Moran O, Zegarra-Moran O, Virginio C, Gusmani L, Rottini G D
Settore di Biofisica, SISSA, Trieste, Italy.
FEMS Microbiol Immunol. 1992 Sep;5(1-3):63-9. doi: 10.1111/j.1574-6968.1992.tb05888.x.
The cytolytic toxin (CTox) produced by Gardnerella vaginalis is able to form voltage-dependent cationic channels when incorporated in lipid membranes (Moran et al. (1991) FEBS Lett. 283, 317-320). Osmotic protection experiments show that toxin incorporated in human erythrocytes forms pores between 18 A and 28 A in diameter. A hypothesis of pore formation as a primary event to produce cytolysis is proposed. The CTox activity increases when cells are depolarized by increasing the extracellular K+ concentration, probably reflecting the voltage dependent character of CTox formed channels. The cytolytic effect of the toxin was prevented by low temperatures and was a function of the extracellular Ca2+ concentration, suggesting a Ca2+ influx as part of the lytic mechanism. Binding of CTox to erythrocytes was dependent on external Ca2+ and was less temperature-dependent. Dose-response analysis suggests cooperativity of the toxin for the lytic activity, although no direct evidence of oligomerization has been found.
阴道加德纳菌产生的细胞溶解毒素（CTox）整合到脂质膜中时能够形成电压依赖性阳离子通道（Moran等人，(1991)《欧洲生物化学学会联合会快报》283, 317 - 320）。渗透保护实验表明，整合到人类红细胞中的毒素形成直径在18埃至28埃之间的孔。提出了孔形成是产生细胞溶解的主要事件的假说。当通过增加细胞外K⁺浓度使细胞去极化时，CTox活性增加，这可能反映了CTox形成的通道的电压依赖性特征。毒素的细胞溶解作用受低温抑制，并且是细胞外Ca²⁺浓度的函数，这表明Ca²⁺内流是溶解机制的一部分。CTox与红细胞的结合依赖于外部Ca²⁺，且温度依赖性较小。剂量反应分析表明毒素对溶解活性具有协同作用，尽管尚未发现寡聚化的直接证据。
