Schönherr R, Hilger M, Broer S, Benz R, Braun V
Lehrstuhl für Mikrobiologie II, Universität Tübingen, Germany.
Eur J Biochem. 1994 Jul 15;223(2):655-63. doi: 10.1111/j.1432-1033.1994.tb19038.x.
Pore formation by hemolysin (ShlA) of Serratia marcescens was studied in erythrocytes and in artificial lipid bilayer membranes. The results with erythrocytes demonstrated that hemolysin pores varied in size. In erythrocyte membranes with reduced fluidity (0 degrees C), the toxin formed small pores with diameter 1-1.5 nm. In fluid membranes (above 20 degrees C), hemolysin pores with larger diameters (approximately 2.5-3.0 nm) were observed, which may be caused by association of ShlA monomers into oligomers. Comparison of the channels formed by Staphylococcus aureus alpha-toxin with channels formed by ShlA indicated a slightly smaller pore diameter of ShlA pores. Analysis of ShlA in artificial lipid bilayers showed the formation of pores with a broad distribution of single channel conductances, suggesting variable sizes of the ShlA pore. The lower limit for the pore diameter was approximately 1.0 nm. The ShlA pores did not exhibit pronounced ion selectivity nor voltage dependence, supporting the presence of a large water-filled pore.
对粘质沙雷氏菌溶血素（ShlA）在红细胞和人工脂质双分子层膜中形成孔道的情况进行了研究。红细胞实验结果表明，溶血素孔道大小各异。在流动性降低的红细胞膜（0摄氏度）中，毒素形成直径为1 - 1.5纳米的小孔道。在流动性较好的膜（20摄氏度以上）中，观察到直径较大（约2.5 - 3.0纳米）的溶血素孔道，这可能是由于ShlA单体聚合成寡聚体所致。将金黄色葡萄球菌α毒素形成的通道与ShlA形成的通道进行比较，结果表明ShlA孔道的孔径略小。在人工脂质双分子层中对ShlA的分析显示，形成的孔道具有广泛分布的单通道电导，这表明ShlA孔道大小不一。孔径下限约为1.0纳米。ShlA孔道未表现出明显的离子选择性和电压依赖性，这支持了存在一个大的充满水的孔道的观点。
