从狼毒大戟中克隆蓖麻烯合成酶基因

本研究采用RACE-PCR技术从狼毒大戟(Euphorbia fischeriana Steud.)根中克隆到一个蓖麻烯合成酶(casbene synthase)基因,命名为EfCS(GenBank登录号为:JN862821)。该基因长1969bp,编码602个氨基酸,具有典型的萜类合成酶的基因结构。对CS基因编码氨基酸序列进行生化特性分析发现其理论等电点为5.36,分子量为69.3648kD。通过疏水性分析,发现CS整体表现为亲水性。进行导肽分析结果发现其具有叶绿体导肽。二级结构预测表明,CS蛋白由α-螺旋、延伸链、β-转角和随意卷曲构成,它们分别占到64.95%、6.64%、3.16%和25.25%。另外,对CS蛋白质进行三级结构预测,发现蓖麻烯合成酶属Ⅰ类萜类合成酶。

Casbene Synthase Gene cloned from Euphorbia fischeriana Steud.

Casbene synthase may play an important role in biosynthesis of tigliane type terpenoid.Casbene synthase gene,named as EfCS(GenBank accession number JN862821),was cloned from the root of Euphorbia fischeriana Steud.through RACE-PCR.The fragment was 1 969 bp in length and contained an open reading frame coding a polypeptide of 602 amino acids.This CS protein from E.fischeriana has a typical terpenoid synthase gene structure.Through biochemical analysis of the amino acid sequence coding by CS gene,we found the theoretical isoelectric point of CS is 5.36 and the molecular weight is 69.364 8 kD.By hydrophobic analysis,we found the overall performance of CS is hydrophilic.The lead peptide analysis revealed that the peptide has a chloroplast guide sequence.Secondary structure prediction showed that this CS protein is mainly composed with α-helix,extended chain,β-turn and random coil,which accounts for 64.95%,6.64%,3.16% and 25.25% respectively.Protein tertiary structure prediction showed that our casbene synthase belongs to class Ⅰ terpene synthase.