LNA (locked nucleic acid) and analogs as triplex-forming oligonucleotides

The triplex-forming abilities of some conformationally restricted nucleotide analogs are disclosed and compared herein. 2'-Amino-LNA monomers proved to be less stabilising to triplexes than LNA monomers when incorporated into a triplex-forming third strand. N2'-functionalisation of 2'-amino-LNA monomers with a glycyl unit induced the formation of exceptionally stable triplexes. Nucleotide analogs containing a C2',C3'-oxymethylene linker (E-type furanose conformation) or a C2',C4'-propylene linker (N-type furanose conformation) had no significant effect on triplex stability proving that conformational restriction per se is insufficient to stabilise triplexes.