Hybridization of antisense oligonucleotides with the 3 ' part of tRNA(Phe)

The interaction of antisense oligodeoxyribonucleotides with yeast tRNA(Phe) was investigated. 14-15-mers complementary to the 3'-terminal sequence inc luding the ACCA end bind to the tRNA under physiological conditions, At low oligonucleotide concentrations the binding occurs at the unique complement ary site. At higher oligonucleotide concentrations, the second oligonucleot ide molecule binds to the complex due to non-perfect duplex formation in th e T-loop stabilized by stacking between the two bound oligonucleotides. In these complexes the acceptor stem is open and the 5'-terminal sequence of t he tRNA is accessible for binding of a complementary oligonucleotide, The r esults prove that the efficient binding of oligonucleotides to the 3'-termi nal sequence of the tRNA occurs through initial binding to the single-stran ded sequence ACCA followed by invasion in the acceptor stem and strand disp lacement. (C) 1999 Federation of European Biochemical Societies.