Abstract

HCV infection has been declared as a principal health problem in more than 200 million individuals throughout the world. It is a positive-stranded RNA virus and classified as a hepacivirus of the flaviviridae family. Unlike other viral infections Hepatitis C Virus even with its high replication rate can stick within a human host for decades without any irritation or liver damage. Estimated 10 million people are believed to be infected by HCV alone in Pakistan. Eventually the infection causes severe complications in 60 to 70% of patients such as cirrhosis, fibrosis, liver failure and hepatocellular carcinoma. Prior to the development of HCV protease inhibitors combination therapy, patients with HCV infection were treated with pegylated interferon-α and ribavirin. The adverse side effects associated with this type of treatment such as anemia, flu-like symptoms, depression, gastrointestinal symptoms, fatigue and cutaneous reactions may lead to the discontinuation of treatment in certain number of patients. The growth in scientific knowledge of HCV life cycle and its replication leads to the development of inhibitors of HCV proteases. A polyprotein precursor encoded by HCV RNA genome containing structural proteins capsid (C), membrane (prM), envelope (E) and nonstructural (NS) proteins (NS1, NS2a, NS2b, NS3, NS4a, NS4b, NS5). NS3 protease when activated by NS4A causes the cleavage of polyprotein producing the non-structural proteins 4A, 4B, 5A, 5B and is thus very supportive in the replication of virus. That is why NS3/4A protease is a significant emerging target for the treatment of HCV infection. NS3 associates to the ER membrane only in the presence of NS4A. Main actively conserved protein target families can be distinguished by a simple look at physicochemical properties (molecular weight, log P, polar surface area, H-bond donor and acceptor counts) of their cognate ligands (Morphy, 2006). One can thus easily imagine that more sophisticated descriptors can be used to predict a global target profile for any given compound, provided that targets to be predicted are sufficiently well described by existing ligands. In this study we resulted finally in the Silico generation of a sophisticated descriptor for the computer aided target fishing of Identification of hybrid KPQRK/TKRNT peptide mimetic Leads for a potential and simultaneous Inhibition of Protease and Helicase Activities to HCV NS3/4A Protease.