管状花目中多酚氧化酶的序列分析与功能预测

Sequence Analysis of Polyphenol Oxidase in Tubiflorae Plants and Function Prediction

以管状花目(Tubiflorae)中5个物种7个多酚氧化酶基因(PPO)序列为研究对象,采用序列对比分析和功能预测方法,研究了这些基因序列的碱基、酶蛋白氨基酸序列数量与比例,以及氨基酸序列中蛋白激酶C磷酸化、酪氨酸激酶Ⅱ磷酸化、N-糖基化、N-豆蔻酰化、酰胺化、cAMP及cGMP蛋白激酶磷酰化6个功能位点结构域特征,以期揭示PPO酶调控的功能位点。结果表明:管状花目中丹参毛状根PPO基因含有G+C碱基最多,氨基酸中丙氨酸和亮氨酸含量也最高(16.9%),并含有最多的酪氨酸激酶Ⅱ磷酸化位点(11个)。丹参毛状根PPO酶不具备信号肽结构,有1个卷曲螺旋,是无跨膜结构的亲水性蛋白。该试验为研究PPO酶调控酚酸类物质次生代谢的分子机制,特别是蛋白与蛋白、蛋白与基因之间的互作奠定了基础。

The sequences of seven polyphenol oxidase genes（PPO）in five species of Tubiflorae was analyzed by using the methods of sequence comparison and functional domain prediction.The number of bases and amino acids,and six functional sites including protein kinase C phosphorylation site,casein kinase II phosphorylation site,N-myristoylation,N-glycosylation,amidation site and cAMP-and cGMP-dependent protein kinase phosphorylation site,were analyzed to discover those regulation sites of PPO.The results showed that among Tubiflorae plants,PPOgene cloned from hair roots of Salvia miltiorrhiza Bunge（SmPPO）had the most G＋C bases.The highest content of alanine and leucine（16.9%）was found in its amino acid sequences（SmPPO）,as well as the most casein kinase II phosphorylation sites（11）.No signal peptide was found in SmPPO,but it existed a coiled coil.The SmPPO was a hydrophilic protein but no transmembrane domain.This work provided foundation to investigate the molecular mechanism how PPO regulated the accumulation of phenolics,sepecially for interaction between protein and protein,protein and gene.