人参皂苷合成生物学关键元件HMGR基因克隆与表达分析  

Cloning and expression analysis of a key device of HMGR gene involved in ginsenoside biosynthesis of Panax ginseng via synthetic biology approach

作　　者：罗红梅[1] 宋经元[1] 李雪莹[2] 孙超[1] 李春芳[1] 骆翔 李滢 陈士林[1,3] 

机构地区：[1]中国医学科学院,北京协和医学院药用植物研究所,濒危药材繁育国家工程实验室,北京100193 [2]山东中医药高等专科学校,山东烟台264199 [3]中国中医科学院中药研究所,北京100700

出　　处：《药学学报》2013年第2期219-227,共9页Acta Pharmaceutica Sinica

基　　金：吉林省重大科技攻关项目及国家科技支撑计划课题(2011BAI03B01);教育部"长江学者和创新团队发展计划"项目(IRT1150)

摘　　要：3-羟基-3-甲基戊二酸单酰辅酶A还原酶(3-hydroxy-3-methylglutaryl coenzyme-A reductase,HMGR)是甲羟戊酸途径中的第一个限速酶,直接催化人参皂苷的生物合成,是人参皂苷合成生物学研究中的重要元件之一。本研究克隆了人参(Panax ginseng)中一个新HMGR(命名为PgHMGR2)的编码区序列,并对其编码的蛋白进行生物信息学预测及基因表达分析。PgHMGR2与GenBank中的另一条人参HMGR的序列同源性仅为71.6%,因此,PgHMGR2是人参中HMGR基因家族的一个新成员。PgHMGR2基因全长1 770 bp,编码589个氨基酸残基。生物信息学预测PgHMGR2编码蛋白不含信号肽,包含两个跨膜区,具有HMGR催化作用的活性中心结构域。PgHMGR2编码蛋白与西洋参(Panax quinquefolius)的HMGR(GenBank登录号为ACV65036)具有99%的序列相似性。实时荧光定量PCR检测到PgHMGR2在人参花中表达量最高,其次为叶和根,茎中表达量最低。本研究是国内外首次获得的人参PgHMGR2基因的全长序列,为进一步鉴定PgHMGR2的功能及开展人参皂苷的合成生物学研究奠定基础。3-Hydroxy-3-methylglutaryl coenzyme-A reductase （HMGR）, the first enzyme of mavalonic acid pathway, is one of the key devices involved in ginsenoside biosynthesis based on synthetic biology approach. The open reading frame of a novel HMGR gene from Panax ginseng （PgHMGR2） was cloned and analyzed in this study. PgHMGR2-encoding protein showed 71.6% sequence similarity to a P. ginseng HMGR in GenBank. The full-length cDNA sequence of PgHMGR2 containing 1 770 bp, which encodes 589 amino acids, was cloned by RT-PCR strategy from P. ginseng. The bioinformatic analysis showed that PgHMGR2-encoding protein contained two transmembrane regions and the HMG_CoA_reductase domain, without signal peptide. The protein sequence of PgHMGR2 had the highest sequence similarity （99%） with Panax quinquefolius HMGR （GenBank accession No. ACV65036）. The expression level of PgHMGR2 was the highest in flower based on a real-time PCR analysis, followed by leaf and root, and the lowest was in stem. The result will provide a foundation for exploring the molecular function of PgHMGR2 involved in ginsenoside biosynthesis based on synthetic biology approach in P. ginseng plants.

关 键 词：3-羟基-3-甲基戊二酸单酰辅酶A还原酶 人参 人参皂苷 合成生物学 

分 类 号：R931[医药卫生—生药学]