【摘要】 以萝芙木叶片为材料,应用RT-PCR方法首次克隆了萝芙木萜类吲哚生物碱(terpeno id indo le a lka lo ids,T IA s)生物合成途径中重要的限速酶——异胡豆苷合成酶(strictos id ine syn thase,STR)基因(G enB ank登录号DQ 0170054)并进行了生物信息学分析,以pCAM B IA 1304为基本载体构建其植物高效表达载体pCAM B IA 1304+-R vSTR.生物信息学分析表明,该基因的编码区长度为1 035 bp,编码344个氨基酸的多肽,其理论分子量为38.2kD,等电点为5.2,N-端有一长度为27个氨基酸的信号肽;二级结构预测表明,延伸链和不规则盘绕是R vSTR蛋白最大量的结构元件,而α-螺旋和β-转角则散布于整个蛋白质中.同源性分析表明,R vSTR和其它植物来源的STR同源;采用M EGA 3构建了具代表性的植物STR的分子系统发育树,首次提出植物来源的STR分为2种类型,即STR 1和STR 2,其中来源于能够产生T IA s的植物的STR属于STR 2类型.更多还原

【Abstract】 RT-PCR was adopted to clone strictosidine synthase gene(accession No.:DQ0170054),which was an important enzyme in biosynthetic pathway of terpenoid indole alkaloids(TIAs) in Rauvolfia verticillata,with R.verticillata leaves for the first time and analyze its bio-information.Its high-efficiency expression vector pCAMBIA1304~+-RvSTR was constructed with pCAMBIA1304.Its biosynthetic information analysis indicated that the encoding region of the gene was 1 035 bp,encoded polypeptides of 344 amino acids,which had a theoretical molecular weight of 38.2 kD,an isoelectric point of 5.2,and a signal peptide of 27 amino acids at its N-end.Predicted secondary structure revealed that extended strand random coil were the structural conformations in the greatest quantities in RvSTR protein and α-spiral and β-outer corner distributed in the whole protein.The homology analysis showed that RvSTR and STRs from other plant sources are homologous;MEGA3 was adopted to construct the phylogenetic tress of typical plant STRs and it was put forward for the first time that STR of plant origins had two typyes,STR1 and STR2 and the STR from the plants capable of producing TIAs belonged to STR2.更多还原