Bulliard, YannickNarvaiza, IñigoBertero, AlessandroPeddi, ShyamRöhrig, Ute F.Ortiz, MillánZoete, VincentCastro-Díaz, NatalyTurelli, PriscillaTelenti, AmalioMichielin, OlivierWeitzman, Matthew D.Trono, Didier2010-12-062010-12-062010-12-06201010.1128/JVI.01651-10https://infoscience.epfl.ch/handle/20.500.14299/61925WOS:000286420900033Members of the human APOBEC3 family of editing enzymes can inhibit various mobile genetic elements. APOBEC3A (A3A) can block the retrotransposon LINE-1 and the parvovirus adeno-associated virus type 2 (AAV-2) but does not inhibit retroviruses. In contrast, APOBEC3G (A3G) can block retroviruses but has only limited effects on AAV-2 or LINE-1. What dictates this differential target specificity remains largely undefined. Here, we modeled the structure of A3A based on its homology with the C-terminal domain of A3G, and further compared the sequences of human A3A with that of 11 non-human primate orthologues. We then used these data to perform a mutational analysis of A3A, examining its ability to restrict LINE-1, AAV-2 and foreign plasmid DNA, and to edit a single-stranded DNA substrate. The results revealed an essential functional role for the predicted single-stranded DNA-docking groove located around the A3A catalytic site. Within this region, amino acid differences between A3A and A3G are predicted to affect the shape of the polynucleotide-binding groove. Correspondingly, transferring some of these A3A-residues to A3G endows the latter protein with the ability to block LINE-1 and AAV-2. These results suggest that the target-specificity of APOBEC3 family members is partly defined by structural features influencing their interaction with polynucleotide substrates.Hiv-1 Reverse TranscriptionDna Deaminase DomainCrystal-StructureCatalytic DomainLine-1 RetrotranspositionAdenoassociated VirusCytidine DeaminaseMammalian-Cells7Sl RnaProteinstext::journal::journal article::research article