INTERACTION OF CONCANAVALIN-A WITH MODEL SUBSTRATES
INTERACTION OF CONCANAVALIN-A WITH MODEL SUBSTRATES
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DOI：
10.1111/j.1749-6632.1974.tb53040.x
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发表时间：
1974-01-01
影响因子：
5.2
通讯作者：
MISAKI, A
中科院分区：
文献类型：
--
作者：
GOLDSTEIN, IJ;REICHERT, CM;MISAKI, A
在过去的几年中，豆豆蛋白A已成为最广为人知和深入研究的植物血凝素。这种兴趣很大程度上源于发现这种凝集素具有几个显著的生物学特性。除了作为血凝素、“结构探针”和有丝分裂原的作用外，“-”刀豆蛋白a已被证明可恢复转化成纤维细胞的正常生长模式，O可作为抗癌剂，并可区分恶性细胞和正常细胞。’~豆豆蛋白A已被测序11 - 11，并在2.0、2.4和4a水平上确定了其三维x射线结构。11~ 17对该蛋白的溶液性质也进行了研究，x射线分析的结果与分析性超离心的结果基本一致。Fi和平衡透析研究。已经出现的图片是由分子量为27000的亚基组成的金属蛋白；每个亚基具有一个糖结合位点。在pH 5.5及以下，蛋白质以二聚体的形式存在，分子量为54,000。在pH高于5.5时，蛋白质二聚体开始聚集，形成具有四个结合位点的四聚体。由Sumner和Howell首先指出的刀豆蛋白a -大分子相互作用与抗体-抗原系统之间的类比，已经被几位研究人员评论。事实上，刀豆蛋白a -碳水化合物的相互作用已经通过多种免疫化学技术进行了研究：Landsteiner半素的定量沉淀。I1和平衡透析测量。为了解释豆豆蛋白A与特定的支链大分子之间的沉淀反应，我们假设了一种链端机制33~ 37。m.-(*)例如，ad -葡聚糖。甘露聚糖和8- d -果聚糖)。如下所示，这种概括需要修改。链端机构的模型如图1所示。刀豆蛋白A被描述为具有四个结合位点的四聚体蛋白，每个位点都能够与多糖或糖蛋白链末端的特定末端糖基残基相互作用。由于只有中性糖与豆豆蛋白A发生反应，因此假设氢键可能在结合现象中起重要作用。我:……我。15 . .通过使用单糖及其衍生物作为魔豆蛋白a -葡聚糖相互作用的抑制剂，已经有可能确定一个分子必须具有的构型特征，以便与魔豆蛋白a结合。在某些情况下，这是可能的
During the last few years concanavalin A has become the most widely known and intensively investigated phytohemagglutinin. Much of this interest stems from the discovery that this lectin possesses several remarkable biological properties. In addition to its role as a hemagglutinin,'a structural probe,'and a mitogen,"-" concanavalin A has been shown to restore normal growth patterns to transformed fibroblasts, O to serve as an anticarcinogenic agent,'and to distinguish between malignant and normal cells.'~ concanavalin A has been sequenced l1-I1 and its three-dimensional x-ray structure has been determined at the 2.0, 2.4, and 4 A levels. 11~ 17 The solution properties of this protein have also been studied in some The results of the x-ray analysis are in general accord with analytical ultracentrifugation 1 6-w 2?.? fi and equilibrium dialysis studies."'. The picture that has emerged is of a metalloprotein composed of subunits with a molecular weight of 27,000; each subunit possesses one sugar-binding site. At pH 5.5 and below, the protein exists as a dimer, molecular weight 54,000. Above pH 5.5 the protein dimers begin to aggregate, forming a tetramer with four binding sites. The analogy between concanavalin A-macromolecule interaction and the antibody-antigen system, first noted by Sumner and Howell, l has been commented upon by several inve~ tigators.~ l-~~ In fact, the concanavalin A-carbohydrate interaction has been studied by means of a variety of immunochemical techniques: the quantitative precipitin the Landsteiner haptene. I1 and equilibrium dialysis measurements.'::. Lit A chain-end mechanism was postulated to account for the precipitation reaction between concanavalin A and certain specific, branched macromolecules, 33~ 37.. m.-(*(for example, aD-glucans. aD-mannans and 8-D-fructans). As indicated below, this generalization requires modification. A model of the chain-end mechanism is shown in FIGURE 1. Concanavalin A is depicted as a tetrameric protein with four combining sites, each capable of interacting with specific, terminal glycosyl residues of polysaccharide or glycoprotein chain ends. Since only neutral saccharides react with concanavalin A, it has been postulated that hydrogen bonding probably plays an important role in the binding phenome-, on.: i:.. &I. 15.. II: Through the use of simple sugars and their derivatives as inhibitors of the concanavalin A-dextran interaction, it has been possible to ascertain the configurational features that a molecule must possess in order to bind to concanavalin A. In some instances it has been possible to