PubReading [239] - Triplex-forming properties and enzymatic incorporation of a base-modified nucleotide capable of duplex DNA recognition at neutral pH - D. Rusling

<p>The sequence-specific recognition of duplex <strong>DNA</strong> by unmodified parallel<strong> triplex</strong>-forming oligonucleotides is restricted to low pH conditions due to a necessity for <strong>cytosine protonation</strong> in the third strand. This has severely restricted their use as gene-targeting agents, as well as for the detection and/or functionalisation of synthetic or genomic DNA. Here I report that the nucleobase 6-amino-5-nitropyridin- 2-one (Z) finally overcomes this constraint by acting as an uncharged mimic of protonated cytosine. Synthetic <strong>TFO</strong>s containing the nucleobase enabled stable and selective triplex formation at oligopurine- oligopyrimidine sequences containing multiple isolated or contiguous GC base pairs at neutral pH and above. Moreover, I demonstrate a universal strategy for the enzymatic assembly of Z-containing TFOs using its commercially available deoxyribonucleotide triphosphate. These findings seek to improve not only the recognition properties of TFOs but also the cost and/or expertise associated with their chemical syntheses.</p><p><a href="https://doi.org/10.1093/nar/gkab572"><em>https://doi.org/10.1093/nar/gkab572</em></a><em> - 2021</em></p>