滇龙胆GrGPPS基因的克隆及其序列分析与原核表达

Cloning, sequence analysis, and prokaryotic expression of GrGPPS gene in Gentiana rigescens

目的从滇龙胆Gentiana rigescens幼叶中克隆单萜化合物合成的关键酶牻牛儿基焦磷酸合成酶基因GrGPPS,进行序列特征分析和原核表达。方法根据三年生滇龙胆转录组GrGPPS基因序列,设计特异性引物,通过RT-PCR扩增得到GrGPPS cDNA序列,并进行TA克隆、测序及序列分析;构建原核表达载体pGEX-4T-1-GrGPPS,转入Escherichia coli Rosetta(DE3)中,在37℃、1.0 mmol/L IPTG诱导下进行表达。结果 GrGPPS cDNA全长1 107 bp,编码369个氨基酸;序列分析表明,GrGPPS基因是异戊烯基合成酶家族的成员;氨基酸序列系统发育分析表明,GrGPPS与金鱼草AmGPPS亲缘关系最近;构建pGEX-4T-1-GrGPPS重组质粒,获得稳定的pGEX-4T-1-GrGPPS原核表达体系。SDS-PAGE结果表明所表达蛋白与预期蛋白大小一致。结论克隆了GrGPPS基因,建立pGEX-4T-1-GrGPPS稳定的原核表达体系,为进一步纯化和鉴定GPPS蛋白并研究其结构和功能奠定基础。

Objective To obtain the indispensable key enzyme involved in the monoterpene biosynthesis, the geranyl diphosphate synthase gene GrGPPS was cloned from Gentiana rigescens, and its sequence analysis and prokaryotic expression were performed. Methods According to the GrGPPS gene sequence oftranscriptome of triennial G. rigescens, a pair of specific primers was designed, and the full length ofcDNA sequences was obtained by RT-PCR. Then TA cloning, sequencing and sequence analysing were performed. Prokaryotic expression vector pGEX-T-1-GrGPPS was constructed and transformed into Escherichia coli Rosetta for expression under 37 ℃ and induced by 1 mmol/L IPTG Results The GrGPPS cDNA had a length of 1 107 bp coding for 369 amino acids. Sequence analysis showed that GrGPPS was the member of ＂short-chain prenyltransferases＂ super family. Results of phylogenic analysis showed that GrGPPS was at the same evolutionary branch with AmGPPS. The SDS-PAGE results displayed that the expressed proteins were consistent with the anticipated size. Conclusion The GrGPPS gene is cloned from G. rigescens, and the stable prokaryotic expression system of pGEX-T-1-GrGPPS is constructed. This work will provide a foundation for further purification, structure, and functional research of GrGPPS protein.