Neuraminidase protein of influenza A (NA)

The neuraminidase protein of influenza A is a viral surface glycoprotein essential for influenza virus replication and spread. Structurally, it is a homotetrameric enzyme with each monomer consisting of approximately 470 amino acids, forming domains including cytoplasmic, transmembrane, stalk, and catalytic head. Functionally, neuraminidase cleaves the α-ketosidic bond between terminal sialic acid and adjacent sugar residues on host cell glycoproteins, facilitating the release of newly formed virions and preventing viral self-aggregation. It also assists in viral movement through mucus and maintains functional balance with hemagglutinin for efficient infection. The gene encoding the NA protein is highly variable, with nine known subtypes in influenza A (N1-N9), crucial for subtype classification (e.g., H1N1, H5N1). Neuraminidase is a major antiviral drug target; inhibitors block viral egress and are first-line treatments for influenza infection, but resistance can emerge through mutations in the enzyme’s active site.

Other names

Influenza A neuraminidaseViral neuraminidaseSialidase (EC 3.2.1.18)NA protein

Enzyme inhibition: Drugs bind to neuraminidase’s active site, blocking cleavage of sialic acid residues, preventing viral release from infected cells, halting viral replication and spread.