Generation of a membrane-bound, oligomerized pre-pore complex is necessary for pore formation by Clostridium septicum alpha toxin.
Generation of a membrane-bound, oligomerized pre-pore complex is necessary for pore formation by Clostridium septicum alpha toxin.
复制标题
膜结合的寡聚化前孔复合物的产生对于败血梭状芽胞杆菌α毒素形成孔是必要的。
DOI：
10.1046/j.1365-2958.1997.d01-1876.x
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发表时间：
1997
影响因子：
3.6
通讯作者：
Tweten,RK
中科院分区：
文献类型：
--
作者：
Sellman,BR;Kagan,BL;Tweten,RK
低温抑制α毒素的细胞溶解活性有助于识别该毒素的细胞溶解机制中的一个重要步骤。当在不同温度下测量红细胞上的α毒素依赖性溶血时，很明显，在温度≤15°C时，溶血速率受到显着抑制，在4°C时很少或没有发生溶血。 α 毒素似乎在 4°C 和 37°C 下以相似的动力学结合到红细胞膜上并在其上寡聚化。 4°C 和 37°C 下这两个过程的细微差异不能解释低温下细胞溶解活性的丧失。在 4°C 时，α 毒素既不会刺激红细胞释放钾，也不会在平面膜上形成孔。相反，在温度≥25°C 时，这两个过程都快速进行。渗透压稳定的红细胞中打开的孔不能通过低温关闭。因此，低温似乎可以防止低聚复合物在膜中形成孔。这些数据支持这样的假设：在脂质双层中形成孔之前，α毒素寡聚成膜结合的前孔复合物。
Low‐temperature inhibition of the cytolytic activity of alpha toxin has facilitated the identification of an important step in the cytolytic mechanism of this toxin. When alpha toxin‐dependent haemolysis was measured on erythrocytes at various temperatures it was clear that at temperatures ≤15°C the haemolysis rate was significantly inhibited with little or no haemolysis occurring at 4°C. Alpha toxin appeared to bind to and oligomerize on erythrocyte membranes with similar kinetics at 4°C and 37°C. The slight differences in these two processes at 4°C and 37°C could not account for the loss of cytolytic activity at low temperature. At 4°C alpha toxin neither stimulated potassium release from erythrocytes nor formed pores in planar membranes. In contrast, at temperatures ≥25°C both processes proceeded rapidly. Pores that were opened in osmotically stabilized erythrocytes could not be closed by low temperature. Therefore, low temperature appeared to prevent the oligomerized complex from forming a pore in the membrane. These data support the hypothesis that alpha toxin oligomerizes into a membrane‐bound, pre‐pore complex prior to formation of a pore in a lipid bilayer.