Neuraminidase protein of Influenza A virus subtype H5 (NA (H5N1))

The **neuraminidase protein of Influenza A virus subtype H5** (commonly designated as N1 in H5N1) is a surface glycoprotein and enzyme integral to the viral envelope. It assembles as a homotetramer with a mushroom-like structure comprised of approximately 470 amino acids per subunit[1][4][5]. The protein catalyzes the removal of terminal sialic acid residues from host cell glycoproteins and glycolipids, a critical function that facilitates the release of newly formed virions from infected cells, prevents viral aggregation, and enables efficient viral spread[3][5]. Its activity counterbalances hemagglutinin's binding activity, maintaining an essential functional balance for optimal viral infectivity[5]. The neuraminidase's structure includes a cytoplasmic tail, transmembrane domain, stalk, and a catalytic globular head where the active site is located[1][5]. The enzymatic site is targeted by antiviral drugs (neuraminidase inhibitors), which block virus propagation by preventing virion release[3][5]. The NA protein is a major antigenic determinant and subject to frequent genetic variation, contributing to its role in immune escape and pandemic potential[3][4]. Resistance to neuraminidase inhibitors and antigenic changes due to mutation or reassortment are important clinical and public health concerns[4][5].

Other names

Neuraminidase (NA) of Influenza A virus (H5N1)Influenza A neuraminidase N1Sialidase (virus-associated)N1 protein

Inhibition of enzymatic activity prevents the cleavage of sialic acids, blocks viral release, and halts infection spread