以杜仲叶片cDNA为模板,采用反转录RCR及RACE技术分离出HDR基因的cDNA克隆,命名为EuHDR.EuHDR基因cDNA全长1 653 bp,5'端非编码区长82 bp,3'端非编码区长188 bp,编码460个氨基酸,与喜树HDR基因序列相似性最高,达82％；推导EuHDR氨基酸序列中包含转运肽序列(A1-A33)及植物HDR蛋白多个保守的功能位点(A117,A208,A262,A345)；EuHDR蛋白二级结构α-螺旋占35.65％,β-折叠占19.78％,螺环结构占44.57％；EuHDR蛋白三级结构为单体形式,呈不规则的三叶草形状；系统进化分析表明EuHDR蛋白与葡萄HDR蛋白的亲缘关系最为接近.%1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase (HDR) synthesizes IPP and DMAPP in the last step of the plant 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway.Homologous HDR gene cDNA was isolated from the leaves of Eucommia ulmoides by the method of reverse transcription polymerase chain reaction (RTPCR) and rapid amplification of cDNA ends (RACE) technique,and named as EuHDR.With the highest gene sequence similarity to Camptotheca acuminata (82％),the full-length cDNA of EuHDR was 1 653 bp including 5'non-coding region of 82 bp and 3' non-coding region of 188 bp and encoded 460 amino acids.The transit peptide sequence (A1-A33) and multiple conserved functional sites(A117,A208,A262,A345)of plant HDR protein were found in the deduced coding sequence of EuHDR.The secondary structure of EuHDR protein was predicted with proportion of α-helix to 35.65％,β-sheet to 19.78％ and loop/coil to 44.57％.The calculated protein tertiary structure of EuHDR was formed as monomer,which in space displayed asymmetrical shamrock-like shape.Phylogenetic analysis revealed that the evolutionary relationship of EuHDR protein was the closest to Vitis vinifera HDR protein.
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