中文摘要：

根据报道的十几种昆虫CYP4家族基因的氨基酸序列保守区域设计一对引物,利用RT-PCR技术扩增编码青杨脊虎天牛Xylotechus rusticus中肠细胞色素氧化酶CYP4G2蛋白的cDNA片段,构建原核表达载体pET-CYP4G2,将其转化入大肠杆菌Escherichia coli JM109中表达。序列分析结果表明,该基因（CYP4G2,GenBank登录号为EF429250）保守区域阅读框全长387bp,编码129个氨基酸残基,预测分子量和等电点分别为16.9kD和5.75;推导的氨基酸序列与已报道的昆虫CYP4家族氨基酸序列一致性较高（63%～86%）,且具有细胞色素氧化酶的典型特征。IPTG诱导后,SDS-PAGE电泳检测到一条22kD大小的外源蛋白,与预测融合蛋白的分子量大小相应。CO差光谱分析证明重组菌表达了有活性的pET-CYP4G2。

英文摘要：

A pair of primers was designed based on the reported sequences of conservative amino acid regions of CYP4 protein family in insects. The cDNA encoding the cytochrome CYP4G2 protein was isolated from the intestines of Xylotechus rust/cus L. by reverse transcription polymerase chain reaction （RT-PCR）. The cDNA fragment was constructed to prokaryotic expression vector that named pET-CYP4G2 for overexpression in Escherichia coli JM109. Sequence analysis showed that the full-length of CYP4 G2 （GenBank accession no. EF429250） open reading frame （ORF） was 387 bp, encoding 129 amino acid residues; the predicted MW and pI were 16.9 kD and 5.75, respectively. The deduced amino acid sequence showed high identity to the reported sequences of CYP4 family amino acids from other insects （63 % - 86 % ） and shared the typical structural features of cytochrome from other insects. After induction with IPTG, its molecular weight was found to be about 22 kD by checking with SDS polyacrylamide gel electrophoresis. The molecular weight was the same as the prediction of fusion protein. Carbon monoxide （CO） difference spectrum analysis confirmed that the recombinant strain expressed pET-CYP4G2 with biological activity.