玉米ZmASA2基因的克隆与生物信息学分析

Cloning and Bioinformatics Analysis of ZmASA2 Gene in Maize

邻氨基苯甲酸合成酶(Anthranilate synthase,AS),是存在于植物细胞中催化色氨酸合成的复合酶,由α亚基和β亚基组成。本研究采用RT-PCR技术,从玉米B73中克隆得到一个编码邻氨基苯甲酸合成酶α亚基同源基因的cDNA片段,命名为ZmASA2。氨基酸序列分析表明,该cDNA片段全长1731 bp,预测编码一条含577个氨基酸的多肽,分子量为64.48 kD,理论等电点为6.64。生物信息学分析表明,ZmASA2属于定位在细胞质中的亲水性蛋白,二级结构主要为α螺旋。系统发育分析表明,ZmASA2蛋白与南荻和高粱的AS在进化上种属关系最近。qRT-PCR结果显示,ZmASA2在授粉后30 d籽粒表达量最高,其次是茎。

Anthranilate synthase(AS)is a complex enzyme that catalyzes the synthesis of tryptophan in plant cells,consisting ofαsubunits andβsubunits.In this study,a cDNA fragment encodingαsubunit homologouSgene of anthranilic acid synthase wascloned from corn B73 by RT-PCR technique,named ZmASA2.Amino acid sequence analysis showed that the total length of the cDNA fragment was1731 bp,and it waspredicted to code a polypeptide containing 577 amino acids,with a molecular weight of about 64.48 kD and a theoretical isoelectric point of 6.64.BioinformaticSanalysis showed that ZmASA2 wasa hydrophilic protein located in the cytoplasm,and itSsecondary structure wasmainlyαhelix.Phylogenetic analysis showed that ZmASA2 protein wasthe closest phylogenetic relation to ASof MiscanthuSlutarioripariuSand sorghum.The results of qRT-PCR showed that the expression of ZmASA2 wasthe highest at 30 days after pollination,followed by the stem.