【摘要】 东亚钳蝎 (ButhusmartensiiKarsch ,BmK)蝎毒素BmKBT(又名BmKabT)是一个在初级结构上相似于β类哺乳动物毒素和功能接近于α类哺乳动物毒素的Na+ 通道毒素 .基于从毒腺cDNA文库中筛选得到的全长BmKBT前体核苷酸序列设计引物 ,以蝎基因组总DNA为模板进行聚合酶链式反应 (PCR) ,将PCR产物克隆至T载体、测序 .序列分析表明 :在BmKBT信号肽编码区的 3′端的- 4位Gly密码子的第 1位与第 2位碱基中有 1个长 2 2 5nt的内含子 ,插入位点距离该基因的起始密码子 4 6nt ,AT含量为 78 7% ,其内含子可能的剪接分枝位点距离 3′剪接受体位点 4 7nt.内含子的大小及其基因组织结构分析表明 :BmKBT具有与α类哺乳动物毒素类似的基因组织结构 ,进一步说明BmKBT是一个介于α类和β类Na+ 通道毒素之间的中间型蝎毒素 ,可以作为研究蝎毒素分子进化的合适材料更多还原

【Abstract】 BmKBT is a toxic component purified from the venom of Chinese scorpion Buthus martensii Karsch (BmK), specially acting on Na + channel. Although it is structurally similar to β type Na + channel toxins, BmKBT is functionally similar to α type Na + channel toxins. Base on the known sequence of BmKBT isolated from the cDNA library of the venom gland, genomic BmKBT was cloned by PCR method. Sequence analysis of genomic BmKBT shows that BmKBT has an intron of 225 base pairs located at the end of the signal peptide encoding region. The intron of BmKBT is similar to the α type sodium ion channel toxins in the size, the location and the sequence consensus of the 5′splice donor, a putative branch point distance 47 base pairs upstream of the 3′splice receptor. Combining with the function of BmKBT, the genomic organization of BmKBT indicates that it is a membership between α and β type sodium ion channel toxin, which might serve as a useful matter to research evolution of the scorpion venom gene.更多还原