Homologous Superfamily

Group II dsDNA virus coat/capsid protein (IPR016112)

Short name: VP_dsDNA_II

Description

Hexon is a major coat protein found in various species-specific Adenoviruses, which are type II dsDNA viruses. Hexon coat proteins are synthesised during late infection and form homo-trimers. The 240 copies of the hexon trimer that are produced are organised 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 [PMID: 7932702]. The hexon coat protein is a duplication consisting of two domains with a similar fold packed together like the nucleoplasmin subunits. Within a hexon trimer, the domains are arranged around a pseudo 6-fold axis. The domains have a beta-sandwich structure consisting of 8 strands in two sheets with a jelly-roll topology; each domain is heavily decorated with many insertions [PMID: 12915569].

The major capsid proteins (vp54 and vp72) found in Iridoviruses, Phycodnaviruses, Asfarviruses and Ascoviruses share the same structure. All these viruses are type II dsDNA viruses with no RNA stage. This is the most abundant structural protein and can account for up to 45% of virion protein [PMID: 10082389]. The structure of vp54 has been determined from Paramecium bursaria Chlorella virus 1 (PBCV-1), a very large icosahedral virus containing an internal membrane enclosed within a glycoprotein coat. The vp54 protein is a duplication consisting of two domains with a similar fold packed together like the nucleoplasmin subunits. The vp54 protein forms a trimer, where the domains are arranged around a pseudo 6-fold axis. The domains have a beta-sandwich structure consisting of 8 strands in two sheets with a jelly-roll topology [PMID: 12411581].

Similarly, the major capsid protein p3 from Bacteriophage PRD1 also adopts a similar double-barrel structure comprising two eight-stranded viral beta-barrels or jelly rolls, each of which contains a 12-residue alpha-helix. This protein then trimerises through a 'trimerisation loop' sequence, and is incorporated within the viral capsid [PMID: 11752778].

This entry represents a structural domain consisting of a beta-sandwich structure containing 8 strands in two sheets with a jelly-roll topology. This domain is found several type II dsDNA viruses, including Adenoviruses, Iridoviruses, Phycodnaviruses, Asfarviruses, Ascoviruses, and Bacteriophage PRD1.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

No terms assigned in this category.

Cellular Component

GO:0019028 viral capsid

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
SUPERFAMILY