MEMBRANE GLYCOPROTEIN RECEPTOR AND HOLE-FORMING PROPERTIES OF A CYTOLYTIC PROTEIN TOXIN
MEMBRANE GLYCOPROTEIN RECEPTOR AND HOLE-FORMING PROPERTIES OF A CYTOLYTIC PROTEIN TOXIN
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DOI：
10.1021/bi00536a029
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发表时间：
1982-01-01
期刊：
影响因子：
2.9
通讯作者：
BUCKLEY, JT
中科院分区：
文献类型：
--
作者：
HOWARD, SP;BUCKLEY, JT
溶气素是一种细胞溶解细菌外毒素，用Iodogen试剂进行了放射性碘化。天然蛋白和抗溶气素抗体可抑制标记毒素与大鼠红细胞的结合。毒素一旦结合，并不能通过添加大量过量的游离溶气素来清除。放射性毒素与不同物种的红细胞的结合与未标记毒素的溶血特异性平行。用胰酶处理大鼠红细胞，去除一种主要的膜糖蛋白，导致结合显著减少，而胰凝乳酶处理没有影响。结合被从这些细胞中分离的糖蛋白部分所抑制，但不被大鼠红细胞总糖脂制剂所抑制。溶血素导致红细胞上形成孔洞，通过测量标记的MW标志物的释放来确定孔洞的大小。溶气素可使人或大鼠红细胞释放高血糖素(Mw 3550)及小分子，而不释放甲氧基菊粉(Mw 5500)及大分子。溶气素还可引起大的单层脂泡释放葡萄糖。因此，一个特定的糖蛋白受体明显地促进了溶气素与红细胞膜的相互作用。结合之后是形成离散的孔或孔；这导致细胞通过胶体渗透过程破裂。
Aerolysin, a cytolytic bacterial exotoxin, was radioiodinated by using the Iodogen reagent. Binding of the labeled toxin to rat erythrocytes was inhibited by the native protein and by anti-aerolysin antibody. Toxin, once bound, was not removed by the addition of a large excess of free aerolysin. Binding of the radioactive toxin to erythrocytes of different species paralleled the hemolytic specificity of the unlabeled toxin. Pretreatment of the rat erythrocytes with trypsin, which removed a major membrane glycoprotein, resulted in a dramatic decrease in binding, whereas chymotrypsin treatment had no effect. Binding was inhibited by a glycoprotein fraction isolated from these cells but not by a total rat erythrocyte glycolipid preparation. Aerolysin caused the formation of holes in erythrocytes which were sized by measuring the release of labeled MW markers. Glucagon (MW 3550) and smaller molecules entrapped in human or rat erythrocytes were released by treatment with aerolysin, whereas methoxyinulin (MW 5500) and larger molecules were not. Aerolysin also caused the release of glucose from large unilamellar lipid vesicles. Thus, a specific glycoprotein receptor evidently facilitates the interaction of aerolysin with erythrocyte membranes. Binding is followed by the formation of discrete holes or pores; this results in cell rupture by a colloid-osmotic process.