Jiang Jihong, Kai Guoyin, Cao Xiaoying, Chen Fengmei, He Dongning, Liu Qun
Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, Xuzhou Normal University, Xuzhou, 221116, People's Republic of China.
Biosci Rep. 2006 Apr;26(2):171-81. doi: 10.1007/s10540-006-9010-3.
The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) catalyzes the conversion of HMG-CoA to mevalonate, which is the first committed step in the pathway for isoprenoid biosynthesis in plants. A full-length cDNA encoding HMGR (designated as EuHMGR, GenBank Accession No. AY796343) was isolated from Eucommia ulmoides by rapid amplification of cDNA ends (RACE). The full-length cDNA of EuHMGR comprises 2281 bp with a 1770-bp open reading frame (ORF) encoding a 590-amino-acid polypeptide with two trans-membrane domains revealed by bioinformatic analysis. Molecular modeling showed that EuHMGR is a new HMGR with a spatial structure similar to other plant HMGRs. The deduced protein has an isoelectric point (pI) of 6.89 and a calculated molecular weight of about 63 kDa. Sequence comparison analysis showed that EuHMGR had highest homology to HMGR from Hevea brasiliensis. As expected, phylogenetic tree analysis indicated that EuHMGR belongs to plant HMGR group. Tissue expression pattern analysis showed that EuHMGR is strongly expressed in the leaves and stems whereas it is only poorly expressed in the roots, which implies that EuHMGR may be a constitutively expressing gene. Functional complementation of EuHMGR in HMGR-deficient mutant yeast JRY2394 demonstrated that EuHMGR mediates the mevalonate biosynthesis in yeast.
3-羟基-3-甲基戊二酰辅酶A还原酶（HMGR）催化HMG-CoA转化为甲羟戊酸，这是植物类异戊二烯生物合成途径中的首个关键步骤。通过cDNA末端快速扩增（RACE）技术，从杜仲中分离出了一个编码HMGR的全长cDNA（命名为EuHMGR，GenBank登录号为AY796343）。EuHMGR的全长cDNA包含2281 bp，其中有一个1770 bp的开放阅读框（ORF），编码一个590个氨基酸的多肽，生物信息学分析显示该多肽具有两个跨膜结构域。分子建模表明，EuHMGR是一种新的HMGR，其空间结构与其他植物HMGR相似。推导的蛋白质的等电点（pI）为6.89，计算分子量约为63 kDa。序列比较分析表明，EuHMGR与巴西橡胶树的HMGR同源性最高。正如预期的那样，系统发育树分析表明EuHMGR属于植物HMGR组。组织表达模式分析表明，EuHMGR在叶和茎中强烈表达，而在根中表达较弱，这意味着EuHMGR可能是一个组成型表达基因。EuHMGR在HMGR缺陷型突变酵母JRY2394中的功能互补证明，EuHMGR介导酵母中甲羟戊酸的生物合成。
