Several million individuals around the world were found to be infected by Hepatitis C Virus (HCV). Many efforts have been taken to find more potent and efficient drug. After several clinical analyses the drugs namely telaprevir, danoprevir, vaniprevir & MK-5172 were evolved to inhibit the viral NS3/4A protease. However, the efficiency of the drug mainly relies on resistance factor. For instance single-site mutation at protease residue R155 confers resistance to most of the inhibitors in clinical trials. Thus knowledge about molecular basis of drug resistance is important to find perfect drug that can retain activity against resistant viral variant (R155K). Hence in the present study, we employed molecular docking and normal mode analysis to infer the mechanism of drug resistance. Furthermore, we examined the stability of the structures with the aid of salt bridge and stabilizing residues (SRide) analysis. We hope that the results obtained in the study certainly helpful for the better understanding of NS3/4A protease-MK 5172 interacting pattern.