Viruses penton

The structure of the capsid (protein shell) for an icosahedral virus such as tomato bushy stunt virus. Pentons (P) are located at the 12 vertices of the icosahedron. Hexons (H), of which there are 20, form the edges and faces of the icosahedron. Each penton is composed of five protein subunits and each hexon is composed of six protein subunits. In all, the structure contains 180 protein subunits. 

An icosahedral virus particle composed of 252 capsomeres 240 being hexons and 12 being pentons... 

Adenovirus Features. Adenovirus is a nonintegrating double-stranded DNA virus that is packaged into an icosahedra structure consisting of seven different proteins. The vertices of the icosahedrons contain a penton base with a protruding... 

Because eicosahedra are regular geometric solids and the faces can be made up of hexons and pentons of identical subunits, it might seem that self-assembly of eicosahedral viruses would occur easily. However, the subunits usually must be able to assume three or more different conformations and the shells can easily be assembled incorrectly. Several stategies are em-... 

Larger icosahedral viruses that have been structurally well characterized do not obey the simple quasi-equivalence rule. For example, adenovirus capsids, for which T = 25, are built of 240 hexons (six-coordinated units) that are trimers of the major structural protein, and the 12 pentons consist of a different protein (Burnett 1984). Polyomavirus capsids, for which T = 7, are built of a single major structural protein,... 

Fig. 4. Adenovirus and bacteriophage PRDl. Top On the left, a density isosurface representation of adenovirus at 25-A resolution is shown. The 5-fold axis, occupied by the protein penton, is marked with a pentagon. A trimer of hexon is marked with a triangle close by arrays of hexon extend outward in all directions from the pentagonal vertex, forming the flat faces of the virus. On the right, a close-up of the 5-fold axis is shown (top) and below that a close-up of the hexon trimer with it crystal structure fitted (Athappilly et at, 1994 Stewart et al, 1991). Bottom The Susl mutant of PRDl is shown...

To better augment the structural differences between the hexons and pentons that are being discerned by VP5, the virus was decorated with the antibody 6F10 [110]. The residues being recognized by this antibody were... 

The image reconstruction of the Fab—virus complex clearly shows that the Fab is binding to a flexible portion of the penton base. Antibody binding to the penton base did not result in any observable structural change in the virion. Rather than appearing as a well-defined bUobed structure as observed in other Fab—virus complexes, these bound Fab fragments formed a ring of density above the penton base. This is similar to what was observed in the 4C4—FMDV reconstruction, in which the 4C4... 

Wingfield, P. T., Stahl, S.J., Thomsen, D. R., Homa, F. L., Booy, F. P., Trus, B. L., and Steven, A. C. (1997). Hexon-only binding of VP26 reflects differences between the hexon and penton conformations fo VP5, the major capsid protein of herpes simplex virus./ Virol. 71, 8955-8961. 

K. L., Baker, T. S., and Smith, T. J. (2002). An antibody to the putative aphid recognition site on cucumber mosaic virus recognizes pentons but not hexons. /. Virol. 76, 12250-12258. 

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