HYBRIDIZATION PROPERTIES OF OLIGOARABINONUCLEOTIDES

3'-Phosphoramidite derivatives of arabinocytidine, arabinoadenosine, a nd arabinouridine were prepared and used for the solid-phase synthesis of oligoarabinonucleotides (arabinonucleic acid, or ANA). Thermal den aturation analysis and gel mobility shift assays were used to investig ate the interaction between ANA and complementary DNA and RNA. In gene ral, the ANA/ DNA and ANA/RNA complexes exhibited melting temperatures comparable to those of the corresponding DNA/DNA and DNA/RNA complexe s. Thus the inversion of stereochemistry at the C2' of ribonucleotides does not have a negative effect on interaction with natural sequences . In fact, in complexes with poly dT, oligoarabinoadenylates displayed greater hybridization affinity than oligoriboadenylates. In summary, we observed that (i) ara(Ap)(7)A interacted favourably with poly rU an d poly dT; (ii) ara(Cp)(7)C formed a stable complex with poly rG; (iii ) ara(Up)(7)U did not bind with complementary poly rA; and (iv) the mi xed oligoarabinonucleotide ara(UCU UCC CUC UCC C) formed complexes wit h complementary DNA and RNA. Hybridization was observed between the ph osphorothioatelinked arabinoadenylate ara(Aps)(7)A and poly rU and pol y dT; however, this binding was weaker than that between the phosphoro thioate-linked deoxyriboadenylate d(Aps)(7)A and poly rU and poly dT. Both ara(Aps)(7)A and its deoxy analog d(Aps)(7)A displayed significan t and similar resistance to digestion by snake venom phosphodiesterase .