Two new labdane diterpenoids named heteronone A （1） and heteronone B （2） were isolated from the aerial parts of Leonurus heterophyllus Sweet. Their structures were established by various spectroscopic means, and t...Two new labdane diterpenoids named heteronone A （1） and heteronone B （2） were isolated from the aerial parts of Leonurus heterophyllus Sweet. Their structures were established by various spectroscopic means, and the structure of heteronone A is confn-med by X-ray diffraction analysis.展开更多
文摘通过cDNA末端快速扩增技术（rapid amplification of cDNA ends,RACE）从益母草（Leonurus heterophyllus Sweet）叶片中克隆获得了一个编码糖基转移酶的基因（LhsUGT）。该基因cDNA全长为1562 bp,开放阅读框（open reading frame,ORF）为1368 bp,编码455个氨基酸残基,其分子量和等电点分别为50.47 k D和5.52。生物信息学分析结果显示：LhsUGT编码的酶蛋白含有3种二级结构,其中α螺旋占43.1%,β折叠片占17.5%,无规卷曲占39.4%,其C端还发现了一段高度保守的PSPG结构域,说明LhsUGT编码的酶蛋白属于植物糖基转移酶超家族;对LhsUGT的氨基酸序列进行BLAST同源比对,发现益母草与其它植物的糖基转移酶序列相似性为26.4%-68.0%;系统进化树分析表明,LhsUGT蛋白属于拟南芥糖基转移酶超家族的L组,故推测它可能具有催化简单酚类发生糖基化的功能;SDS-PAGE电泳显示,原核表达系统成功表达出分子量约为69 k D的LhsUGT重组蛋白,其N端含有一段17.9 k D的His标签,且在IPTG诱导5 h后达到最高表达量。本研究结果为进一步开展体外酶促反应、阐明益母草糖基转移酶的生物学功能奠定了基础。
文摘Two new labdane diterpenoids named heteronone A （1） and heteronone B （2） were isolated from the aerial parts of Leonurus heterophyllus Sweet. Their structures were established by various spectroscopic means, and the structure of heteronone A is confn-med by X-ray diffraction analysis.
