Capsid structure

Arnold, E., et al. Implications of the picornavirus capsid structure for polyprotein processing. Proc. Natl. Acad. ScL USA. 84 21-25, 1987. 

Rayment, I., et al. Polyoma virus capsid structure at 22.5 A resolution. Nature 29S 110-115, 1982. 

Polyoma- and papillomaviruses share a common capsid structure that is assembled from 72 pentameric capsomeres arranged on a T = 7 icosahedral lattice. Assembly studies of polyomaviruses were first initiated by expression of the major capsid protein of mouse polyomavirus, VPl, in... 

VII. The Mature Capsid Structure Filled and Empty Shells. 310... 

Combining these two approaches, by determining the crystal structure of individual subcomponents and fitting these into the lower resolution maps of intact particles, may offer the best current hope for obtaining high-resolution information about virion structure. An example of this is provided by adenovirus, where the crystal structure of the hexon, formed by three copies of the 100-kDa major structural protein, has been fitted into a low-resolution capsid structure determined by electron cryomicro-scopy to provide a clearer picture of capsid organization and information about the locations of minor capsid proteins (Stewart et al, 1993). A similar strategy has been used to fit the crystal structure of a portion of the HSV-1 major capsid protein (VPS) into an intermediate-resolution map of the capsid (B. Bowman, personal communication). 

Fig. 5. Comparison of HSV-1 procapsid and capsid structures. Outside (A and B) and inside (C and D) views of reconstructions of the HSV-1 procapsid (A and C) and capsid (B and D). All views are shovm looking along a 3-fold icosahedral axis. Although it retains the same icosahedral symmetry, as shovm by the hexagonal arrangement of the capsomers apparent in the internal view (C), the procapsid subunits are much less clearly defined than those in the capsid. In addition, the contacts between individual subunits are much more tenuous and the continuous floor, formed by extensions from the bases of the capsomers, is not present. Note also the contrast in shape between the spherical procapsid and the polyhedral capsid. Scale bar 500 A. [Image supplied by Benes Trus.]...

In the first studies, antibodies were used to elucidate the dynamic nature of poliovirus [51]. Antibodies were raised against peptides representing VP4 and the N termini of VPl. In the crystal structures of all of the picornaviruses, these termini lie at the capsid-RNA interface and are therefore not exposed to external solvent [27, 46, 52-55]. These antibodies bound to the virus when the particles were heated to 37°C but did not bind when added to virus at room temperature or when the virus was heated to 37°G and then cooled to room temperature. Therefore, although difficult to visualize with the static structure of the capsid, the only explanation for these results is that these buried termini are transiently exposed. This exposure is facilitated by higher temperatures and was proposed to be part of the normal infection process. This idea of dynamic capsid structures was subsequently supported by mass spectroscopy analysis of flock house virus [56] and rhinovirus [57] and by a series of drug—poliovirus structures [58]. 

A comparative study of different poliovirus capsid structures revealed a hydrophobic pocket that contained sites for cellular lipid interaction (Hogle et al, 1985 Filman et al, 1989). This lipid component, which is termed the pocket factor, may be sphingosine. Amino acids that modulate temperature sensitivity of poliovirus infectivity map to the interfaces between capsid protomers and are adjacent to the site of lipid binding. A similar lipid molecule appears to be present in some but not all... 

Mature capsid structure, of bacteriophage T7 procapsid assembly, 310—315 Membrane-containing isometric viruses, structures of, 60-63 Membrane fusion models, of influenza hemagglutinin (HA), 340-343... 

Procapsid/capsid structure, with herpes simplex virus 1 (HSV-1), 398 projectBjFile, 111, 112 Prokaryotic expression systems, 4-8 Escherichia coli and, 4—8 Protein folding, of influenza hemagglutinin (HA), 351-352... 

Chapman and Liljas, Fig. 1. The canonical jelly-roll fi barrel seen in many capsid structures, as exemplified by (a) satellite Panicum panicum mosaic virus (Ban and McPherson, 1995), (b) poliovirus VPS (Filman et al, 1989), (c) canine parvovirus (Filman et al., 1989), and (d) Nudaurelia capensis ui virus (Munshi et al, 1996). The view is approximately tangential to the capsid surface. As in many of the figures, the eight strands of the jelly roll are highlighted by darker colors from blue (/IB) to red (/II) The visible N termini and C termini are marked with Nt and Ct, respectively, and the loops connecting the strands are denoted BC, CD, etc. All the ribbon drawings have been made with the program Molscript (Kraulis, 1991). 

Viral capsid structures are built with high efficiency and economy from a single fundamental unit and as such are analogous to geodesic domes. There are five regular polyhedra, a tetrahedron, a cube, an octahedron, a dodecahedron and an icosaliedron. These polyhedra are often referred to as Platonic solids because of their significance in Plato s natural... 

Donald L. D. Caspar showed that a particular virus, tomato bushy stunt virus (TBSV), has a capsid structure with icosahedral symmetry. 

All viruses contain (glyco)protein materials on their surface, whether as an integral part of the capsid structure or in the form of spikes embedded in... 

Keywords AAV capsid Proteolysis capsid structure Serotype Vector production Colnmn chromatography Gene therapy... 

Xie Q, Chapman MS. Canine parvovirus capsid structure, analyzed at 2.9 A resolution. J Mol... 

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