Homologous Superfamily

Viral capsid/haemagglutinin protein (IPR008980)

Short name: Capsid_hemagglutn

Overlapping entries


Representatives of this viral protein domain are found in the vp7 capsid protein of Bluetongue virus [PMID: 7816101], and African horsesickness virus [PMID: 8648715], the vp6 capsid protein of Bovine rotavirus [PMID: 11285213], and in the haemagglutinin protein of various influenza viruses [PMID: 11867515, PMID: 9817207].

The vp7 and vp6 capsid proteins each consist of two domains, one a beta sandwich, and the other an alpha helical bundle. The beta sandwich domain described here is structurally very similar in vp6 and vp7, and may be involved in the attachment of the virus to the cell. In influenza A and B viruses, the haemagglutinin membrane glycoprotein serves to recognise the cell surface receptor sialic acid, and this domain forms the head region. In influenza C virus, a single multifunctional glycoprotein, the haemagglutinin-esterase-fusion protein, possesses a haemagglutinin domain, which recognises the cell surface receptor 9-O-acetylsialic acid, and bears strong structural resemblance to the haemagglutinin protein of influenza A and B viruses, as well as to the vp6 and vp7 capsid proteins. In each case, the domain consists of a beta-sandwich, in which the strands making up the sheets exhibit a jellyroll fold. The resultant proteins form trimers.

GO terms

Biological Process

GO:0019064 fusion of virus membrane with host plasma membrane

Molecular Function

GO:0046789 host cell surface receptor binding

Cellular Component

GO:0019031 viral envelope

Contributing signatures

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