Disulfide bond formation in NGR fiber-modified adenovirus is essential for retargeting to aminopeptidase N.
The peptide motif NGR (asparagine-glycine-arginine) is known to bind to aminopeptidase N (APN). We have constructed five adenoviruses (Ads) bearing NGR in the HI loop of the adenoviral fiber protein. We compared the targeting properties of the NGR peptide within different amino acid environments and showed that their cellular receptor(s) were not identical. Ads containing NGR within potentially cyclic sequences flanked by cysteines retargeted viruses mainly to APN, while Ads containing NGR within linear sequences not containing cysteines retargeted Ads mainly to alpha(v)beta(3) integrin, albeit with a lower affinity. Finally, we show evidence that disulfide bond formation within an Ad bearing the CDCNGRCFC sequence is essential for retargeting to APN, suggesting that this sequence does indeed assume a cyclic structure which facilitates NGR binding to APN. Therefore, our study underscores the importance of cysteine residues flanking targeting peptides for not only affinity but also specificity of the retargeted Ad.
Majhen
Dragomira
D
Laboratory for Genotoxic Agents, Division of Molecular Biology, Ruer Bosković Institute, Bijenicka 54, 10000 Zagreb, Croatia.
Gabrilovac
Jelka
J
Eloit
Marc
M
Richardson
Jennifer
J
Ambriović-Ristov
Andreja
A
D000256:Adenoviridae / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D018826:CD13 Antigens / Q000378:metabolism*; D036022:Capsid Proteins / Q000235:genetics* / Q000378:metabolism*; D002460:Cell Line; D003545:Cysteine; D004220:Disulfides; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D013379:Substrate Specificity; D014161:Transduction, Genetic
D036022:Capsid Proteins; D004220:Disulfides; D039302:Integrin alphaVbeta3; C018315:hexon capsid protein, Adenovirus; D018826:CD13 Antigens; D003545:Cysteine