四个烙铁头蛇毒凝集素样蛋白基因的克隆与序列分析

Cloning and Sequence Analysis of cDNAs Encoding Four C-type Lectin-like Proteins from Snake Trimeresurus mucrosquamatus

摘要: 从烙铁头蛇(Trimeresurus mucrosquamatus)的毒腺中提取mRNA，利用RT-PCR进行体外扩增，获得凝集素样蛋白基因，克隆至PMD18－T载体中，筛选出4种凝集素样蛋白基因(命名为TML-1、TML-2、TML-3和TML-4)。由基因序列推导出的氨基酸序列表明：TML-1，2，3，4序列中均有CRD结构。序列同源性比较和Cys位点分析推测：TML-1和TML-2可能分别是类似于flavocetin-A的蛇毒凝集素样蛋白的α亚基和β亚基；TML-3可能类似于GPIb-bp的蛇毒凝集素样蛋白的α亚基，TML-4则可能是类似于Ⅸ/Ⅹ-bp的蛇毒凝集素样蛋白的β亚基。

Abstract: The total mRNA was prepared and purified from the venom glands of snake Trimer esurus mucrosquamatus.The cDNAs encoding C-type lectin-like proteins were amplified by RT-PCR and cloned into the PMD 18-T vectors.The positive clones encoding four C-type lectin-like proteins (TML-1,TML-2,TML-3 and TML-4) were selected and sequenced.Amino acid sequences of these proteins were deduced and each contains carbohydraterecognition domain (CRD).Homology comparison and cystein position analysis indicate that TML-1 and TML-2 might be the α and β subunits of a C-type lectin-like protein similar to flavocetin-A,TML-3 the α subunit of a C-type lectin-like protein similar to GPIb-bp,and TML-4 the β subunit of a C-type lectin-like protein similar to Ⅸ/Ⅹ-bp.