Capsid, viral

Rossmann, M.G. Antiviral agents targeted to interact with viral capsid proteins and a possible application to human immunodeficiency virus. Proc. Natl. Acad. Sci. USA, 85 4625-4627, 1988. 

A capsid is a proteinaceous shell encasing the viral genome. Viral capsids are polymeric, ordered structures composed of one or more virus encoded subunits. 

I. Ali, D. Marenduzzo, and J. M. Yeomans, Polymer packaging and ejection in viral capsids ... 

Esterling, B.A. et al., Defensiveness, trait anxiety, and Epstein-Barr viral capsid antigen antibody titers in healthy college students, Health Psychol., 12, 132, 1993. 

Merckel, M. C., Huiskonen, J. T., Bamford, D. H., Goldman, A., and Tuma, R. (2005). The structure of the bacteriophage PRD1 spike sheds light on the evolution of viral capsid architecture. Mol. Cell 18, 161-170. 

Vainshtein, B. K. (1966). Diffraction of X-Rays by Chain Molecules. Elsevier, Amsterdam. Valery, C., Patemostre, M., Robert, B., Gulik-Krzywicki, T., Narayanan, T., Dedieu, J. C., Keller, G., Torres, M. L., Cherif-Cheikh, R., Calvo, P., and Artzner, F. (2003). Biomimetic organization Octapeptide self-assembly into nanotubes of viral capsid-like dimension. Proc. Natl. Acad. Sci. USA 100, 10258-10262. 

Bertling WM, Gareis M, Paspaleeva V, Zimmer A, Kreuter J, Numberg E, Harrer P (1991) Use of liposomes, viral capsids, and nanoparticles as DNA carriers. Biotechnol Appl Biochem 13 390 405. 

In a paper describing the structure of regular viruses, Caspar and Klug [4] have shown that viral capsids use self-assembly to construct spherical shells up to a hundred nanometers in diameter by utilizing identical copies of proteins as chemical... 

About 1.5-2 hours after infection the first viral structural proteins can be detected in cells efficiently infected by SFV (see Kaariainen and S6-derlund, 1978). By 3-4 hours the synthesis of host cell proteins is shut off. The mechanism of host protein shutoff is not yet known, but studies by van Steeg (1982) suggest that it is the viral capsid protein itself which is responsible for the selective inhibition of host protein synthesis. The capsid protein seems to reduce the activity of the initiation factors elF-4B and CAP binding protein below levels necessary for the formation of the 80 S initiation complex from host mRNA. Translation of the viral 26 S RNA is, however, unaffected. More studies are clearly needed to substantiate this interesting possibility. 

Studies of the alphavirus life cycle have revealed how heavily the virus relies on cellular processes for replication. The paucity of functions that seem unique to the virus is striking. The binding of the virus to the cell surface and the fusion of its membrane intracellularly depend on the viral spike glycoproteins. RNA-dependent RNA polymerases specific for the virus catalyze the replication of the viral RNA. Exit from the cell requires the interaction of the viral spike proteins with the viral capsid... 

HRVs are non-enveloped viruses of icosahedral overall shape [44]. Located on the exterior of the viral capsid are three structural proteins (VPl, VP2 and VP3), each consisting of an eight-stranded antiparallel -barrel. VP4 is found at the interface with the RNA inside the virus. A pocket factor is usually bound to a hydrophobic canyon binding site within the VPl -barrel. This lipid-like molecule is important for the stability of the capsid and has been... 

The refined coordinates will correspond to either the icosahedral asymmetric unit or the crystallographic asymmetric unit, hence symmetry operations must be applied to generate the whole capsid. A useful repository of virus structure information is the website http // viperdb.scripps.edu/ where portions of the viral capsid can be generated. 

Tipranavir, a VIH-PR inhibitor, was launched for AIDS therapy (Figure 8.12). Pleconaril inhibits adhesion by binding the viral capsid. It is currently being evaluated for viral infections of the respiratory tract, in particular, for picornavims (meningitis) and rhinovirus (colds) (Figure 8.12). 

The benzimidazole riboside maribavir is under active clinical investigation as an anti-CMV agent. Unlike currently available agents that inhibit CMV DNA polymerase, this agent inhibits viral DNA assembly as well as egress of the viral capsid from the nucleus of infected cells. 

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