Alternate dab-aegPNAs: synthesis, nucleic acid binding studies and biological activity

As part of our research on new oligonucleotide analogs for therapeutic and diagnostic use, here we explored the ability of an alternate dab-aegPNA oligomer to bind complementary natural nucleic acids. The alternate homothymine dab-aegPNA, synthesized following a chirally safe procedure and fully characterized by ESIMS and CD, was capable of forming hybrids with complementary DNA and RNA with enhanced thermal stability in comparison to natural oligomers, as shown by CD and UV spectroscopies. The stoichiometry of the complexes formed was determined by CD titration experiments that suggested triple helices formation. With respect to an analogous t12 strand composed entirely of aegPNA, the chiral alternate t12 oligomer presented an enhanced solubility in aqueous medium and did not form aggregates. Human serum stability assays performed on the new alternate oligomer evidenced a noteworthy enzymatic resistance. Moreover, the efficiency of dab-aegPNA in interfering with the reverse transcription of eukaryotic mRNA, and the absence of cytotoxic effects of the new analog were demonstrated, encouraging us to further study this chiral PNA analog in view of its possible in vivo/in vitro biotechnological applications.