ALPHA-BETA CHIMERIC OLIGONUCLEOTIDES FORM A NEW STABLE SNAIL-LIKE STRUCTURE

The structure formed by a chimeric alpha-beta-oligonucleotide containi ng the 3'-end alpha-sequence complementary to the 5'-end beta-sequence is described. Chemical strand cross-linking was used to probe the str ucture of this oligonucleotide. The terminal sequences form a stable p arallel duplex, and the internal sequence of the oligonucleotide forms a circle-like loop. This new molecule is resistant to nucleolytic deg radation and also promotes efficient RNase H-mediated cleavage of a co mplementary ribooligonucleotide. Oligonucleotides with this structure therefore should prove useful in the control of gene expression.