Hexon, adenovirus major coat protein, N-terminal domain
Hexon is the major coat protein from adenovirus type 2. Hexon forms a homo-trimer. The 240 copies of the hexon trimer are organized so that 12 lie on each of the 20 facets. The central 9 hexons in a facet are cemented together by 12 copies of polypeptide IX. The penton complex, formed by the peripentonal hexons and base hexon (holding in place a fibre), lie at each of the 12 vertices. The N and C-terminal domains adopt the same PNGase F-like fold although they are significantly different in length.