Birnaviridae

Birnavirus VP2 protein
crystal structure of infectious bursal disease virus vp2 subviral particle
Identifiers
Symbol	Birna_VP2
Pfam	PF01766
Pfam clan	CL0055
InterPro	IPR002662
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Birnaviridae is a family of viruses. Salmonid fish, young sexually immature chickens, and insects serve as natural hosts. There are currently six species in this family, divided among 4 genera. Diseases associated with this family include: IPNV: infectious pancreatic necrosis in salmonid fish, causes significant losses to the aquaculture industry. chronic infection in adult, and acute viral disease in young salmonid fish.

The Birnaviridae genome encodes several proteins:

Birnaviridae RNA-directed RNA polymerase (VP1), which lacks the highly conserved Gly-Asp-Asp (GDD) sequence, a component of the proposed catalytic site of this enzyme family that exists in the conserved motif VI of the palm domain of other RNA-directed RNA polymerases.

The large RNA segment, segment A, of birnaviruses codes for a polyprotein (N-VP2-VP4-VP3-C) that is processed into the major structural proteins of the virion: VP2, VP3 (a minor structural component of the virus), and into the putative protease VP4. VP4 protein is involved in generating VP2 and VP3.recombinant VP3 is more immunogenic than recombinant VP2.

Infectious pancreatic necrosis virus (IPNV), a birnavirus, is an important pathogen in fish farms. Analyses of viral proteins showed that VP2 is the major structural and immunogenic polypeptide of the virus. All neutralizing monoclonal antibodies are specific to VP2 and bind to continuous or discontinuous epitopes. The variable domain of VP2 and the 20 adjacent amino acids of the conserved C-terminal are probably the most important in inducing an immune response for the protection of animals.