D-Altritol nucleic acids (ANA): Hybridisation properties, stability, and initial structural analysis

Oligonucleotides composed of a phosphorylated D-altritol backbone with nucl eobases introduced in the 2'-position, hybridise strongly and sequence-sele ctively with RNA in an antiparallel way. The order of hybridisation strengt h is: dsANA > ANA:RNA > ANA:DNA. Complexes between ANA and RNA dr DNA are m ore stable than between HNA and natural oligonucleotides. The dsANA hybrid is extremely stable. When compared with an identical dsDNA sequence, the De lta T-m per modification is +10.2 degrees C for a hexamer. CD spectral anal ysis indicates that ANA complexes are very similar to the A-form dsRNA dupl ex. ANA are stable in alkaline medium up to pH 12 and, likewise, are not de graded in human serum.