拟南芥IQM2 cDNA 的克隆与生物信息学分析

拟南芥IQM2由At3g13600编码,是IQM家族的第二个成员,但在各种分子生物学相关的文献和数据库中都找不到其cDNA序列。本研究采用RACE和RT-PCR技术,克隆得到拟南芥IQM2基因的全长cDNA序列。该cDNA长2245 bp,其开放阅读框长1818 bp,编码1个由605个氨基酸残基组成的多肽链。生物信息学分析表明,IQM2蛋白含有一个IQ基序,属于钙不依赖性钙调素结合蛋白;其N端与豌豆重金属诱导蛋白6（HMIP6）有较高的同源性,而IQ基序则分布在HMIP6结构域内部;其C端与栝楼天花粉蛋白（trichosanthin）N端具有较高的同源性。

Cloning and Bioinformatics Analysis of IQM2 cDNA from Arabidopsis

Arabidospsis IQM2,the second member of the IQM family,is encoded by At3g13600.Its cDNA sequence,however,can not be found in any molecular biology literature or database.Using RACE and RT-PCR methods,a 2245 bp long full-length cDNA of Arabidopsis IQM2 was cloned in this study.Its open reading frame（ORF） was 1818 bp long and encoded for a 605-amino-acid polypeptide.Bioinformatics analysis revealed that the polypeptide had an IQ motif and shared sequence homology with the pea heavy metal-induced protein 6A in its N-terminus and a ribosome inactivating protein,trichosanthin,in its C-terminus.The IQ motif located in the homologous region of the pea heavy metal-induced protein 6A.