Bioaccumulation of Arsenic in Recombinant Escherichia coli Expressing Human Metallothionein

摘要

The recombinant Escherichia coli (E. coli) expressing human hepatic metallothionein_IA (hMT_IA) was constructed for bioaccumulation of Arsenic (As). The gene sequence of hMT_IA was modified for codon preference of E coli and synthesized using chemical method. The vector of pGEX_4T_1 was used and hMT_IA was expressed as the fusion protein with glutathione S-transferase (GST) tag. The bioaccumulation capability of arsenite compounds As(III) of the recombinant E. coli increased more than 3-fold from 76.3 to 319.6 mu g/g dry cells compared with the control. The conditions of 50 mu M of As(III) and low pHs were optimal for As(III) bioaccumulation. The heavy metals of Cd, Hg, and Zn inhibited As(III) bioaccumulation. The bioaccumulation reached 70% of the saturated value within 1 h. The recombinant E. coli will be useful in bioremediation of arsenic or other kinds of heavy metal contaminated water.