Adenovirus fiber penton

The structural proteins of AAV particles have been dissociated with sodium dodecyl sulfate (SDS) or urea and then separated by polyacrylamide gel electrophoresis (Johnson and Hoggan, 1971 Rose et al., 1971). Three proteins were identified with estimated molecular weights of 62-66000 73-80000 and 87-92000, respectively. The smallest polypeptide represented about 80% of the total protein mass while the other two represented approximately 10% each. There was no correspondence in electrophoretic mobility with adenovirus structural proteins except that there was a partial overlap of the major AAV protein and the adenovirus fiber penton. The three AAV capsid proteins were present in all three human serotypes (AAV I-3) and had similar mobilities with the exception that the major protein species of AAV 2 moved slightly faster than the comparable AAV 1 and 3 species. Very minor... 

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... 

D. A. Einfeld, D. E. Brough, P. W. Roelvink, I. Kovesdi, and T. J. Wickham, Construction of a pseudoreceptor that mediates transduction by adenoviruses expressing a hgand in fiber or penton base, J. Virol. 73 9130 (1999). 

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... 

Figure 10.1-3. Schematic structure of an adenovirus particle. Major capsid (hexon, penton, fiber) and core (pV, pVII, Mu) proteins are shown. Abbreviation ITR—inverted terminal repeat TP—terminal protein. (Adapted from Ref. 27.)...

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]. 

This family contains non-enveloped DNA viruses that bind to their receptors via interactions with the distal knob of the penton fibers attached to the vertices of the icosahedral virions. Human adenoviruses mainly cause respiratory and gastrointestinal infections. Several adenoviruses also infect the eye where the most important disease is epidemic keratoconjunctivitis (EKC), caused primarily by Ad8, Adl9, and Ad37. Ad37 binds preferentially to a2-3-linked sialic acid which is the most frequent type of sialic acid linkage in corneal and conjunctival cells [201]. The crystal structure of the Ad37 knob-sialic acid complex has been elucidated [202]. 

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