Ad3 penton base mutations that prevent the formation of PtDd.

A) Localization of D100 (in red) and R425 (in blue) in the Ad3 dodecahedron context (PDB accession 4AQQ). The panel shows a representative view of contacts taking place at the interface between adjacent pentamers in a slab view. B) Two out the five monomers constitutive of a penton base are coloured in blue and green with D100 and R425 highlighted. The salt bridge between these monomers is shown. C) Amino acids sequence of Ad3 penton base. Substitutions of 58-SELS-61→58-SDVA-61, 100-D→R and 425-R→E were introduced into wild-type Ad3 penton base. The mutated residues are shown in red letters. D) Ad3 vectors. Both vectors contain the same GFP expression cassette inserted into the E3 region of Ad3 in front of the fiber sequence. Both vectors contain the complete E1 regions and are therefore replication-competent. mu-Ad3GFP contains both 100-D→R and 425-R→E mutations in the penton base.