from Dahai Luoa, Siew Pheng Lim and Julien Lescar writing in Molecular Virology and Control of Flaviviruses:
The non-structural protein 3 (NS3) of flaviviruses is the second most conserved amongst the viral proteins. It bears a molecular mass of 69 kDa and is endowed with multiple functions including proteolytic processing, nucleic acid duplexes unwinding, nucleoside triphosphatase (NTPase) and RNA nucleoside 5' triphosphatase (RTPase). Besides these enzymatic activities which are essential for replication of viral genomic RNA, this protein also participates in other aspects of the viral life cycle. Numerous crystal structures of apo- and ligand-bound 3D structures for the protease and helicase domains of NS3, as well as for the full-length NS3 polypeptide (NS3FL) have been determined, providing insight at the atomic level into its various enzymatic activities. In this chapter, we summarize recent progress published regarding the function and structure of this fascinating viral non-structural protein including its recently uncovered dynamic properties.
Further reading: Molecular Virology and Control of Flaviviruses