Biology Reference
In-Depth Information
Fig. 8.
Externalization of the N-terminus of VP1 and exit of the RNA.
A schematic drawing of the virus (
left
) illustrates the positions of 2, 3, 5, and
pseudo three-fold axes (yellow triangle) and of the viral canyon; VP1, blue;
VP2, green; VP3; red. Density maps of native HRV2 were calculated from the
X-ray data (red) and superimposed onto the cryo-EM reconstructions of
empty HRV2 particles (blue). Regions in blue in the superposition indicate
where the empty particle is enlarged with respect to the native virus. This is
particularly pronounced at the five-fold axes (
right
). Possible points of exter-
nalization of the N-terminus of VP1 are indicated. Cryo-EM of empty HRV14
capsids suggests exit at the five-fold axis, whereas in a complex between empty
HRV3 and sICAM-1 VP1 appears to externalize at the pseudo three-fold axis.
Neither of the empty major group HRV shows enlargement of the VP3
β
-cylinder as seen in HRV2. RNA exit might thus take place through any of
the enlarged
β
-cylinders in HRV2, but in HRV3 and HRV14 only one of the
