---

PFU DNA polymerse shows  the lowest error rate in Polymerase Chain Reaction (PCR) but it seperates from DNA  after about 20 nucleotides  add  to the end of primer strand. The research purpus is processivity improvement of PFU DNA polymerase by means of rational design and point mutation due to lowest enthropy and enthalpy costs. so DNA polymerases in B family with high processivity were selected and their structures and sequences were compared with PFU DNA polymerase then an optimized mutation was induced . Native form and mutant were simulated for 100 ns and the trajectories were analyzed. ΔG_binding was calculated by g_mmpbsa tool and proved that the mutant shows a robust affinity .