This entry contains printable models of three molecules that help explain how influenza neuraminidase works, and how antiviral drugs inhibit it. Neuraminidase is a viral surface enzyme that removes terminal sialic acids from carbohydrate chains, helping newly formed influenza viruses detach from infected cells and spread.

The models include:

• Sialic acid (N-acetylneuraminic acid; Neu5Ac): The terminal sugar recognized and cleaved from carbohydrate chains by neuraminidase. This model represents a free sialic acid molecule observed in the enzyme’s active site.

• Oseltamivir carboxylate: The active metabolite of oseltamivir, the drug marketed as Tamiflu. It binds within neuraminidase’s catalytic pocket and inhibits its activity.

• Zanamivir: The antiviral drug marketed as Relenza, which also occupies the catalytic pocket and inhibits neuraminidase.

Together, these models allow hands-on comparison of molecular shapes and functional groups, illustrating how drugs can mimic features of a naturally recognized molecule while blocking an enzyme’s function. They can be used alongside neuraminidase models to demonstrate molecular recognition, competitive inhibition, and structure-based drug design.

Structural coordinates were derived from PDB entries 2BAT (sialic acid), 2HU4 (oseltamivir carboxylate), and 3B7E (zanamivir) and modeled using UCSF ChimeraX 1.12 and the "heteroatom" coloring scheme.

All oxygen atoms are red and nitrogen atoms are blue. Carbon atoms are colored differently for each molecule: sialic acid, green; oseltamivir, pink; zanamivir, gold.