千里光α输入蛋白(α-Importin)的序列特征、结构与功能分析

Functional analysis of α-Importin in Senecio scandens, based on sequence and putative structural domain

关键词:  千里光  α-Importin  序列分析  结构预测

Key words:  Senecio scandens  α-Importin  sequence analyzing  structure prediction

摘要:

α输入蛋白存在于胞质溶胶中,是核孔转运复合体的重要组成部分,与核定位信号结合,通过受体介导蛋白物质转入和转出,在此过程中起连接器的作用。该研究以千里光全长cDNA文库为基础,对α输入蛋白的序列、结构、性质和功能进行了分析,并在千里光α输入蛋白核苷酸序列的基础上,采用生物信息学软件,分析α输入蛋白的氨基酸序列结构和基因进化树,得到了α输入蛋白的一级、二级、三级等结构和结构域特征,以此为依据,系统分析千里光α输入蛋白的理化性质、结构和功能。结果表明:千里光α输入蛋白基因编码529个氨基酸,与烟草(GenBank登录号:ABM05487.1)的同源性最高,为84%; 蛋白质分子量58.46 kDa,理论等电点5.08; 二级结构由α螺旋、无规则卷曲和延伸主链构成; 高级结构域由IBB和ARM结构构成; 三级结构是4个功能结构域构成的空间立体结构。此外,还发现千里光α输入蛋白具有调控激素反应、传输信号、细胞生长、信息转录和转录调控功能的概率较高,推测可能与细胞非凋亡性死亡、抗病性防御反应、激素受体反应以及基因转录调控表达密切相关。该研究结果可为其他物种α输入蛋白结构与功能关系的分析提供参考。

Abstract:

Alpha Importin is located in cytosolic space and is an important part of nuclear pore complex(NPC). After integrating with nuclear localization signal(NLS), it plays an essential role in mediating proteins' nucleocytoplasmic transporting as a connector. In the current study, to systematically explore the properties of physicochemical, sequence structure, function and the relationships between structural domain and its function of α-Importin, its nucleotide sequence was selected from a former constructed full-length cDNA library in Senecio scandens for probing its sequence features and composition, and gene's function by applying a series of bioinformatics software. The structure properties of primary, secondary, domain and tertiary of the amino acid sequence were analyzed, too. And the phylogenetic relationships among α-Importin of S. scandens with other species were also constructed. These exploration found that this gene encoded a length of 529 amino acid polypeptide with the calculated molecular weight of 58.46 kDa, and its theoretical isoelectric point was 5.08. It shared 84.0% identity with tobacco α-Importin gene(GenBank ID: ABM05487.1)by amino acid sequence alignment. The structure analysis showed its secondary structure was composed of α helix protein, a random coil and an extended main-chain. The function domain probing found the target gene was composed domains of IBB and ARM. While its three-dimensional structure was mainly consisted of four structural domains. In conclusion, this study found that the function of this α-Importin gene was regulation of hormone secretion, a signal transducer, growth factor, transcription and transcription regulation with higher rank of probability ratio. The current study also founded that this α-Importin gene could play important roles in many biology processes such as non-apoptotic programmed cell death, defence response of higher plants against pathogens, hormone receptor effect and gene transcription reactions and expression. According to the exploring of the properties of gene sequences, structure and function of α-Importin in S. scandens, this paper would provide a reference for similar analysis of the relationship between the structure and function of α-Importin genes in other species.