杧果中DXS基因的鉴定及与其他植物的比较分析

Identification of Mangifera indica DXS Gene and Comparison Analysis with Other Plants

1-脱氧-D-核酮糖5-磷酸合成酶(1-deoxy-D-xylulose-5-phosphate synthase, DXS)是2-C-甲基-D-赤藓糖醇-4-磷酸(2-C-Methyl-D-erythritol-4-phosphate, MEP)途径的第一个关键酶。本研究鉴定了杧果DXS基因,以拟南芥DXS基因为参考,通过BLASTP方法获得了番木瓜、金钱橘、甜橙、苹果、桃子、白梨、葡萄、中华猕猴桃、无油樟、小果野蕉的DXS基因的蛋白序列,共32条序列,对其进行了保守结构域、保守基序、系统发育、理化性质、蛋白二级结构分析等研究。保守结构域及保守基序分析结果表明,杧果DXS蛋白包含一个PLN02582结构域,保守结构域内包含6个motif,其宽度、排列顺序与大多数植物相同,说明DXS基因家族具有高度保守性。系统发育分析结果显示,单子叶植物纲与双子叶植物纲的DXS基因没有分别形成分支,推测在进化过程中DXS基因的分化在双子叶植物纲和单子叶植物纲形成之后。理化性质分析及蛋白二级结构分析结果显示,稳定性蛋白占65.63%,碱性蛋白占25%,所有蛋白均为亲水性蛋白。杧果DXS蛋白为酸性、不稳定蛋白,具有亲水性。杧果DXS蛋白的二级结构主要结构元件是无规则卷曲、α-螺旋。本研究为进一步阐明杧果DXS基因在萜类合成途径中的功能提供了理论依据。

1-deoxy-D-xylulose-5-phosphate synthase(DXS) is the first key enzyme involved in the 2-C-methylD-erythritol-4-phosphate(MEP) pathway. In this study, mango DXS gene was identified, with the reference of DXS gene of Arabidopsis thaliana, papaya, orange, apple, peach, white pear, grape, Actinidia chinensis, camphor camphora were obtained by BLASTP method which is total 32 sequences. Then, we analyzed conserved domains,motif, phylogenetic, physical and chemical characteristics, and second structure. The analysis showed that the DXS protein of mango contains a PLN02582 domain, and the conserved domain contains 6 motif, with the same width as most plants, indicating that the DXS gene family is highly conserved. Phylogenetic analysis showed that monocots and dicots did not form branch individually. It is inferred that the differentiation of DXS gene in the evolution process occurred after the formation of dicotyledon and Monocotyledon. Physical and chemical characteristics analysis showed that stable protein was 65.63%, basic protein was 25%, and all DXS proteins were hydrophilic proteins. Mango DXS protein was acidic, unstable and hydrophilic protein. The secondary structure of mangoDXS protein was mainly α-helix and random coil. This study provided foundation for further elucidating the function of mango DXS gene in terpenoid synthesis pathway.