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 gene expression analysis 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 amino- terminal from OsMTI-1b isoform belonging to type P1 rice MT and production of mutant form of C-OsMTI-1b and investigation of effect of that on tolerance of cadmium, nickel, zinc and copper stress compared to its wild type ( OsMTI-1b ). For production C-OsMTI-1b gene fragment from OsMTI-1b gene, specific primer was designed and C-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 strain Rosetta (DE3). By inducing of protein production by Isopropyl-?-D-thiogalactopyranoside (IPTG), the considerable amount of GST-C-OsMTI-1b protein produced. The tolerance of strains, producing GST-OsMTI-1b, GST-N-OsMTI-1b and GST-C-OsMTI-1b protein, to heavy metals were investigated by plotting their growth curve in presence of CdCl2.H2O, NiCl2.6H2O, ZnSO4.7H2O and CuSO4 salts and by measurement of the amount of decreased of cadmium in culture medium by using atomic adsorption spectroscopy (AAS). Recombinants proteins were purified and the metal-binding ability of GST-C-OsMTI-1b protein was compared to its wild form (GST-OsMTI-1b) and GST-N-OsMTI form. Comparison of metal-binding ability was performed by investigation of spectroscopic characteristics and reaction with Ellman's reagent. The results of growth curve of mutated strain to metals showed that the tolerance of bacteria cells to Cd, Ni, Zn and Cu increased due to the expression of GST-C-OsMTI-1b protein. The measurement of amount of decreased cadmium metal from culture medium using atomic adsorption spectroscopy showed that the mutated strain can absorb 4.63 ppm of Cd from culture medium. Amount of absorbed Cd in the producing GST-OsMTI-1b and GST-N-OsMTI-1b proteins, were 4.93 and 2.44 ppm respectively. Comparisons of amount of absorbed metal on these strains have shown that the metal absorption capacity in strain, producing GST-C-OsMTI-1b protein, Due to more compact structure of this mutant, its near to strain producing GST-OsMTI-1b protein. Investigation of binding capability of GST-C-OsMTI-1b protein to Cd, Ni and Zn in in vitro condition were performed by reaction of mutated protein with Ellman's reagent.So, Apo proteins were prepared by acidification method and then these proteins were exposed to to saturated concentrations of Cd, Ni and Zn ions. The results showed that the initial rate of reaction of Ellman's reagent with apo GST-C-OsMTI-1b protein was more than protein containing Cd, Ni and Zn. These results showed that the GST-C-OsMTI-1b protein can absorb these metals. Also study on spectroscopic characteristics of mutant protein confirmed results of absorption of Cd, Ni, Zn and Cu by this protein. Generally the results showed that the mutated protein even without of amino- terminal can bind to metal. These results suggest that the C-terminal Cys-rich region in of OsMTI-1b can bind metals independent of N-terminal. Keywords : Rice, Metallothionein, terminal Cys-rich region, binding ability