油菜ACO1基因家族成员及其蛋白质高级结构比较

Comparison of ACO1 Gene Family Members and Their Protein Higher Structure in Brassica napus L.

摘要: 乙烯对植物的生长发育具有重要的调节作用，尤其在植物抵抗逆境胁迫过程中扮演着重要角色。ACO1 (1-aminocyclopropane-1-carboxylate oxidase 1)是乙烯合成过程中的一个限速酶，对乙烯的生物合成具有调控作用。菜籽油是我国居民的主要植物食用油之一，提高油菜抗逆性和产品品质是保证我国植物油持续供应的重要育种环节。本文利用生物信息学的方法，对油菜ACO1基因家族进行全基因组鉴定，并从基因的基本信息、蛋白质的亚细胞定位、保守结构域、蛋白质高级结构以及进化关系等方面对油菜ACO1基因家族进行了分析研究。结果显示，在油菜基因组中，ACO1基因家族包含7个基因位点，其中1个为不编码假基因，其余6个基因位点各编码1个蛋白质，这些基因在A基因组和C基因组上都存在，编码的蛋白质均定位于细胞质中。油菜ACO1蛋白质序列长度均为310AA，其氨基酸组成差异较小，均属于PLN02403超家族，行使氨基环丙烷羧酸氧化酶的功能。在油菜ACO1蛋白质的二级结构中，α-螺旋和β-折叠都较多，α-螺旋数量在11~13个之间，β-折叠的数量在13~14个之间，蛋白质序列中间段的二级结构差异极其微小，为保守区，而N端和C端的二级结构差异较中间段的大，或许在功能上有一定的差异。同源建模法所得到的空间结构中N端和中间部分的空间结构差异微小，较保守，而C末端序列的空间结构差异较明显，为可变区，可能是活性位点，与酶的催化活性有关。

Abstract: Ethylene plays an important role in regulating the growth and development of plants, especially in the process of plant resistance to adversity stress. ACO1 (1-aminocyclopropane-1-carboxylate oxidase 1) is a rate-limiting enzyme in the process of ethylene synthesis and has a regulatory effect on ethylene biosynthesis. Rapeseed oil is one of the main vegetable edible oils for Chinese residents, and improving the stress-resistance and product quality of rapeseed is an important breeding step to ensure the continuous supply of vegetable oil in our country. This article uses bioinformatics methods to identify the ACO1 gene family members in Brassica napus L., and analyzes them from the basic information of genes, protein subcellular location, conserved domains, protein structure, and evolutionary relationships. The results showed that the ACO1 gene family in Brassica napus L. contains 7 genetic locus, one of which is a non-coding pseudogene, and the remaining 6 gene loci each encode a protein. These genes exist on both the A genome and the C genome. The encoded proteins are all located in the cytoplasm. The length of ACO1 protein sequence is all 310 amino acid (AA), and the difference of their amino acid composition is small, all belong to the PLN02403 superfamily, and perform the function of aminocyclopropane carboxylic acid oxidase. In the secondary structure of rape ACO1 proteins, there are more α-helices and β-sheets. The number of α-helices is between 11 to 13, and the number of β-sheets is between 13 to 14. The secondary structure difference in the middle segment of the sequence is extremely small, which is a conserved region, while the secondary structure difference between the N-terminal and C-terminal is larger than that of the middle segment, and there may be a certain difference in function. The spatial structure difference between the N-terminal and the middle part of the spatial structure obtained by the homology modeling method is small and conservative, while the spatial structure of the C-terminal sequence is more obvious. It is a variable region, which may be the active site, related to the catalytic activity of the enzyme.