The capsid is composed 60 asymmetric units made of 2 protein (T=2*), for a total of 120 capsid proteins.

The T=2* symmetry is an nonofficial appellation, to be rigorous the capsid has a T=1 symmetry with each unit composed of a homodimer.

Icosahedric triangulation number is calculated following Caspar and Klug system

**Physical principles in the construction of regular viruses**

D. L. Caspar, A. Klug

Cold Spring Harb. Symp. Quant. Biol. 1962; 27: 1?24