Open AccessCharacterization analysis and heavy metal‐binding properties of Cs MTL 3 in Escherichia coli
Author(s) -
Xu Xing,
Duan Ling,
Yu Jingwen,
Su Chenggang,
Li Jinhua,
Chen Dan,
Zhang Xingguo,
Song Hongyuan,
Pan Yu
Publication year - 2018
Publication title -
febs open bio
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.718
H-Index - 31
ISSN - 2211-5463
DOI - 10.1002/2211-5463.12520
Subject(s) - escherichia coli , metallothionein , phytochelatin , heterologous expression , complementary dna , biochemistry , metalloprotein , arabidopsis thaliana , heterologous , amino acid , chemistry , peptide sequence , arabidopsis , biology , microbiology and biotechnology , recombinant dna , gene , enzyme , glutathione , mutant
Members of the metallothionein ( MT ) superfamily are involved in coordinating transition metal ions. In plants, MT family members are characterized by their arrangement of Cys residues. In this study, one member of the MT superfamily, Cs MTL 3 , was characterized from a complementary DNA ( cDNA ) library from young cucumber fruit; Cs MTL 3 is predicted to encode a 64 amino acid protein with a predicted molecular mass of 6.751 kDa. Phylogenetic analysis identified it as a type 3 family member as the arrangement of N‐terminal Cys residues was different from that of MT‐like 2. Heterologous expression of Cs MTL 3 in Escherichia coli improved their heavy metal tolerance, particularly to Cd 2+ and Cu 2+ , and led to increased uptake of Cd 2+ and Cu 2+ ; increased uptake was also observed for cells expressing Arabidopsis thaliana metallothionein 3 (At MT 3) and phytochelatin‐like ( PCL ), with greatest uptake in PCL ‐expressing cells. These findings demonstrate that Cs MTL 3 can improve metal tolerance, especially for Cd 2+ ions, when heterologously expressed in E. coli , and suggest that the composition and arrangement of N‐terminal Cys residues are associated with binding capacity and preference for different metal ions.