藏药翼首草角鲨烯合成酶的生物信息学分析  

Bioinformatics Analysis of Squalene Synthase in Pterocephalus hookeri(C.B.Clarke) H?eck

作　　者：何焱 李忠玥 李卿 吕宗友 权红[1] 张磊 兰小中[1] He Yan;Li Zhongyue;Li Qin;LüZongyou;Quan Hong;Zhang Lei;Lan Xiaozhong(Animal Husbandry College and TAAHC-SWU Medicinal Plant R&D Centre,Tibet Agricultural,Nyingchi,860000;Department of Pharmaceutical Botany,School of Pharmacy,Second Military Medical University,Shanghai,200433;Department of Pharmacy,Shanghai Changzheng Hospital,Second Military Medical University,Shanghai,200003)

机构地区：[1]西藏农牧学院西南大学药用植物联合研发中心,林芝860000 [2]中国人民解放军海军军医大学药学院药用植物学教研室,上海200433 [3]中国人民解放军海军军医大学附属长征医院,上海200003

出　　处：《基因组学与应用生物学》2020年第7期3139-3150,共12页Genomics and Applied Biology

基　　金：第四次全国中药资源普查西藏自治区(中)藏药资源普查项目(20180611-542229);西藏农牧学院研究生创新计划项目(YJS2017-09)共同资助。

摘　　要：翼首草(Pterocephalus hookeri)是西藏地区传统藏药材,目前研究发现其主要药效物质以三萜皂苷及环烯醚萜苷为主。为研究藏药翼首草三萜类化合物下游途径关键酶SQS调控三萜类物质的合成机制,本研究首次利用翼首草转录组数据库筛选出翼首草角鲨烯合酶(PhSQS)基因,采用生物信息学方法对SQS氨基酸的组成、理化性质、疏水/亲水性、蛋白质结构及其功能域等进行了预测与分析。通过同源性比对,构建了SQS蛋白的系统发育树。研究结果显示PhSQS蛋白序列与烟草、人参、三七同源性较高,PhSQS开放阅读框(ORF)为1251 bp,相对分子量为47 kD,氨基酸残基个数为417,理论等电点为8.38。PhSQS蛋白存在明显的疏水区域和亲水区域。PhSQS蛋白二级结构的主要结构元件是α-螺旋和无规则卷曲,含有SQS蛋白功能结构域。本研究获得的PhSQS基因信息,能够确定PhSQS蛋白具有催化鲨烯的功能,为今后进一步研究藏药翼首草次生代谢调控提供理论依据。Pterocephalus hookeri is a traditional Tibetan medicinal material in Tibet.It is currently found that its main medicinal substances are triterpenoid saponins and iridoid glycosides.In order to study the regulation mechanism of the Squalene synthase(SQS,EC:2.5.1.21),which is a key enzyme of the downstream pathway of the triterpenoids of the traditional Tibetan medicine Pterocephalus hookeri.In this study,the Pterocephalus hookeri squalene synthase(PhSQS)gene was screened from Pterocephalus hookeri transcriptome database for the first time.The composition,physicochemical properties,hydrophobicity/hydrophilicity,protein structure and functional domains of SQS were predicted and analyzed by bioinformatics.The phylogenetic tree of SQS protein was constructed by homology comparison.The amino acid sequence homology alignment showed that the amino acid sequence of Ph SQS was highly homologous with ginseng,notoginseng,tobacco and so on.In this study,the open reading frame of Ph SQS was 1251 bp,the number of amino acid residues was 417,the relative molecular weight was 47 k D,and the theoretical isoelectric point was 8.38.It was found that there are obvious hydrophobic and hydrophilic regions in the PhSQS protein.The main structure of the PhSQS protein of the sylvestris The structural elements are alpha-helices and random coils containing the SQS protein functional domain.Bioinformatics analysis of PhSQS protein can be confirmed that it has the function of catalyzing squalene and provide a theoretical basis for further study on the regulation of secondary metabolism of Euphorbia chinensis in the future.

关 键 词：藏药 翼首草 生物信息学 角鲨烯合成酶 

分 类 号：S567.239[农业科学—中草药栽培] Q943.2[农业科学—作物学]