Rice is a staple crop that is consumed by half of the worlds population. Paddy rice is highly prone to heavy metal toxicity. Low level of heavy metals in rice plant is beneficial for plant growth but its excess can affect the growth of the plant. Consumption of rice contaminated with heavy metal has a potential health risk to human population. Metallothionein (MT) is a metal binding proteins that comes under a class of conserved evolutionary protein molecules. It plays an essential function in the detoxification of heavy metals and homeostasis. Metals with relatively high densities, atomic weights, or atomic numbers are known as heavy metals. Cadmium (Cd), arsenic (As), chromium (Cr), lead (Pb) and zinc (Zn) are highly reactive and toxic to living cells. Plants have described two basic mechanisms such as chelation and sequestration of heavy metals by ligands to counter this problem. The two best-characterized heavy metal-binding ligands in plant cells are the phytochelatins and metallothionein. In the current study, we have generated the three dimensional structure of rice MT protein, identification of active sites of metallothionein and docking study was performed. Homology model of the metallothionein was designed through Phyre2 server. Heavy metals were docked with the metallothionein. The docking analysis and active sites were predicted through iGemDock software. The stable homology structure of the metallothionein was modelled and binding pockets were analyzed. This analysis of binding pocket will help in the in vitro study of metallothionein protein and understanding its role in metal detoxification.
Key words: Metallothionein, Homology modelling, Docking, Binding Pocket.