Part:BBa_K3076100

Coding sequence of metallothioneins (MT) gene from Corynebacterium glutamicum

Metallothioneins (MT) are proteins made of 61-68 amino acids with a small molecular weight. It is found in almost every known organism, from bacteria to humans. Due to this ubiquity, it minimizes the gene toxicity effect when we choose it as the ectopic expression target.

MT contains many cysteine groups which were reported to be responsible for chelating a wide range of metal ions such as cadmium, lead, copper, and mercury, etc. Nevertheless, MT from different species showed different affinity towards different metal ions.

Literature reported that MT protein from Corynebacterium glutamicum (CgMT) shows strong binding affinity towards divalent cations, such as Zn2+ and Pb2+. [1] Since our project used Cu2+ as a model for the metal pollutants, we decided to explore the plausibility of using CgMT to increase the metal accumulation ability of E. coli.

This part was synthesized into pET151/TOPO vector for the ectopic expression in E. coli BL21. The results showed that the CgMT transformant absorbed significantly more copper ions (~15%) in the culture medium when compared with non-induced control and empty vector control.