Borane phosphonate DNA: a versatile unnatural internucleotide linkage

Abstract

Borane phosphonate (bp) is a new class of unnatural internucleotide linkages where one of the oxygens in the phosphodiester linkage is replaced by an electron deficient borane (BH₃) group. These unnatural internucleotide linkages are resistant to nuclease, RNase H active and hydrophobic, which significantly enhance the cellular uptake. The bp-linked oligo can be synthesized both enzymatically and chemically. Like borane (BH₃) and diborane (B₂H₆) reagents, the borane group (BH₃) in borane phosphonate oligo retains its reactivity towards a specific substrate. BpDNA reduces metal ions, such as Au(III), Ag(I), and Pt(II), and produces the corresponding metal nanoparticles; this enables the DNA-mediated morphology control and spatial positioning of nanoparticles and DNA nanostructures. Moreover, the bp-diesters undergo oxidative substitution with various nucleophiles, such as amines, alcohols, thiols, etc., upon activation by iodine; this leads to a route for post-synthetic modification of DNA including DNA functionalization. This article discusses some of the recent studies reported on bp-oligo synthesis and its applications.