Influenza A virus neuraminidase (NA) (NA)

Influenza A virus neuraminidase (NA) is a tetrameric type II transmembrane glycoprotein and enzyme essential for the influenza virus life cycle (UniProt: P03468). It functions as a sialidase, specifically cleaving alpha-ketosidic linkages between terminal sialic acid residues and adjacent sugar residues on host cell surfaces and viral progeny (PubMed: 22226115). This enzymatic activity is indispensable for the release of newly synthesized viruses from infected cells, as it prevents the sequestration of virions by host sialic acids. Furthermore, NA aids viral movement through the respiratory tract by degrading sialic acid-containing mucins in the mucus layer (NCBI: PMC3347517). In the context of vaccines and therapeutics, NA is a key antigen and the primary target for several FDA-approved antiviral drugs, including oseltamivir and zanamivir (DrugBank: DB00198). These drugs act as competitive inhibitors that mimic the transition state of sialic acid cleavage, effectively trapping the virus on the host cell surface and limiting further infection (PubMed: 11056646). However, the rapid evolution of the virus leads to mutations like H274Y, which can significantly reduce drug efficacy and necessitate continuous monitoring (CDC: Influenza Antiviral Drug Resistance).

Other names

SialidaseExo-alpha-sialidaseNAN-acetylneuraminate glycohydrolaseInfluenza A NA

Competitive inhibition of the neuraminidase enzyme, which prevents the cleavage of terminal sialic acid residues on host cell receptors and viral glycoproteins, thereby blocking the release of progeny virions and limiting viral spread (PubMed: 11056646; DrugBank: DB00198).