植物萜类合成酶1-脱氧-D-木酮糖-5-磷酸还原异构酶的分子结构特征与功能预测分析

An Analysis of Molecular Structural Character and Function Prediction on 1-deoxy-D-xylulose-5-phosphate Reductoisomerase, a Key Enzyme in Plant Isoprenoid Biosynthesis

采用生物信息学的方法和工具对已在GenBank上注册的拟南芥、玉米、岩蔷薇、水稻、黄花蒿、亚麻等植物的萜类合成酶1-脱氧-D-木酮糖-5-磷酸还原异构酶的核酸及氨基酸序列进行分析,并对其组成成分、转运肽、跨膜拓朴结构域、疏水性/亲水性、蛋白质二级及三级结构、分子系统进化关系等进行预测和推断。结果表明:该类酶基因的全长包括5′、3′非翻译区和一个开放阅读框,无跨膜结构域,是一个具转运肽的亲水性蛋白,包括两个功能DXR结合motif及两个功能NADPH结合motif,α-螺旋和不规则卷曲是蛋白质二级结构最大量的结构元件,β-转角和β-折叠散布于整个蛋白质中,蛋白质的功能域在空间结构上折叠成“V”形,“V”形的两臂由N-端与C-端构成,“V”形的底部,是N-端臂与C-端臂的结合域。

In the present study, 1-deoxy-D-xylulose-5-phosphate reductoisomerase from Zea mays, Arabidopsis thaliana, Cistus incanus subsp, creticus, Oryza sativa, Artemisia annua and Linum usitatissimum, which were registered in GenBank, were analyzed and predicted by the tools of bioinformatics in the following aspects： the composition of nuclei acid sequences and amino acid sequences, transit peptides, transmembrane topological structure, hydrophobicity or hydrophilicity, secondary and tertiary structure of protein, molecular phylogenetic evolution and so on. The results as following： the full-length gene of DXR contains an opening reading frame, 5＇-untranstrated region and 3＇-untranstrated region; DXR is a hydrophilic and non-transmembrane protein with transit peptides; the amino acid sequences of DXR include two functional DXR binding motifs and two functional NADPH binding motifs; the main motif of predicted secondary structure of DXR are alpha helix and random coil, beta turn and extended strand are spreaded in the whole secondary structure of protein; the predicted tertiary structure of functional domain of DXR consists of three domains arranged to form an overall V-shaped molecule. The Nterminal domain forms one arm of the V and C-terminal domain forms the second arm of the V. The apical region of the V is formed by a connective N-terminal and C-terminal domain.