icosahedral viral capsid T=pseudo3 icosahedral viral capsid 2012-07-18T02:10:02Z VZ:809 GO:0039618 T=pseudo3 capsids are not T=3 symmetry as described by Caspar and Klug (PMID:14019094) because the basic unit is composed of three different proteins. Since the three subunits are morphologically very similar, the structure is therefore a pseudo T=3. cellular_component bf The protein coat that surrounds the infective nucleic acid in some virus particles where the subunits (capsomeres) are arranged to form an icosahedron with pseudo T=3 symmetry. The T=pseudo3 capsid is composed of 12 pentameric and 20 hexameric capsomeres.