Influenza A virus neuraminidase N1 (N1)

Influenza A virus neuraminidase N1 is a critical surface glycoprotein and enzyme found on the envelope of various influenza A virus subtypes, including H1N1 and H5N1 (UniProt). It functions as a sialidase (EC 3.2.1.18), specifically catalyzing the removal of terminal sialic acid residues from viral and cellular glycoconjugates (NIH). This activity is essential for the release of newly formed virions from the host cell surface, as it prevents the viral hemagglutinin from rebinding to the cell and avoids the aggregation of progeny viruses (Britannica). Beyond its role in viral egress, N1 also facilitates the movement of the virus through the respiratory tract by cleaving sialic acids in the protective mucus layer (Frontiers in Microbiology). As a primary therapeutic target, N1 is inhibited by several antiviral drugs, such as oseltamivir and zanamivir, which mimic the transition state of the sialic acid cleavage reaction to block the enzyme's active site (NIH). However, the clinical utility of these inhibitors is frequently challenged by the emergence of resistance mutations, most notably the H275Y substitution, and the continuous antigenic evolution of the virus (PubMed).

Other names

NeuraminidaseSialidaseNAN1 subtypeReceptor-destroying enzymeExosialidase

Neuraminidase inhibition; the drugs act as transition-state analogs that bind to the enzyme's active site, preventing the cleavage of sialic acid residues and thereby trapping progeny virions on the host cell surface to prevent further infection (NIH, Britannica).