C Terminus of Infectious Bursal Disease Virus Major Capsid Protein VP2 Is Involved in Definition of the T Number for Capsid Assembly
AUTOR(ES)
Castón, José R.
FONTE
American Society for Microbiology
RESUMO
Infectious bursal disease virus (IBDV), a member of the Birnaviridae family, is a double-stranded RNA virus. The IBDV capsid is formed by two major structural proteins, VP2 and VP3, which assemble to form a T=13 markedly nonspherical capsid. During viral infection, VP2 is initially synthesized as a precursor, called VPX, whose C end is proteolytically processed to the mature form during capsid assembly. We have computed three-dimensional maps of IBDV capsid and virus-like particles built up by VP2 alone by using electron cryomicroscopy and image-processing techniques. The IBDV single-shelled capsid is characterized by the presence of 260 protruding trimers on the outer surface. Five classes of trimers can be distinguished according to their different local environments. When VP2 is expressed alone in insect cells, dodecahedral particles form spontaneously; these may be assembled into larger, fragile icosahedral capsids built up by 12 dodecahedral capsids. Each dodecahedral capsid is an empty T=1 shell composed of 20 trimeric clusters of VP2. Structural comparison between IBDV capsids and capsids consisting of VP2 alone allowed the determination of the major capsid protein locations and the interactions between them. Whereas VP2 forms the outer protruding trimers, VP3 is found as trimers on the inner surface and may be responsible for stabilizing functions. Since elimination of the C-terminal region of VPX is correlated with the assembly of T=1 capsids, this domain might be involved (either alone or in cooperation with VP3) in the induction of different conformations of VP2 during capsid morphogenesis.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=114663Documentos Relacionados
- Canarypox virus expressing infectious bursal disease VP2 protein as immunogen for chickens
- The major antigenic protein of infectious bursal disease virus, VP2, is an apoptotic inducer.
- The Last C-Terminal Residue of VP3, Glutamic Acid 257, Controls Capsid Assembly of Infectious Bursal Disease Virus
- The Oligomerization Domain of VP3, the Scaffolding Protein of Infectious Bursal Disease Virus, Plays a Critical Role in Capsid Assembly
- A Recombinant Newcastle Disease Virus (NDV) Expressing VP2 Protein of Infectious Bursal Disease Virus (IBDV) Protects against NDV and IBDV