高等植物F3′HcDNA及其氨基酸序列的生物信息学分析

用生物信息学方法对GenBank中拟南芥、油菜、大豆、矮牵牛和高梁等的类黄酮3′-羟化酶基因的cD-NA序列及其编码氨基酸序列的结构、理化性质、信号肽、疏水性/亲水性、亚细胞定位、跨膜结构域、功能域和进化关系进行了初步预测和分析。结果表明:不同植物类黄酮3′-羟化酶基因cDNA序列的相似性为69.5%,其起始密码子均为ATG,终止密码子均为TAA、TAG或TGA,包括5,′3′非翻译区和一个开放阅读框;不同植物类黄酮3′-羟化酶基因cDNA序列编码的氨基酸序列的理化性质基本一致,相似性为72.5%,含有6段保守氨基酸序列,是"PPGR"、"AGTDT"、"RPPN"、"AYNY"、"IKALLL"、"TPLS";在进化关系上可划分为两大类;不同植物类黄酮3′-羟化酶具有一个跨膜结构域、定位于内质网上,并有一段与细胞色素P450功能区相匹配的功能域;类黄酮3′-羟化酶属具转运肽的亲水性稳定分泌蛋白,其二级结构为α-β型,α-螺旋和无规卷曲为最主要的结构元件,延伸链和β-转角散布于整个结构。可为类黄酮3′-羟化酶基因的克隆和遗传操作提供理论参考。

Bioinformatical Analyses of the cDNAs and Their Amino Acid Sequences of F3′Hs in High Plants

The cDNAs of the flavonoid 3′-hydroxylase genes (F3′Hs) from Arabidopsis thaliana, Brassica napus, Glycine max, Petunia hybrida, Sorghum bicolor and so on in GenBank and the structures, physico chemical properties, signal peptides, hydrophobicity/hydrophilicity, subcellular localization, trans membrane topological structures, functional domains and evolutional relationship of the deduced amino acid sequences of the cDNAs were analyzed and predicted by using bioinformatical tools. The results showed that: the cDNAs of F3′Hs from different higher plants share 69.5% similarity, their initiation codons are ATG, termination codons are ether TAA, TAG or TGA, and they all contain an opening reading frame (ORF) which is flanked by a 5′ and 3′-untranslated region (5′ and 3′ UTR). The physico chemical properties of the deduced amino acid sequences are uniform on the whole; they share 725% similarity and can be classified into two kinds at the phylogenetic level group. Holding with a membrane spaning domain, F3′Hs are located on endoplasmic reticulum and contain 6 conserved amino acid sequences, i.e “PPGR”, “AGTDT”, “RPPN”, “AYNY”, “IKALLL” and “TPLS”, and a functional domain which matches the P450 binding domain. F3′Hs are hydrophilic, stable and secretory proteins with transit peptides. Their secondary structures belong to α-β type in which α-helixes and random coils are the major elements, and extended strands and β-turns spread in the whole structure. This paper could provide a theoretical reference for the cloning and genetic manipulation of unknown F3′H.