Conformational and chiral selection of oligonucleotides

In view of a better understanding of chiral selection of oligonucleotides, we have studied the hybridization of D- and L-CNA (cyclohexane nucleic acids) and D- and t.-DNA, with chiral D-beta-homoDNA and achiral PNA (peptide nucleic acids). PNA hybridizes as well with D-DNA, L-DNA as with D-beta-homo-DNA. The structure of the PNA D-beta-homo-DNA complex is different from the PNA . DNA duplexes. D-CNA prefers D-DNA as hybridization partner, While L-CNA prefers D-beta-homo-DNA as hybridization partner. ne conformation of the enantiomeric oligonucleotides D-CNA and L-CNA in the supramolecular complex with D-DNA and D-beta-homo-DNA, respectively, is different. These data may contribute to the confirmation of a hypothesis of the existence of achiral informative polymers as RNA predecessor, and to the understanding of homochirality of nucleic acids.