T=21 icosahedral capsid


image

The capsid is composed 60 asymmetric units made of 21 proteins (T=21), for a total of 1260 capsid proteins. These capsids are skewed, and are therefore described as either right- (dextro) or left- (laevo) handed.



image

Icosahedric triangulation number is calculated following Caspar and Klug system


Corticoviridae capsid symmetry is a pseudo T=21 structure, because hexamers are formed by 3 subunits instead of 6.

image