FIG 5.

Stereo pairs of electron density of the inner surface of the capsid at the quasi-6-fold axis. The top panels show the density of the crystallographic structure of CNV at the quasi-6-fold axis (5). The mauve sphere in the center represents the putative zinc ion chelated by three icosahedrally related C-chain His residues. Subsequent panels show the density of the cryo-EM structure of the wild-type (wt) CNV under native conditions (FSC1/2 of 6.8 Å) and under swollen conditions (FSC1/2 of 9.9 Å), as indicated. The model shown at the annulus is from the native, wild-type structure even though the C subunits are displaced from the quasi-6-fold axis due to the swelling. The bottom panels show the cryo-EM structure of the P73G annulus under native conditions (FSC 0.143 of 4.2 Å and FSC1/2 of 4.5 Å). While the density of the subunits around the annulus is well defined, the metal binding area at the annulus is badly disordered.