Morel N, Thieffry M, Manaranche R
J Cell Biol. 1983 Dec;97(6):1737-44. doi: 10.1083/jcb.97.6.1737.
The crude extract of venom glands of the polychaete annelid Glycera convoluta triggers a large Ca2+-dependent acetylcholine release from both frog motor nerve terminals and Torpedo electric organ synaptosomes. This extract was partially purified by Concanavalin A affinity chromatography. The biological activity was correlated in both preparations to a 300,000-dalton band, as shown by gel electrophoresis. This confirmed previous determinations obtained with chromatographic methods. This glycoprotein binds to presynaptic but not postsynaptic plasma membranes isolated from Torpedo electric organ. Pretreatment of intact synaptosomes by pronase abolished both the binding and the venom-induced acetylcholine release without impairing the high K+-induced acetylcholine release. Pretreatment of nerve terminal membranes by Concanavalin A similarly prevented the binding and the biological response. Binding to Torpedo membranes was still observed in the presence of EGTA. An antiserum directed to venom glycoproteins inhibited the neurotoxin so we could directly follow its binding to the presynaptic membrane. Glycera convoluta neurotoxin has to bind to a ectocellularly oriented protein of the presynaptic terminal to induce transmitter release.
多毛纲环节动物旋鳃甘油虫毒腺的粗提物可引发青蛙运动神经末梢和电鳐电器官突触体中大量依赖钙离子的乙酰胆碱释放。该提取物通过伴刀豆球蛋白A亲和层析进行了部分纯化。凝胶电泳显示，两种制剂中的生物活性均与一条300,000道尔顿的条带相关。这证实了先前通过色谱法获得的测定结果。这种糖蛋白与从电鳐电器官分离的突触前而非突触后质膜结合。用链霉蛋白酶预处理完整的突触体可消除结合以及毒液诱导的乙酰胆碱释放，而不会损害高钾诱导的乙酰胆碱释放。用伴刀豆球蛋白A预处理神经末梢膜同样可阻止结合和生物反应。在存在乙二醇双四乙酸（EGTA）的情况下，仍可观察到与电鳐膜的结合。针对毒液糖蛋白的抗血清可抑制神经毒素，因此我们可以直接追踪其与突触前膜的结合。旋鳃甘油虫神经毒素必须与突触前末梢细胞外定向的蛋白质结合才能诱导递质释放。
