摘要
肉桂酸-4-羟化酶(Cinnamic acid-4-hydroxylase,C4H,EC 1.14.13.11)是苯丙烷途径中第二步反应酶,同时也是花色素苷前体生物合成途径中关键酶。该研究根据植物C4H的同源序列设计引物,通过RTPCR结合RACE的方法,在紫色甘薯中获得了与其相应的C4H基因,命名为Ib C4H(Gen Bank登录号GQ373157)。结果表明:(1)序列分析表明Ib C4H长1 668 bp,编码505个氨基酸,该氨基酸序列与其c DNA序列与Ib C4H蛋白与马铃薯C4H蛋白序列最为接近,与苹果、黑莓、大阿米芹、油菜一致性很高,均在70%以上。(2)二级结构预测表明α-螺旋和无规则卷曲是Ib C4H蛋白最大量的结构元件,而延伸链则散布于整个蛋白中。(3)三维结构建模预测,Ib C4H蛋白具备细胞色素P450氧和铁离子结合位点等典型的C4H结构。该研究结果为进一步了解花色素苷生物合成途径中的作用奠定了基础,也为花青素生物合成分子机理和代谢调控提供了靶位点和理论参考。
（ Cinnamic acid-4-hydroxylase,C4 H,EC 1.14.13.11） is the second key enzyme involved in the biosynthetic pathway of phenylpropanoid and precursors of anthocyanin biosynthesis. Based on c DNA sequence conserved domain of C4 H,a pair of primers were designed and used to amplify a fragment of Ib C4 H gene（ Gen Bank accession： GQ373157）by RT-PCR from sweet potato using RT-PCR and RACE technique. A 1 668 bp full-length c DNA sequence was obtained. Analysis of C4 H c DNA indicated that it encoded a peptide containing 505 amino acids and the sequence comparison with the C4 H gene of potatoes,apples,blackberries,ammi majus and rapes showed that identity was all above70%. The predicted secondary structure demonstrated that alpha helix and random coil were the most important structural conformation. However,extended chain distributed in the whole protein. The predicted tertiary structure demonstrated that Ib C4 H had binding sites of cytochrome P450 with oxygen and iron. The study will be helpful to understand more about the roles involved in anthocyanin biosynthesis at the molecular level and provides a candidate genes for metabolic engineering of anthocyanin biosynthesis pathway in purple-fleshed sweetpotato.
作者
张华玲
刘绪
杨春贤
黄元射
傅玉凡
张启堂
ZHANG Hualing;LIU Xu;YANG Chunxian;HUANG Yuanshe;FU Yufan;ZHANG Qitang(College of Chemistry and Life Sciences, Chengdu Normal University, Chengdu 611130, China;School of LifeSciences, Southwest University, Chongqing Sweet Potato Research Center, Chongqing 400715, China;College of Agronomy, Anshun University, Anshun 561000, Guizhou, China)
出处
《广西植物》
CAS
CSCD
北大核心
2018年第4期501-508,共8页
Guihaia
基金
贵州省科学技术厅三方联合科技基金[黔科合LH字(2015)7687]
关键词
甘薯
肉桂酸-4-羟化酶
基因克隆
序列分析
sweet potato
cinnamic acid-4-hydroxylase
gene cloning
sequence analysis
