Enantio-DNA does not recognize, in general, complementary DNA and RNA

We have synthesized enantio-DNA fragments, i.e. DNA derived from L-deoxyribose sugar of variable size from 6 to 22 nucleotides, containing all four natural bases. We have studied their hybridization toward complementary DNA as well as RNA (in both parallel and antiparallel orientation) by UV and CD analysis and by mobility shift assays on native PAGE. despite previous suggestions based on observed complex formation between homopurine and homopyrimidine strands of opposite chirality, our data show that with common sequences no hybridization is possible between an enantio-DNA and its complementary natural DNA or RNA (with the possible exception of some biased sequences). This finding rules out the possibility of using L-DNA's as antisense agents in the antimessanger approach. Studies are in progress to elucidate the behaviour of enantio-RNA.