The Study Of Inhibitors For Yellow Fever Virus NS2B-NS3 Protease

Yellow Fever virus(YFV)originated in Africa and was the first human virus to be isolated.The mosquito is its main carrier of transmission.This virus can cause typical viral hemorrhagic fever,which can lead to death in severe cases.At the beginning of 2017,a wide range of yellow fever epidemics were reported in areas such as Angola,Congo and uganda.This is the first outbreak of the virus in these areas in the past 30 years,and more than a dozen cases have been confirmed in various regions such as China.The “re-emergence” of YFV has aroused people’s extensive attention.Along with the rapid development of urbanization and transportation,the risk of YFV spreading will also increase,and the probability of people’s illness will also increase greatly.However,there is no specific drug to treat YFV infection,so the development of anti-YFV drugs is urgent.Like other flaviviruses,YFV protease is a typical serine protease located at the N-terminal one-third of non-structural protein 3(NS3),requiring NS2 B for activation.It processes the viral genome-encoded polyproteins,hydrolyzing them into proteins that function independently,thereby can participating in viral assembly and genome replication.Therefore,NS2B-NS3 protease plays an indispensable role in the process of virus replication and is a very potential drug target.In this work,we used YFV NS2B-NS3 protease as a research object,using prokaryotic expression system and various purification methods obtained high-purity protein and measured its enzyme activity using fluorescent substrate.At the same time,a sensitive drug screening system was established.Not only the inhibition constant of the serine protease inhibitor Aprotinin was determined,but also more than 3,000 small molecules in the compound library were screened,and three small molecules with inhibitory effects were found.Finally,the inhibition type and inhibition constant were determined for one of the more effective inhibitors,cetylpyridinium chloride.The above studies not only screened new lead compounds for the development of anti-YFV drugs,but also provided a basis for further study of the structure-activity relationship between proteases and compounds.