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Study on the structure of marine invertebrate lectins and their cell membrane-damaging action

海洋无脊椎动物凝集素的结构及其细胞膜损伤作用研究

基本信息

批准号：
10660094
负责人：
HATAKEYAMA Tomomitsu
金额：
$ 2.11万
依托单位：
Nagasaki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10660094/
关键词：
lectin calcium marine invertebrate chemical modification hemolysin toxin protein conjugate リポソーム糖脂質

项目摘要

Structure and function of the carbohydrate-binding proteins (lectins) from a sea cucumber (Cucumaria echinata) and other marine invertebrates were investigated. Among four CaィイD12+ィエD1-dependent lectins from C. echinata, a galactose/N-acetylgalactosamine-specific lectin, CEL-III, exhibited strong hemolytic activity toward human and rabbit erythrocytes by forming ion-permeable pores in the cell membrane. In order to identify CEL-III receptor, membrane lipids were purified from human erythrocytes, and were assessed for their CEL-III receptor ability. As a result, glycolipids containing β-galactose or N-acetylgalactosamine at their nonreducing ends showed high affinity as well as effective receptor ability for CEL-III. Furthermore, it was also suggested that the receptor ability depends not only on the affinity for CEL-III, but also on the structure or length of the carbohydrate chains. On the other hand, chemical modification studies revealed that amino and carboxyl groups of CEL-III are involved in the hemolytic mechanism. Although modification of amino groups markedly reduced only hemolytic activity, modification of carboxyl groups led to decrease in both hemolytic and hemagglutinating activity of CEL-III. This suggests that some carboxyl groups are involved in one of two carbohydrate-binding sites of CEL-III. As a model of such a hemolytic lectin, novel protein conjugates consisting of lectins and amphiphilic α-helical peptides were also prepared. Since they exhibited hemolytic activity, depending on the carbohydrate-binding nature, these conjugates were suggested to interact with cell membrane after binding to the surface carbohydrate chains.

研究人员对海参（Cucumaria echinata）和其他海洋无脊椎动物的碳水化合物结合蛋白（凝集素）的结构和功能进行了研究。在来自 C. echinata 的四种 CaィイD12+ィD1 依赖性凝集素中，一种半乳糖/N-乙酰半乳糖胺特异性凝集素 CEL-III 通过在细胞膜上形成离子渗透孔，对人和兔红细胞表现出强烈的溶血活性。为了鉴定 CEL-III 受体，从人红细胞中纯化膜脂，并评估其 CEL-III 受体能力。结果，非还原端含有β-半乳糖或N-乙酰半乳糖胺的糖脂对CEL-III表现出高亲和力以及有效的受体能力。此外，还表明受体能力不仅取决于对CEL-III的亲和力，还取决于碳水化合物链的结构或长度。另一方面，化学修饰研究表明CEL-III的氨基和羧基参与溶血机制。虽然氨基的修饰仅显着降低了溶血活性，但羧基的修饰导致CEL-III的溶血活性和血凝活性均降低。这表明一些羧基参与了 CEL-III 的两个碳水化合物结合位点之一。作为这种溶血凝集素的模型，还制备了由凝集素和两亲性α-螺旋肽组成的新型蛋白质缀合物。由于它们表现出溶血活性，这取决于碳水化合物的结合性质，因此建议这些缀合物在与表面碳水化合物链结合后与细胞膜相互作用。