Viruses viral capsids

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. 

In some viruses, the capsid is surrounded by a lipid membrane (envelope), which is derived from the host cell membrane at the site of vims budding. The membrane contains viral envelope glycoproteins as well as host cell membrane proteins. 

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... 

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. 

We have already dealt with some general aspects of biochemical self-assembly in Section 2.10 including the remarkable formation of viral capsids. There are some biochemical examples, however, that translate readily into supramolecular chemical concepts and have been pivotal in defining the field. One such system is the tobacco mosaic virus, a virus that is very harmful to a variety of crops including tobacco, tomato, pepper, cucumbers and species such as ornamental flowers. This system consists of a helical virus particle measuring some 300 X 18 nm (Figure 10.6). A central strand of RNA is sheathed by 2130 identical protein subunits, each of which contains 158 amino acids. What is remarkable about... 

Yang, G. S. et al. (2002). Virus-mediated transduction of murine retina with adeno-associated virus Effects of viral capsid and genome size. J. Virol. 76 (15), 7651-7660. 

Synthesis of viral capsid protein, envelope protein, reverse transcriptase. Assembly of new virus and release by budding... 

Virus-like particles (VLPs) (Noad and Roy 2003) are produced from viral capsid proteins. The capsid proteins self-assemble to form particles that resemble the virus from which the capsid proteins were derived, but lack any... 

Another general role of post-translational cleavage of polypeptide chains in viral systems is the specific processing of structural proteins leading to the assembly of the virus (44,45). In this respect, the semliki-Forest virus may be considered as an interesting model to find out how proteins which have different cellular locations reach their final sites within the cell. A single messenger RNA directs the synthesis of the viral capsid protein and of two membrane proteins. 

Keywords. Virus, Viral, Viral structure, Capsid, Dynamic, Capsid mobility, Whole virus, Intact virus, MALDI, Electrospray, Proteins, Inactivation... 

Fig. 6. The Flock House virus has an icosahedral symmetry with the y-peptide and the C and N termini of the /3-protein lying internally and away from the surface. However, time resolved proteolysis data indicates that the viral capsid is highly mobile and that internal domains are transiently exposed on the surface...

There have been significant developments in the past few years in the area of macromolecular analysis of whole viruses and viral capsids. The first was the... 

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