[Oligodeoxynucleotides, containing 6-O-alkylated guanine segments recognized by HaeIII restriction endonuclease]

A series of self-complementary decadeoxynucleotides containing a native or modified HaeIII site GGCC (with one or both guanine residues 6-O-cetylated) have been synthesized by the phosphotriester approach. The nonmodified decanucleotide is normally digested with snake venom phosphodiesterase as well as with HaeIII and BspI restriction endonucleases, whereas the bulky 6-O-alkyl substituent strongly inhibits the VPDE hydrolysis and completely prevents digestion with the endonucleases.