ION-CONDUCTING CHANNELS PRODUCED BY BOTULINUM TOXIN IN PLANAR LIPID-MEMBRANES
ION-CONDUCTING CHANNELS PRODUCED BY BOTULINUM TOXIN IN PLANAR LIPID-MEMBRANES
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DOI：
10.1021/bi00358a020
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发表时间：
1986-05-20
期刊：
影响因子：
2.9
通讯作者：
MIDDLEBROOK, JL
中科院分区：
文献类型：
--
作者：
DONOVAN, JJ;MIDDLEBROOK, JL
通过测定肉毒杆菌神经毒素形成离子传导通道的能力，研究了肉毒杆菌神经毒素与平面脂膜的相互作用。通道的形成依赖于pH。在生理pH下，Botx不形成通道，而在pH 6.6时，该毒素在0.1M的氯化钠溶液中形成单位电导为12ps的通道。通道形成速率随pH的降低而增加，在pH 6.1时达到最大值，然后在较低的pH值下降低。这些通道一旦形成，在整个实验过程中都是膜上的永久实体，并在打开和关闭状态之间波动。通道形成的速率依赖于毒素浓度的平方，表明聚集步骤参与了通道的形成。这些数据与Botx通过内吞作用进入细胞，然后在低pH值下释放到细胞质中的假设一致。
The interaction of botulinum neurotoxin (Botx) with planar lipid membranes was studied by measuring the ability of the toxin to form ion-conducting channels. Channel formation was pH dependent. At physiological pH, Botx formed no channels, whereas at pH 6.6, the toxin formed channels with a unit conductance of 12 pS in 0.1 M NaCl. The rate of channel formation increased with decreasing pH, reaching a maximum at pH 6.1, and then decreased at lower values of pH. The channels, once formed, were permanent entities in the membrane throughout the course of an experiment and fluctuated between an open and a closed state. The rate of channel formation depended upon the square of the toxin concentration, suggesting an aggregation step is involved in channel formation. The data were consistent with the hypothesis that Botx enters cells through endocytosis, followed by its release into the cytoplasm at low pH.