Weller U, Taylor C F, Habermann E
Toxicon. 1986;24(11-12):1055-63. doi: 10.1016/0041-0101(86)90132-7.
The fragments BIIb and C of tetanus toxin, which contain its binding domain, were quantitatively compared with native toxin and a toxoid with respect to axonal transport from the gastrocnemius muscle to the spinal cord in rats. Against 125I-toxin, the dose-ascent curve of labelled toxoid was shifted by a factor of 3-5 to higher concentrations, whereas the ascent of the labelled binding fragments was at least 50-100 times less. The binding fragments also differed from tetanus toxin by their very low affinity to rat brain membranes buffered to pH 7.5 in saline, but were equivalent with the toxin in buffer of low molarity and low pH. We conclude that additional parts of the toxin molecule have to complement the binding domain for expression of the full binding and transport characteristics of the toxin.
破伤风毒素的BIIb和C片段包含其结合结构域，就大鼠腓肠肌到脊髓的轴突运输而言，对其与天然毒素和类毒素进行了定量比较。与125I标记的毒素相比，标记类毒素的剂量上升曲线向更高浓度偏移了3至5倍，而标记结合片段的上升幅度至少低50至100倍。结合片段与破伤风毒素的不同之处还在于，它们对盐溶液中pH值为7.5的大鼠脑膜亲和力极低，但在低摩尔浓度和低pH值的缓冲液中与毒素相当。我们得出结论，毒素分子的其他部分必须补充结合结构域，以表达毒素完整的结合和运输特性。
