Abstract FR:

The structures of complexes between Human Rhinovirus (HRV) serotype 2 (a minor group HRV) and soluble fragments of its cellular receptor VLDL-R have been determined by cryo-electron microscopy and 3-D reconstruction techniques. The receptor is seen to bind on an annulus on the small star-shaped dome on the icosahedral 5-fold axis. This is in sharp contrast to the major group of HRVs, where the receptor ICAM-1 binds in a depression around the 5-fold axis. These different modes of binding are correlated with differences in the mechanism of viral entry. Only two of the eight ligand binding repeats of the VLDL-R bind to HRV2. The third repeat is strongly bound to polar residues of the HI- and BC- loops of the viral protein VP1, while the second repeat is more weakly bound to the neighbouring VP1. Since the receptor molecule can bind to two adjacent copies of VP1, we suppose that the bound receptor "staples" the VP1s together and must be detached before release of the RNA, can occur.