Published Paper Details:

A metallothionein Type II gene was previously isolated from Leucaena leucocephala, a leguminous species and cloned into pET28a(+) vector and moved into E. coli BL21 strain for protein expression. 0.1mM IPTG was used for induction of enhanced expression and total protein content was loaded onto 12% SDS gel. Purification was done using NI-NTA Affinity Column Chromatography and loaded onto 18% SDS gel. In the former, slight increase in band intensity was seen between 5-10 kDa whereas in the purified samples, bands were observed at 7-8 kDa which is congruent to the fact that the predicted molecular weight of the Leucaena MTII protein is 7.6 kDa. Different concentrations of Cu, Cd and As were used to analyze the efficiency of recombinant BL21 cells in combating heavy metal toxicity. OD values taken at intervals of 3, 5 and 7 hours and overnight shows marked decrease in growth rate of control non-recombinant cells whereas growth rate in the recombinant cells are consistently same for all. These findings can lead to the conclusion that heterologous expression of MTII gene from Leucaena in other living systems is highly effective in protection against heavy metal toxicity.