不同植物种类络合素合酶基因的特征分析

Analysis of Phytochelatin Synthase Genes' Characteristics in Different Plants

植物络合素合酶(Phytochelatin synthases,PCS)是催化谷胱甘肽(GSH)聚合生成植物络合素(PCs)的关键酶,在缓解重金属胁迫方面具有重要作用。该研究采用ProtParam、TMHMM、SignalP、Phyre2、Pfam、Clustal X和MEGA等生物信息学在线程序及软件,对苹果、湖北海棠和已在GenBank上登录的杜梨、拟南芥、水稻、烟草和百脉根等植物的络合素合酶(PCS)基因的核酸及氨基酸序列、理化性质、蛋白结构、系统发生树和功能域等进行了分析。结果表明:PCS蛋白氨基酸长度在465～506aa,理论等电点在5.67～7.77。PCS蛋白主要定位于细胞核中,除金鱼藻外,其它植物PCS蛋白均为不稳定蛋白。二级结构由α螺旋、无规则卷曲和延伸链等元件构成,空间结构高度相似。均具有一个植物络合素合酶(Phytochelatin)功能域,并具有3个预测的活性位点,属于植物络合素合酶蛋白家族。该研究为今后深入研究苹果中该基因的结构特征和功能提供了依据。

Phytochelatin synthase （PCS） is the key enzyme which catalyzes glutathione （GSH） polymerization to generate phytochelatins （PCs） in plants,and plays an important role in the mitigation of heavy metal stress. The nucleic acid and amino acid sequences,physical and chemical properties, protein structure, phylogenetic trees and functional domains of PCS genes from Malus domestica , Malus hupehensis , as well as Pyrus betuli folia , Arabidopsis thaliana , Oryza sativa , Nicotiana tabacum ,and Lotus japonicas which had been registered in GenBank were analyzed and investigated using bioinformatics online, melhods and software,such as ProtParam,TMHMM,SignalP,Phyre2 ,Pfam,Clustal X and MEGA. The resuhs showed thai the length of I＇CS proteins was between 465-506 amino acids,and the isoelectric poinl was between 5. 67-7. 77. The PCS proleins were nminly localized in the nucleus. The plant PCS proteins were unstable protein except Ceratophyllum demersum. The secondary structure of PCS proteins were nminly composed of α-helix, extended strand and random coil, and their spatial structure had a high degree Of similarity. All the PCS proteins belonged to phytochelatin synthases protein families,which containing a phytochelatin functional domain,and three predicted actiw＂ sites. This study would provide the basis for furlher investigating the structural characteristics and functions of this enzyme.