The alpha-L-ribo-isomers of RNA and LNA (locked nucleic acid).

The phosphoramidite approach has been used for the automated synthesis of alpha-L-LNA, alpha-L-RNA, and oligomers composed of mixtures of alpha-L-LNA, alpha-L-RNA and DNA monomers. Binding studies revealed very efficient recognition of single-stranded DNA and RNA target oligonucleotide strands. alpha-L-LNAs were shown to be significantly stabilized towards 3'-exonucleolytic degradation. Duplexes formed between RNA and alpha-L-LNA induced E. coli RNase H-mediated RNA cleavage, albeit very slow, at high enzyme concentration.