West Nile virus NS2B-NS3 protease (WNV NS2B-NS3pro)

The West Nile virus (WNV) NS2B-NS3 protease is a heterodimeric enzyme complex essential for the replication and maturation of the virus, which belongs to the Flaviviridae family [1]. The complex consists of the N-terminal domain of the non-structural protein 3 (NS3), which contains the catalytic triad (His51, Asp75, Ser135), and a specific hydrophilic segment of the NS2B protein that serves as an indispensable cofactor for catalytic activity and proper folding [2]. This serine protease is responsible for the post-translational cleavage of the viral polyprotein at several junctions, specifically at the NS2A/NS2B, NS2B/NS3, NS3/NS4A, and NS4B/NS5 sites [3]. By processing these sites, the protease releases functional non-structural proteins that are required to form the viral replication complex [4]. Because the virus cannot replicate without this proteolytic activity, the NS2B-NS3 protease is considered a primary target for the development of antiviral drugs to treat West Nile fever and its severe neurological manifestations, such as encephalitis and meningitis [5]. Currently, there are no FDA-approved inhibitors for this target, though research into small-molecule and peptidomimetic inhibitors is ongoing [6]. Key challenges in drug development include ensuring high selectivity to avoid inhibiting host cell proteases and achieving sufficient penetration of the blood-brain barrier to treat neuroinvasive infections [7].

Other names

NS2B-NS3 serine proteaseNS3 proteaseWNV NS3 protease complexFlavivirus NS2B-NS3 proteaseNS3/NS2B protease

Inhibition of the NS2B-NS3 protease prevents the cleavage of the viral polyprotein into functional non-structural proteins, thereby blocking viral replication and assembly [3, 4].