Department of Agronomy and Plant Breeding Sciences, College of Aboureihan, University of Tehran, Tehran, Iran.
Mol Biol Rep. 2012 Sep;39(9):8925-35. doi: 10.1007/s11033-012-1761-2. Epub 2012 Jun 22.
Isoprenoids or terpenoids are synthesized by two important units' including dimethylallyl diphosphate and isopentenyl diphosphate (IPP). Plants use two different methods for formation of IPP, which is a cytosolic and a plastidial method. The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR, EC 1.1.1.34) catalyzes the conversion of HMG-CoA to mevalonate, which is the first stage in the cytosolic pathway for biosynthesis of isoprenoid in plants. In this study, a total of fifty HMGR protein sequences from Gramineae and three animal samples including human, mouse and fruit fly were aligned and analyzed by computational tools to predict the protein properties, such as molecular mass, pI, signal peptide, transmembrane and conserved domains, secondary and spatial structures. Sequence comparison analysis revealed that there is high identity between plants and animals. Three catalytic regions including L domain, N domain and S domain were detected by structural modeling of HMGR. The tertiary structure model of Oryza sativa HMGR (Accession Number: NP_001063541) was further checked by PROCHECK algorithm, and showed that 90.3 % of the amino acid residues were located in the most favored regions in Ramachandran plot, indicating that the simulated three-dimensional structure was reliable. Phylogenetic analysis indicated that there is a relationship among species of Gramineae and other organisms. According to these results, HMGRs should be derived from a common ancestor.
异戊二烯或萜烯类化合物由两个重要单元合成，包括二甲基烯丙基二磷酸和异戊烯二磷酸（IPP）。植物有两种不同的方法形成 IPP，一种是胞质溶胶法，另一种是质体法。3-羟-3-甲基戊二酰辅酶 A 还原酶（HMGR，EC 1.1.1.34）催化 HMG-CoA 转化为甲羟戊酸，这是植物异戊烯类生物合成胞质溶胶途径的第一阶段。在这项研究中，对禾本科植物的 50 种 HMGR 蛋白序列和三种动物样本（包括人类、小鼠和果蝇）进行了比对和分析，利用计算工具预测蛋白质的特性，如分子量、等电点、信号肽、跨膜结构和保守结构域、二级和空间结构。序列比较分析表明，植物和动物之间存在高度的同源性。通过 HMGR 的结构建模，检测到三个催化区域，包括 L 域、N 域和 S 域。通过 PROCHECK 算法进一步检查了水稻 HMGR（登录号：NP_001063541）的三级结构模型，结果表明 90.3%的氨基酸残基位于 Ramachandran 图的最有利区域，表明模拟的三维结构是可靠的。系统发育分析表明，禾本科植物与其他生物之间存在一定的亲缘关系。根据这些结果，HMGR 应该来源于一个共同的祖先。
