Menestrina G, Mackman N, Holland I B, Bhakdi S
Department of Physics, University of Trento, Povo, Italy.
Biochim Biophys Acta. 1987 Nov 27;905(1):109-17. doi: 10.1016/0005-2736(87)90014-9.
The action of the 107 kDa hemolysin from Escherichia coli on planar lipid membranes was investigated. We report that a single toxin molecule can form a cation-selective, ion-permeable channel of large conductance in a planar phospholipid bilayer membrane. The conductance of the pore is proportional to that of the bulk solution, indicating that the channel is filled with water. A pore diameter of about 2 nm can be evaluated. The pore formation mechanism is voltage-dependent and essentially resembles that of pore-forming colicins; this implies that opening of the channel is dependent on transfer of an electrical charge through the membrane. We propose that the physiological effects of E. coli hemolysin result from its ability to form ion channels in the membrane of attacked cells, and show that there is quantitative agreement between the effects of this toxin on model membranes and its hemolytic properties.
研究了来自大肠杆菌的107 kDa溶血素对平面脂质膜的作用。我们报告，单个毒素分子可在平面磷脂双层膜中形成具有大电导的阳离子选择性、离子通透通道。孔的电导与本体溶液的电导成正比，表明通道充满水。可评估出约2 nm的孔径。孔形成机制是电压依赖性的，本质上类似于成孔的大肠杆菌素；这意味着通道的开放依赖于电荷通过膜的转移。我们提出，大肠杆菌溶血素的生理效应源于其在被攻击细胞的膜中形成离子通道的能力，并表明该毒素对模型膜的作用与其溶血特性之间存在定量一致性。
