Study On The Interactions Of Influenza A Virus NS1 Protein With CPSF30 And Vitural Screening For Its Inhibitor

Influenza A virus is the cause and a major pathogens of influenza.Genetic recombination could occur frequently in Influenza A virus,which could result in the constantly appearance of new types of virus.Especially in recent years,new types of avian influenza virus,such as H7N9 and H10N8,are appearing succession in a short period of time,which makes the prevention and control situation of the Influenza virus becomes more and more severe.Furthermore,Influenza A virus have a high mutation rate,this led to that humans can not get lasting immunity by vaccination.Therefore,the existing chemical drugs and influenza virus vaccines are difficult to effectively prevent and treat influenza.This makes the research and development of new anti-influenza virus drugs more urgent.With the extensive research on the pathogenesis mechanism of influenza virus,we have found a number of potential drug targets for development of new anti-influenza drugs.One of these is the CPSF30 binding site of NS1 protein effector domain,which could suppress the normal function of CPSF30 factor of the viral host cell and plays a key role in inhibition of host antiviral response.On the other hand,Chinese herbal medicine is a very good antiviral agent,even in the case of treatment of the virus with drug-resistant mutations.Chinese herbal medicine has played an important role in the prevention and treatment of influenza.It is essential to identify the active ingredients from Chinese herbal medicine use modern biotechnology.In this study,we firstly analyzed the structural features of CPSF30 binding site of NS1 protein effector domain and the dynamics characteristic of the binding between NS1 and CPSF30 by multiple sequence alignment,molecular dynamics simulation and binding free energy calculation.The results suggest that the CPSF30 binding site on NS1 protein is a highly conserved hydrophobic pocket and hydrophobic interactions is the main driving force of the formation of the F2F3-NS1 complex.By employ the molecular dynamics simulation of different type of NS1 proteins,we also found that the formation of NS1 dimer and NS1-F2F3 complexcould increase the stability of NS1 protein which is mainly caused by the residues in the NS1-CPSF30 binding interface.Then,the Maybridge Screening library,NCI Plated Compounds library and TCM Database@Taiwan were used as small molecule compound library to find potential inhibitors for NS1 protein CPSF30 binding site by molecular docking based virtual screening.Six potential inhibitors(NCI102895,NCI1320211,NCI1664344,NCI186958,NCI186220,NCI 166225)were selected from approximately 200000 compounds from Maybridge Screening library and NCI Plated Compounds library.Four potential inhibitors(10227,31674,30256,27405)were selected from the TCM Database@Taiwan.And then,the interacting modes between potential inhibitors and NS1 protein were analyzed by Pymol.The results showed that hydrophobic effect is the main interaction between potential inhibitors and NS1 protein,and some hydrogen bonds could be found between the potential inhibitors and some hydrophilic amino acid in the edge of the binding pocket.Furthermore,the dynamics characteristic of the binding between NS1 and two inhibitors(31674 and 30256)were particular evaluated by the molecular dynamics simulation and binding free energy calculation.It is suggested that these inhibitors could be modified to possess higher affinity.In this study,we detailed analyzed the interaction mode between NS1 and CPSF30,the results a theoretical basis for the designing of anti-influenza virus drugs based on the NS1 protein CPSF30 binding site.We also found some small molecule compounds that could inhibit the influenza A virus,and we also found some characteristics of the interaction between a number of small molecule compounds with NS1 protein,which made a good attempt for the development of new anti-influenza A virus drugs.