Influenza A virus H3N2 neuraminidase (H3N2 NA)

Influenza A H3N2 neuraminidase is a critical surface glycoprotein enzyme found on the envelope of the H3N2 subtype of the influenza A virus. Its primary biological function is to catalyze the hydrolysis of terminal sialic acid residues from host cell receptors and newly formed virions, which is essential for the release of progeny viruses from infected cells and their subsequent spread through the respiratory tract. By preventing the aggregation of viral particles and allowing them to penetrate the mucus layer of the airway, neuraminidase plays a vital role in the viral life cycle and pathogenesis of seasonal influenza. In the context of pharmacology, the active site of this enzyme is the primary target for neuraminidase inhibitors such as oseltamivir and zanamivir. These drugs mimic the transition state of the sialic acid substrate, binding tightly to the conserved residues within the active site to block enzymatic activity. Effective inhibition of H3N2 neuraminidase significantly reduces viral shedding and alleviates the severity and duration of flu symptoms, although the emergence of drug-resistant mutations remains a significant clinical challenge.

Other names

NeuraminidaseSialidaseNAExoneuraminidaseInfluenza A virus (A/Hong Kong/1/1968(H3N2)) neuraminidase

Neuraminidase inhibitors act as transition-state analogues that bind competitively to the highly conserved active site of the enzyme, preventing the cleavage of terminal sialic acid residues from host cell receptors and viral glycoconjugates, thereby trapping progeny virions at the host cell surface and inhibiting further viral spread.