Metallothioneins (MTs) are a Cys-rich protein with low molecular wight (5-10 KDa) that can bind heavy metals via the thiol groups of Cys residues. More studies on plant MTs has been limited on the investigation of expression of these genes in various tissues. So far a little researches on role and structure of MTs has been done. The aim of this study was elimination the carboxy- terminal from OsMTI-1b isoform belong to type 1 rice MT and production of mutant form of N-OsMTI-1b and investigation of effect of that on tolerance of cadmium’s and nickel’s stress compared to its wild type ( OsMTI-1b ). For production N-OsMTI-1b gene fragment from OsMTI-1b gene, specific primer was designed and N-OsMTI-1b gene was amplified by PCR. The Amplified fragment was cloned in pET41a expression vector. The Colony was confirmed by sequencing and then the producing construct was transferred into expression host, Escherichia coli Rosetta (DE3). By inducing of protein production by Isopropyl-?-D-thiogalactopyranoside (IPTG), the considerable amount of GST-N-OsMTI-1b protein produced. The tolerance of strains, producing GST-OsMTI-1b and GST-N-OsMTI-1b protein, to heavy metals were investigated by plotting their growth curve in presence of CdCl 2 and NiCl 2 salts and by measurement of the amount of decreased metals in culture medium by using atomic adsorption spectroscopy (AAS). Recombinants proteins were purified and the metal-binding ability of GST-N-OsMTI-1b protein was compared to its wild form (GST-OsMTI-1b). Comparison of metal-binding ability was performed by investigation of spectroscopic characteristics and reaction with Elman reagent. The results of growth curve of mutated strain to metals showed that the tolerance of bacteria cells to Cd and Ni increased due to the expression of GST-N-OsMTI-1b protein. The measurement of amount of decreased metal from culture medium using atomic adsorption spectroscopy showed that the mutated strain can absorb 7.4% of Cd and 3.63% of Ni from culture medium. Amount of absorbed Cd and Ni in the strain ,producing GST-OsMTI-1b protein, were 11.71% and 8.21% respectively. Comparisons of amount of absorbed metal on two strains have shown that the metal absorption capacity in strain, producing GST-N-OsMTI-1b protein, Due to elimination of carboxy- terminal was low. Investigation of binding capability of GST-N-OsMTI-1b protein to Cd and Ni in in vitro condition were performed by reaction of mutated protein which producing in presence and absence of metal with Elman reagent. The results showed that the initial rate of reaction of Elman reagent with Apo GST-N-OsMTI-1b protein was more than protein containing Cd and Ni. But due to low amount of free thiol groups, this rate was lower than GST-OsMTI-1b protein. These results showed that the GST-N-OsMTI-1b protein can absorb these two metals. Apo proteins were prepared by acidification method and then these proteins were exposed to Cd and Ni. Reaction of these proteins with Elman reagent confirmed that obtained results from in vitro condition . Also study on spectroscopic characteristics of mutant protein confirmed results of absorption of Cd and Ni by this protein. Generally the results showed that the mutated protein even without of carboxy- terminal can bind to metal. These results indicated that the amino- terminal independently of carboxy- terminal can bind to metal. Keyword : Rice, Metallothionein, Heavy Metals, Elman Reagent, Protein Expression