without changing your settings we'll assume you are happy to receive all RSC cookies.
You can change your cookie settings by navigating to our Privacy and Cookies page and following the instructions. These instructions
are also obtainable from the privacy link at the bottom of any RSC page.
The capacity of three different purine bases, viz. 2,6-bis(3,5-dimethylpyrazol-1-yl)purine, 2-(3,5-dimethylpyrazol-1-yl)adenine and 2,6-bis(2-acetyl-1-methylhydrazino)purine, to form metal-ion mediated base pairs with the native nucleobases has been examined. For this purpose, ribonucleosides derived from these bases were incorporated into an intrastrand or a 3′-terminal position of short 2′-O-methyl oligoribonucleotides and the hybridization properties of these base modified oligomers in the absence and presence of three different metal ions (Cu2+, Zn2+ and Pd2+) were studied by UV- and CD-spectrometry. The first two bases were found to stabilize short oligonucleotide duplexes when incorporated into the 3′-termini of both strands, even in the absence of divalent metal ions but especially in the presence of Cu2+. The highest melting temperature determined for such a duplex was 71.8 °C, nearly 30 °C higher than the Tm of the respective solely Watson–Crick paired duplex. Despite the dramatic stabilizing effect of the terminal metallo-base pairs, these short modified oligonucleotides retained sequence-selectivity for the internal Watson–Crick base pairs: two internal mismatches dropped the melting temperature to 10–11 °C. In an internal position, only 2,6-bis(3,5-dimethylpyrazol-1-yl)purine, which in the absence of metal ions was destabilizing, exhibited metal-ion-dependent stabilization of duplex formation with unmodified 2′-O-methyl oligoribonucleotides. The melting temperature in the presence of Cu2+ was increased from 6 to 14 °C, depending on the identity of the opposite base.
Fetching data from CrossRef. This may take some time to load.
Organic & Biomolecular Chemistry
- Information Point