Mellor I R, Thomas D H, Sansom M S
Department of Zoology, University of Nottingham, University Park, U.K.
Biochim Biophys Acta. 1988 Jul 21;942(2):280-94. doi: 10.1016/0005-2736(88)90030-2.
The delta-toxin of Staphylococcus aureus has been investigated in terms of its potential to form ion channels in planar lipid bilayers formed at the tip of patch electrodes. Channel formation has been shown to occur for delta-toxin concentrations in the range 0.1 to 2.0 microM. In 0.5 M KCl, two major classes of channels were seen--'small' with conductances of 70-100 pS, and 'large' with a conductance of approx. 450 pS. Current-voltage relationships for lipid bilayers containing several delta-toxin channels revealed both voltage-dependent and independent components to channel gating. Reversal potential measurements showed the channels to be cation selective. In the presence of 3.0 M KCl, the channel gating kinetics were complex, with multiple open and closed states. The results are interpreted in terms of a model for the channel consisting of a hexameric cluster of alpha-helical delta-toxin molecules.
已针对金黄色葡萄球菌的δ-毒素在膜片电极尖端形成的平面脂质双层中形成离子通道的潜力进行了研究。已表明，当δ-毒素浓度在0.1至2.0微摩尔范围内时会形成通道。在0.5M氯化钾中，观察到两类主要通道——电导为70 - 100皮安的“小”通道和电导约为450皮安的“大”通道。含有多个δ-毒素通道的脂质双层的电流-电压关系显示，通道门控存在电压依赖性和非依赖性成分。反转电位测量表明这些通道具有阳离子选择性。在3.0M氯化钾存在的情况下，通道门控动力学很复杂，存在多个开放和关闭状态。这些结果根据由α-螺旋δ-毒素分子的六聚体簇组成的通道模型进行了解释。
