction could provide an efficient way of targeting the cytotoxic protein to parasites and allergens recognized by IgE antibodies.
嗜酸性粒细胞颗粒的主要蛋白质成分是一种细胞毒性蛋白，它在抗寄生虫防御机制和免疫超敏反应中起关键作用。我们在此表明，该蛋白与动物凝集素同源；它与淋巴细胞低亲和力IgE受体的凝集素结构域表现出最大的相似性。基于与凝集素的同源性，预测了该蛋白的二硫键模式。有人提出，主要碱性蛋白特有的某些半胱氨酸位于分子表面，并参与形成二硫键连接的聚合物。与IgE受体的同源性增加了主要碱性蛋白也可能与IgE抗体结合的可能性。这种相互作用可以提供一种将细胞毒性蛋白靶向IgE抗体识别的寄生虫和过敏原的有效方式。
