Figure 1.
Action of inhibitors on a virus. The free virus (a) has surface spike glycoproteins (represented as black rectangles) each of which may be blocked by binding heparin molecules (b) to give a V.I complex (c) which can no longer bind to the cellular receptors (d) on the surface of the host cell (e). Free virus (f) can bind to the cellular receptors allowing entry (k) of the nucleocapsid core (black triangle) to the cell. Inhibitors such as zinc oxide tetrapods (g) can also bind to the free virus (a) to give a V.I complex (h) which could still theoretically bind to the host cell (i) with subsequent entry (k) of the viral core into the host cell (e). Binding could be prevented by a second inhibitor such as heparin (j). Once in the cell the viral main protease (Mpro) is synthesized from RNA in the nucleocapsid core. Mpro is inhibited by an inhibitor I (l).