Neuraminidase protein of influenza A virus H3N2 subtype (NA)

Neuraminidase protein of influenza A virus H3N2 subtype is a type II transmembrane glycoprotein enzyme displayed as homotetramers on the viral envelope[2][3][7][8]. It cleaves terminal sialic acid residues from host cell surface glycoproteins and glycolipids, facilitating the release of progeny virions from infected cells and preventing aggregation of viral particles[3][5][7][8]. Alongside hemagglutinin (HA), NA is one of the major surface antigens of the influenza A virus and evolves rapidly to evade the immune response[1][5]. There are nine subtypes of influenza A neuraminidase (N1–N9), of which N2 is present in the H3N2 subtype[3][5][8]. Neuraminidase is an established drug and vaccine target, with inhibitors such as oseltamivir and zanamivir used clinically to reduce disease severity and spread[3][5][8]. Functionally, its balance with HA is critical for viral fitness, optimal infectivity, and transmissibility[7][8]. NA is also a key antigenic determinant in both natural infection and vaccine-induced immunity, but continuous mutation leads to antigenic drift and emerging resistance to antivirals[1][8]. Additional structural features include a globular "head" domain (containing the enzymatic active site), a stalk region, and a membrane-anchoring domain[5][8]. NA's biological and therapeutic significance is underscored by its roles in viral replication, host specificity, drug resistance, and as a predictive marker for antiviral strategies[3][7][8].

Other names

Neuraminidase (NA)Influenza A virus neuraminidaseN2 neuraminidaseSialidase

Competitive inhibition of the neuraminidase active site by neuraminidase inhibitors, blocking sialic acid cleavage and preventing release of new virus particles