条斑紫菜Mu型谷胱甘肽S-转移酶基因克隆与分析

Cloning and Analysis of a Mu Class GST in Laver Porphyra yezoensis

谷胱甘肽S-转移酶是动植物重要的解毒酶,分布广泛,类型众多。本研究利用生物信息学方法和RT-PCR技术获得了条斑紫菜一条新谷胱甘肽S-转移酶(PyGST2)基因的cDNA序列,该基因含有完整的开放阅读框,并且受到铅胁迫的诱导表达。PyGST2蛋白具有谷胱甘肽S-转移酶家族的保守结构域和保守氨基酸残基,与Mu型谷胱甘肽S-转移酶的序列一致性最高,与Alpha、Sigma和Pi型谷胱甘肽S-转移酶的次之,在进化树上远离高等植物的各型谷胱甘肽S-转移酶,而与动物的Mu型谷胱甘肽S-转移酶聚为一支。该Mu型谷胱甘肽S-转移酶的克隆为后续研究条斑紫菜抗逆机制奠定了基础。

Glutathione S-transferases（GSTs）are cellular multifunctional detoxification enzymes,and ubiquitously found in all types of organisms with a highly diverse family of proteins.In the present study,a novel member（PyGST2）of GST family in laver Porphyra yezoensis Ueda was cloned and analyzed using RT-PCR and bioinformatical tool.It was found that PyGST2 gene contained a continuous complete open reading frame encoding apolypeptide of 217 amino acids.The Pb2＋stress induced the expression of PyGST2 gene which contained conserved domains and amino acid residues of GST family.PyGST2 shared the highest identities with Mu class GSTs,and higher identities with Alpha,Sigma and Pi class GSTs among all kinds of GSTs.Phylogenetic analysis showed that PyGST2 was distinct from GST class of plant,but was most closely related to the Mu class GSTs.The findings of PyGST2 laid the foundation for further understanding of the molecular mechanisms of stress tolerance in the laver.