中文摘要：

【目的】克隆梨小食心虫（Grapholitamolesta）普通气味结合蛋白2（GmolGOBP2）的全长cDNA序列并进行原核表达，为研究该蛋白在梨小食心虫化学感受系统中的作用奠定基础。【方法】利用RTPCR和RACE技术克隆GmolGOBP2的全长cDNA序列，并使用原核表达载体pET-32a在大肠杆菌BL21（DE3）中进行表达，用SDS-PAGE和Westernblot检测其表达情况。【结果】GmolGOBP2的cDNA全长序列为637bp（GenBank登录号：JN857940），开放性阅读框长度为483bp，编码161个氨基酸残基，成熟蛋白分子质量为15．98ku，等电点为4．85。GmolGOBP2预测蛋白的N末端具20个氨基酸残基组成的信号肽序列，并且氨基酸序列中具有6个保守半胱氨酸的典型气味结合蛋白家族标志。将GmolGOBP2编码序列重组到表达载体pET-32a中，转人大肠杆菌BL21（DE3）进行原核表达，SDS-PAGE和Westernblot检测结果显示，梨小食心虫普通气味结合蛋白基因在大肠杆菌中成功地表达出分子质量约为32ku的融合蛋白，与预测的融合蛋白分子质量大小一致。【结论】克隆并原核表达了GmolGOBP2的cDNA序列，可用于研究该蛋白分子结构及其在化学感受系统中的功能。

英文摘要：

[Objective] Cloning and prokaryotic expression of a novel cDNA encoding the general odor- ant binding protein 2 （GOBP2） from the oriental fruit moth Grapholita molesta was conducted. [Method] The full-length cDNA encoding GOBP2 isolated from GraphoLita rnolesta by reverse transcription-polymer- ase chain reaction （RT-PCR） and rapid amplification of cDNA ends-PCR （RACE-PCR） was named as GmolGOBP2. It was then constructed into the expression vector pET-32a and expressed in Escherichia coli BL21 （DE3）. [Result] The full length cDNA of GmolGOBP2 was 637 bp （GenBank accession no. JN857940） ,containing a 483 bp open reading frame with 161 amino acids. The deduced molecular weight （MW） was 15. 98 ku and the PI was 4.85. Protein signature analysis indicated that the deduced Gmol- GOBP2 contained an N-terminal signal sequence of 20 amino acids. The GmolGOBP2 was then constructed into the expression vector pET-32a and expressed in Escherichia coli BL21 （DE3） after induction with IPTG. SDS-PAGE and Western blot analysis showed the molecular weight of the recombinant GmolGOBP2 was about 32 ku,in consistence with the predicted result. [Conclusion] GmolGOBP2 was cloned and ex- pressed in prokaryotic expression system,which was helpful for further studies on its molecular structure and function in the olfactory system.