日本蛇根草无色花青素双加氧酶基因的克隆及其序列分析

Cloning and Sequence Analysis of LDOX Gene in Ophiorrhiza japonica

无色花青素双加氧酶（LDOX）是花青素合成途径末端的一个关键酶,在该酶的催化作用下,能将无色花色素转变为有色花色素。本研究采用RT-PCR方法成功克隆出日本蛇根草LDOX基因的cDNA序列后,并对其进行了生物信息学分析。分析结果显示,日本蛇根草LDOX基因的cDNA全长为1 041 bp,编码346个氨基酸,理论等电点为5.50,预测其蛋白分子量为38.63 k D,LDOX蛋白为不稳定蛋白,不存在信号肽,很可能定位在细胞质中。二级结构分析显示,其无规则卷曲的含量最高,与三级结构预测结果相符合。日本蛇根草LDOX基因的克隆与生物信息学分析对于进一步研究该类酶的结构和功能以及植物花青素的生物合成具有重要意义。

Leucoanthocyanidin dioxygenase（LDOX） is the key enzyme at end of anthocyanidin biosynthesis pathway, which converts colorless anthocyanidin into the colored one under the catalysis. In this study, the integrated c DNA sequence of LDOX in Ophiorrhiza japonica was cloned successfully by RT-PCR method, and then was conducted to bioinformatics analyses. The results showed that the full-length CDS of LDOX was 1 041 bp and encoded 346 amino acids, and its theoretical isoelectric point was 5.50 and the predicted molecular weight was 38.63 k D. LDOX of Ophiorrhiza japonica was unstable protein and had no signal peptide, which was likely to locate in the cytoplasm. Secondary structure analysis showed that the proportion of random curl was the highest,and this result was consistent with the prediction of its tertiary structure. Cloning and bioinformatics analysis of LDOX from Ophiorrhiza japonica had important significance for further studies on structure and function of LDOX as well as plant anthocyanin biosynthesis.