皖南尖吻蝮蛇中11个C型凝集素类似蛋白亚单位的cDNA克隆和序列分析

通过放射性标记DNA探针筛选和PCR克隆筛选 ,从皖南尖吻蝮蛇毒腺的λgt11cDNA文库中 ,克隆得到了 11个编码C型凝集素类似蛋白亚单位的cDNA .其中 2个克隆分别含有编码an tithrombinA的A链和B链的序列 .另外 6个则含有编码如下肽链的序列 :antithrombinC的A链和B链、agkisacutacin的A链和B链、抗凝血因素的A链和B链 ,其它 3个克隆含有编码未知蛋白质的序列 .有趣的是 ,在编码AntithrombinC的序列中 ,每条链中除了含有 7个与所有C型凝集素类似蛋白位置一致的Cys外 ,在B链上还含有一个额外的Cys3;2条B链上的Cys3可能形成一对新的链间二硫键 .氨基酸序列的比较及进化分析显示 ,C型凝集素类似蛋白B链起源于一个单系类群 ,A链至少有 4个进化起源

Cloning and Sequencing of Eleven cDNAs of C-type Lectin-like Protein Subunits from Agkistrodon Acutus

Eleven different cDNAs encoding C\|type lectin\|like protein subunits were screened,isolated and cloned from the cDNA library of Agkistrodon acutus venom gland by radiolabled DNA probe and polymerase chain reaction.Among them,two contain the sequences encoding A and B chain of antithrombin A respectively,and six encode A or B chains of antithrombin C,agkisacutacin and anticoagulant factor. Interestingly,besides the common positions of seven systeines to all C\|type lectin\|like proteins,antithrombin C contains an additional cysteine in the B chain.Two cysteines of two B chains may be involved in a novel interchain disulfide bridge.The putative proteins encoded by other three clones have not been found in snake venoms so far.