北葶苈子GGPS基因的克隆、序列分析与原核表达

Cloning, Sequence Analysis and Prokaryotic Expression of GGPS Gene from Lepidium apetalum

目的:获得北葶苈子(Lepidium apetalum)中牻牛儿基牻牛儿基焦磷酸合成酶(geranylgeranyl pyrophosphate synthase,GGPS)的编码基因,进行生物信息学分析,在大肠杆菌中表达该蛋白。方法:根据北葶苈子转录组测序结果中的GGPS基因序列,设计特异性引物,通过PCR扩增得到北葶苈子GGPS的c DNA序列,进行TA克隆、测序及序列分析,构建原核表达载体并于大肠杆菌中表达北葶苈子GGPS蛋白。结果:得到北葶苈子GGPS c DNA全长1 146 bp,编码381个氨基酸;序列分析表明北葶苈子GGPS基因编码的氨基酸序列包含类异戊二烯合成酶结构域,氨基酸序列进化关系表明北葶苈子GGPS与拟南芥(Arabidopsis thaliana)和白芥(Sinapis alba)亲缘关系最近;成功构建了p ET-32a-La GGPS原核表达载体,并在大肠杆菌BL21菌株中成功诱导表达。结论:首次克隆得到北葶苈子GGPS基因,并在大肠杆菌中成功表达了北葶苈子GGPS蛋白,为纯化该蛋白并研究其结构和功能奠定了基础。

This study was aimed to clone the GGPS （geranylgeranyl pyrophosphate synthase） gene from Lepidium apetalum, to analyze its sequence, and to express the protein in E.coli expression system. Specific PCR cloning primers were designed for GGPS gene from Lepidium apetalum according to the full-length sequence from a previous transcriptome sequencing project. PCR amplification was performed with this primer pair on a leaf cDNA template. TA cloning, sequencing and sequence analysis were performed. GGPS gene from Lepidium apetalum was expressed in the E.coli expression system. The results showed that the full-length GGPS cDNA from Lepidium apetalum was 1 146 bp coding a protein of 381 amino acids. The LaGGPS protein had an isoprenoid synthase domain. According to a phylogenetic tree constructed with multiple alignment of GGPS protein sequences from various plant species, GGPS protein from Lepidium apetalum was the closest to Arabidopsis thaliana and Sinapis alba. The prokaryotic expression vector pET-32a-LaGGPS was also constructed successfully. The protein was expressed in E.coli BL21 strain. It was concluded that the cloning and prokaryotic expression of LaGGPS gene provided a foundation for a follow-up research of its function with protein purification and activity analysis.