Grishin E V
Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow.
Toxicon. 1998 Nov;36(11):1693-701. doi: 10.1016/s0041-0101(98)00162-7.
The venom of the black widow spider Latrodectus mactans tredisimguttatus was found to contain a family of high molecular weight toxic proteins inducing a sharp increase in transmitter secretion from the affected nerve endings, which are highly specific for vertebrates, or for insects, or for crustaceans. Along with the known alpha-latrotoxin, five latroinsectotoxins affecting the neurotransmitter release from presynaptic endings of insects and one latrocrustatoxin active only for crustaceans were isolated and studied in detail. Alpha-latrotoxin provokes a massive transmitter release from different nerve endings of vertebrates, whereas other toxins increase the secretion process either in insects or crustaceans. The cDNAs encoding the putative alpha-latrotoxin and two latroinsectotoxins (alpha-latroinsectotoxin and delta-latroinsectotoxin) precursors were cloned and sequenced. These toxins are polypeptides of about 1000 amino acids and share a high level of amino acid identity. Analysis of amino acid sequences of the three toxins reveals the central regions being almost entirely composed of series of ankyrin-like repeats. Taking into account the size and multifunctional properties of latrotoxin its molecule can be divided into several functional domains. Immunochemical experiments indicated the presence in the alpha-latrotoxin molecule of distinguishable functional domains responsible for ionophoric and secretogenic actions. The highly purified preparation of alpha-latrotoxin was shown to contain an additional component, a low molecular weight protein structurally related to crustacean hyperglycemic hormones. Several attempts were made to characterize and isolate alpha-latrotoxin receptor components. The existence of Ca-dependent and Ca-independent binding proteins was found in the presynaptic membrane preparations.
人们发现，南方黑寡妇蜘蛛（Latrodectus mactans tredisimguttatus）的毒液含有一族高分子量毒性蛋白，这些蛋白会使受影响神经末梢的递质分泌急剧增加，它们对脊椎动物、昆虫或甲壳类动物具有高度特异性。除了已知的α-蛛毒素外，还分离并详细研究了5种影响昆虫突触前末梢神经递质释放的蛛昆虫毒素以及1种仅对甲壳类动物有活性的蛛甲壳毒素。α-蛛毒素可引发脊椎动物不同神经末梢大量释放递质，而其他毒素则可增加昆虫或甲壳类动物的分泌过程。编码假定的α-蛛毒素和两种蛛昆虫毒素（α-蛛昆虫毒素和δ-蛛昆虫毒素）前体的cDNA被克隆并测序。这些毒素是约1000个氨基酸的多肽，氨基酸同一性水平很高。对这三种毒素的氨基酸序列分析表明，其中心区域几乎完全由一系列锚蛋白样重复序列组成。考虑到蛛毒素的大小和多功能特性，其分子可分为几个功能域。免疫化学实验表明，α-蛛毒素分子中存在负责离子载体和促分泌作用的可区分功能域。高纯度的α-蛛毒素制剂显示含有一种额外成分，即一种与甲壳类动物高血糖激素结构相关的低分子量蛋白。人们进行了多次尝试来表征和分离α-蛛毒素受体成分。在突触前膜制剂中发现了钙依赖性和钙非依赖性结合蛋白的存在。
