inhibitors for protease such as papain, subtilisin and one from sindbis virus capsid might share some similarities as they all are cysteine proteases. if ns2-3 protease does share important similarities with other cysteine proteases, it might be possible to propose a model for inhibition of the ns2-3 cysteine protease activity, which might be able to offer a permissible approach to a robust vaccine for in-vitro animal model studies.