Incorporation of (R)- and (S)-3',4'-seco-thymidine into oligodeoxynucleotides: hybridization properties and enzymatic stability.

Novel flexible oligodeoxynucleotide analogues containing (R)- and (S)-3',4'-seco-thymidine were synthesized on an automated DNA-synthesizer using the phosphoramidite approach. Oligodeoxynucleotide analogues (17-mers) having one or three modifications in the middle or one or two modifications in the ends were evaluated with respect to hybridization properties and enzymatic stability. 3'-End-modified oligomers were stable towards 3'-exonuclease degradation and displayed acceptable hybridization properties.