H9N2 influenza virus neuraminidase (NA)

The H9N2 influenza virus neuraminidase is a critical surface glycoprotein of the H9N2 avian influenza virus, which is prevalent in poultry and a significant source of zoonotic infections in humans. As an exo-alpha-sialidase (EC 3.2.1.18), its primary biological role is to catalyze the cleavage of terminal sialic acid residues from host cell receptors and newly synthesized viral glycoproteins. This enzymatic activity is essential for the detachment of progeny virions from the host cell membrane, preventing viral aggregation and facilitating the spread of the infection to adjacent cells. Additionally, the neuraminidase assists the virus in penetrating the respiratory mucus layer by degrading sialic acid-containing mucins. Due to its indispensable role in the viral life cycle, it serves as the primary target for neuraminidase inhibitors such as oseltamivir, zanamivir, and peramivir. These drugs act by competitively binding to the enzyme's conserved active site, effectively halting viral replication. However, the emergence of drug-resistant mutations, notably R292K and E119V, poses a significant threat to treatment efficacy and emphasizes the need for continuous genomic surveillance of circulating H9N2 strains.

Other names

Viral neuraminidaseSialidaseExo-alpha-sialidaseN2 neuraminidaseNeuraminidase (H9N2)

Competitive inhibition of the viral neuraminidase active site, which prevents the cleavage of terminal sialic acid residues on host cells and viral glycoproteins, thereby halting the release and spread of newly formed virions.