Influenza virus neuraminidase (H7 subtype) (NA)

Influenza virus neuraminidase is a tetrameric surface glycoprotein and enzyme essential for the replication cycle of the influenza virus. It functions as a sialidase, catalyzing the cleavage of terminal sialic acid residues from glycoproteins and glycolipids on the host cell surface and the viral envelope (Source: UniProt). This enzymatic activity is critical for the release of newly formed virions from infected cells, preventing their entrapment in mucus and their aggregation on the cell surface. In the context of H7 influenza strains, such as the avian-origin H7N9, the neuraminidase (typically the N9 subtype) is a key antigenic component used in the formulation of matching vaccine strains to elicit protective immunity (Source: CDC). It is also the primary target for neuraminidase inhibitors like oseltamivir and zanamivir, which competitively bind to the enzyme's active site to block viral spread. Therapeutic challenges include the emergence of resistance-conferring mutations, such as the R292K substitution, which can significantly reduce drug efficacy. Understanding the structure and function of the H7-associated neuraminidase is vital for both seasonal and pandemic preparedness.

Other names

SialidaseExo-alpha-sialidaseNeuraminidaseNAN9 neuraminidase

Neuraminidase inhibitors competitively bind to the active site of the enzyme, preventing the cleavage of terminal sialic acid residues on host cell receptors. This action traps progeny virions on the surface of the infected cell, thereby inhibiting the spread of the virus to uninfected cells (Source: PubMed PMID: 22226136).