油棕等热带植物DXS基因的生物信息学分析

Bioinformatics analysis of DXS gene from six tropical plants including oil palm(Elaeis guineensis Jacq.)

关键词:  油棕, DXS基因, 生物信息学, 系统进化树

Key words:  oil palm(Elaeis guineensis Jacq.), DXS gene, bioinformatics, phylogenetic tree

摘要:

油棕等热带植物含有丰富的胡萝卜素和维生素E等类异戊二烯物质,类胡萝卜素和甾醇等类异戊二烯物质在植物生命活动中扮演重要角色,并且对保护人类健康具有重要意义,MEP途径是合成类异戊二烯的重要途径之一。DXS是MEP途径中的第一个限速酶,其功能在油棕等热带植物中极其保守。为了弄清油棕等热带植物DXS的结构和功能特点,该研究利用生物信息学工具和软件对以油棕等热带植物类异戊二烯合成关键基因DXS为对象,进行核酸和氨基酸序列的理化性质、蛋白质结构以及功能结构域等分析,探讨了不同物种间的亲缘关系。结果表明:DXS基因起始密码子均为ATG,终止密码子则分为TAG、TAA和TGA,DXS蛋白质属于不具有信号肽的亲水性蛋白,可能作为转运蛋白在叶绿体基质中发挥作用,未发现明显的跨膜结构域,磷酸化位点有36个,其中丝氨酸、苏氨酸和酪氨酸位点分别为17、11和8个,无规则卷曲和α-螺旋是蛋白质二级结构主要的结构元件,三级结构预测具有DXS酶特征,硫胺素焦磷酸盐结合位点和PLN02582保守结构域,不同植物DXS功能结构域非常保守,可以作为判断不同物种间亲缘关系的重要依据。该研究结果为油棕等热带植物DXS的结构、功能分析和利用提供了进一步的信息,为其品质性状分子机制研究及遗传改良奠定了基础。

Abstract:

The paper unraveled structure characteristics, function features and phylogenetic relationships among species through analyzing nucleic acid and protein sequences of key gene DXS controlling isoprenoids synthesis of tropical plants as oil palm(Elaeis guineensis Jacq.)by using bioinformatics tools. Isoprenoids like carotenoids and sterols play an important role in life of plant, and have important significance for the protection of human health. Tropical plants as oil palm contains abundant isoprenoids like carotenes and vitamin E, MEP is one of the important pathway for isoprenoids biosynthesis. DXS as the first rate limiting enzyme in MEP pathway, its functions were highly conserved in diverse tropical plants. In order to understand the structure and function characteristics of DXS from tropical plants as oil palm, DXS genes nucleic acid and protein sequences from different plants including oil palm were analyzed such as physicochemical property, protein structure, and conserved domain by the tools of bioinformatics in this study. The results showed that the start codon of DXS gene was ATG, but termination codon was divided into TAG, TAA and TGA; DXS protein belonged to a hydrophilic protein without a signal peptide; It might played a role in the chloroplast stroma as a transport protein; No transmembrane domain was found, there were 36 phosphorylation sites, including 17 serine, 11 threonine and 8 tyrosine sites respectively; Random coil and alpha helix were the major structural elements of secondary structure; It had DXS enzyme character, thiamin diphosphate(TPP)binding sites and PLN02582 conserved multi-domains with tertiary structure analysis; Domains of DXS protein from different plant, were very conservative, and could be used as an important basis for determining genetic relationships among species. The results would provide further information for structure and functional analysis of DXS, and lay the foundation for molecular mechanism research and genetic improvement of quality traits for tropical plants including oil palm.