Martin B M, Carbone E, Yatani A, Brown A M, Ramírez A N, Gurrola G B, Possani L D
National Institute of Mental Health, Molecular Neurogenetics Unit, Bethesda, MD 20892.
Toxicon. 1988;26(9):785-94. doi: 10.1016/0041-0101(88)90319-4.
The complete amino acid sequence of the major toxic component (II.20.3.4), named toxin 1, from the venom of the Mexican scorpion C. l. tecomanus is reported. The sequence (66 amino acids) was obtained by direct Edman degradation of reduced and alkylated toxin, followed by sequence determination of selected peptides separated after enzymatic cleavage with S. aureus V8 protease. In cultured chick dorsal root ganglion cells, 0.5 microM toxin 1 slowed down specifically the time course of Na+ current inactivation, while Ca2+ currents from the same preparation were little affected. In neonatal rat ventricular heart cells, toxin 1, at concentrations between 0.1 and 0.5 microM, reduced Na+ currents without changing the kinetics and Ca2+ currents were unaffected. Comparative analysis of the primary structure of this toxin with other scorpion toxins shows a high degree of similarity with the north American scorpion toxins. This analysis suggests that the 'fine tuning' of the molecular mechanism of action of these toxins is related to variations in the primary structure as well as to the type of membrane under study (tissue specificity).
报道了从墨西哥蝎子C. l. tecomanus毒液中分离出的主要毒性成分（II.20.3.4）即毒素1的完整氨基酸序列。该序列（66个氨基酸）通过对还原和烷基化的毒素进行直接埃德曼降解获得，随后对经金黄色葡萄球菌V8蛋白酶酶切后分离出的特定肽段进行序列测定。在培养的鸡背根神经节细胞中，0.5微摩尔的毒素1特异性地减缓了Na⁺电流失活的时间进程，而同一标本中的Ca²⁺电流几乎未受影响。在新生大鼠心室肌细胞中，浓度在0.1至0.5微摩尔之间的毒素1使Na⁺电流减小，而动力学未改变，Ca²⁺电流不受影响。将该毒素的一级结构与其他蝎子毒素进行比较分析表明，它与北美蝎子毒素具有高度相似性。该分析表明，这些毒素作用分子机制的“微调”与一级结构的变化以及所研究的膜类型（组织特异性）有关。
