Physical-chemical characterization and carbohydrate-binding activity of the A and B subunits of the Bandeiraea simplificolia I isolectins.
Physical-chemical characterization and carbohydrate-binding activity of the A and B subunits of the Bandeiraea simplificolia I isolectins.
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Bandeiraea simplificolia I 同凝素 A 和 B 亚基的物理化学特征和碳水化合物结合活性。
DOI：
10.1021/bi00589a030
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发表时间：
1979
期刊：
影响因子：
2.9
通讯作者：
I J Goldstein
中科院分区：
文献类型：
--
作者：
L. A. Murphy;I J Goldstein
单根带属植物种子分离素包括一个四聚体α - d -半乳糖酰基结合糖蛋白家族，由不同亚基a和B的不同组合组成。a亚基（Aa、Ab、Ac、Ad和Ae）和B亚基（Ba、Bb、Bc、Bd和Be）的亚型因种子而异（例如，一些种子只含有B亚基，另一些只含有a亚基），Ac和Bc亚型在天然的分离素混合物中占主导地位。二维琼脂凝胶扩散研究表明，除了共同的结构特征外，每个亚基都含有自己独特的抗原决定因子。虽然A亚基和B亚基的氨基酸组成非常相似，但它们在一个方面有明显的不同：B亚基有一个蛋氨酸残基，而A亚基不含蛋氨酸。两种亚基的中性碳水化合物含量是相同的。研究了生物聚合物和合成糖蛋白沉淀A4和B4的能力，以及糖和低聚糖抑制沉淀形成的能力。在这些研究的基础上，我们认为α - d - galnacp和α - d - galnacp的C-3和C-4羟基以及α - d - galnacp的A和B亚基的氢原子之间分别发生了氢键。
Bandeiraea simplicifolia I plant seed isolectins comprise a family of tetrameric alpha-D-galactopyranosyl-binding glycoproteins composed of various combinations of teo different kinds of subunits designated A and B. Subtypes of the A (Aa, Ab, Ac, Ad, and Ae) and B (Ba, Bb, Bc, Bd, and Be) subunits were demotypes varies from seed to seed (e.g., some seeds contain only B subunits, others only A subunits), subtypes Ac and Bc predominate in a natural mixture of the isolectins. Two-dimensional agar gel diffusion studies indicate that, in addition to common structural features, each subunit contains its own distinct antigenic determinants. Although the A and B subunits have closely similar amino acid compositions, they differ markedly in one respect: the B subunit has one methionine residue whereas the A subunit contains no methionine. The neutral carbohydrate content of both subunits is identical. The ability of biopolymers and synthetic glycoproteins to precipitate A4 and B4, as well as the capacity of sugars and oligosaccharides to inhibit precipitate formation, was examined. On the basis of these studies, it is suggested that hydrogen bonding occurs between the hydrogen atoms of the C-3 and C-4 hydroxyl groups of alpha-D-GalNAcp and alpha-D-galp units and the A and B subunits, respectively.