Design, synthesis, and polymerase-catalyzed incorporation of click-modified boronic acid-TTP analogues

DNA molecules are known to be important materials in sensing, aptamer selection, nanocomputing, and construction of unique architectures. The incorporation of modified nucleobases affords unique DNA properties for applications in areas that would otherwise be difficult or not possible. Earlier, we demonstrated that the boronic acid moiety can be introduced into DNA through polymerase-catalyzed reactions. In order to study whether such incorporation by polymerase is a general phenomenon, we designed and synthesized four boronic acid-modified thymidine triphosphate (TTP) analogues. The synthesis of certain analogues was through the use of a single dialkyne tether for both the Sonogashira coupling with thymidine and the later Cu-mediated [3+2] cycloaddition for linking the boronic acid moiety. This approach is much more efficient than the previously described method, and paves the way for the preparation of a large number of boronic acid-modified TTPs with a diverse set of structural features. All analogues showed very good stability under polymerase chain reaction (PCR) conditions and were recognized as a substrate by DNA polymerase, and thus incorporated into DNA.