Nucleosides and nucleotides. 171. Thermal and nuclease stabilities of G-quadruplexes consisting of oligodeoxynucleotides containing 5-[N-[2-[N,N-bis(2-amino-ethyl)amino]ethyl]carbamoyl]-2′-deoxyuridine or 5-[N-[3-[N,N-bis(3-aminopropyl)amino]propyl]carbam

The thermal and nuclease stabilities of G-quadruplexes consisting of oligodeoxynucleotides (ODNs) containing 5-[N-[2-[N,N-bis(2-aminoethyl)amino]ethyl]carbamoyl]-2′-deoxyuridine (BAE) or 5-[N-[3-[N,N-bis(3-aminopropyl)amino]propyl]carbamoyl]-2′-deoxyuridine (BAP) are described. We found that the modified nucleosides, BAE and BAP, stabilize quadruplex formation when positioned at the 3′-end of the ODN. Furthermore, ODNs containing the modified nucleosides were more resistant to nucleolytic hydrolysis by snake venom phosphodiesterase than an unmodified ODN.