Adenovirus penton-base proteins

The adenovirus fiber protein is trimeric, and the monomer varies in length from 320 to 587 residues (Chroboczek et al, 1995). The N-terminal region of the fiber protein associates with the penton base protein in the... 

To localize the RGD residues on the Ad penton base, a cryo-EM reconstruction was performed of adenovirus type 2 (Ad2) complexed with an RGD-specific Eab fragment from an mAb directed against the penton base (Stewart et al, 1997). This structural analysis revealed that the RGD regions are at the top of protrusions on the pentameric penton base protein. In addition, it was deduced from the diffuse nature of the Fab density that the RGD residues were in a structurally variable surface loop. Comparison of the knovra sequences of the penton base protein from various adenovirus serotypes suggested that type 12 adenovirus (Adl2) would have the least structurally variable RGD loop, as Ad 12 has 45 fewer residues in the variable region flanking the conserved RGD residues than are found in Ad2 (Chiu et al, 1999). 

Adenoviruses consist of a large double-stranded DNA genome (about 36 kilobase pairs long) packaged within a nonenveloped icosahedral capsid that is primarily composed of three virus-encoded proteins (hexon, pen ton base, and fiber proteins) [39]. The fiber proteins protrude fi om the surface of the virus and mediate its attachment to target cells via a high affinity interaction with the cellular receptor CAR (coxsackievirus and adenovirus receptor) [40]. The virus is then internahzed into endosomal vesicles via specific interactions between the penton base proteins and ofy integrins [41]. Adenoviruses escape these vesicles by an acid-induced endosomolytic activity and are transported to the nucleus, into which they enter via pores in the nuclear membrane [42]. 

Seth P. Adenovirus-dependent release of choline from plasma membrane vesicles at an aeidic pH is mediated by the penton base protein. J Virol 1994 68 1204-1206. 

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... 

The adenovirus capsid is an icosahedral capsid that can be described as pseudo-T=25. The 12 pentameric vertices are each composed of 5 molecules of the penton bases, carrying a trimeric fiber. The 20 faces are composed of the 4 molecules of hexon protein, which itself is a trimer of the 967-residue-long polypeptide II. The crystal structure of the hexon has been solved and it reveals that the trimeric subunits are intimately intertwined, thus accounting for their observed stability. The capsid also... 

The primary cellular attachment receptor for adenovirus has not yet been identified, but the vitronectin-binding integrins Oy/Sj and Oy/ s have been shown to be coreceptors for viral internalization [113] and interact with the penton base of the capsid. It is thought that the initial interaction with the cell surface is mediated by the protruding fiber proteins. The various subgroups presumably bind to different receptors because they do not compete with one another for cellular binding. Subsequent interactions between the Oy coreceptors and the penton base... 

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