6-Pyrazolylpurine as an Artificial Nucleobase for Metal-Mediated Base Pairing in DNA Duplexes.

J Léon,Jens Müller,Indranil Sinha

doi:10.3390/ijms17040554

J Léon, Jens Müller + Show 1 more

Open Access

https://doi.org/10.3390/ijms17040554

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Abstract

The artificial nucleobase 6-pyrazol-1-yl-purine (6PP) has been investigated with respect to its usability in metal-mediated base pairing. As was shown by temperature-dependent UV spectroscopy, 6PP may form weakly stabilizing 6PP–Ag(I)–6PP homo base pairs. Interestingly, 6PP can be used to selectively recognize a complementary pyrimidine nucleobase. The addition of Ag(I) to a DNA duplex comprising a central 6PP:C mispair (C = cytosine) leads to a slight destabilization of the duplex. In contrast, a stabilizing 6PP–Ag(I)–T base pair is formed with a complementary thymine (T) residue. It is interesting to note that 6PP is capable of differentiating between the pyrimidine moieties despite the fact that it is not as sterically crowded as 6-(3,5-dimethylpyrazol-1-yl)purine, an artificial nucleobase that had previously been suggested for the recognition of nucleic acid sequences via the formation of a metal-mediated base pair. Hence, the additional methyl groups of 6-(3,5-dimethylpyrazol-1-yl)purine may not be required for the specific recognition of the complementary nucleobase.

Highlights

Nucleic acids are increasingly being used as building blocks in nanotechnology, owing to their superb and highly predictable self-assembly, their stiffness, and the ease of their modification [1]
A stabilizing 6PP–Ag(I)–T base pair is formed with a complementary thymine (T) residue
It is interesting to note that 6PP is capable of differentiating between the pyrimidine moieties despite the fact that it is not as sterically crowded as 6-(3,5-dimethylpyrazol-1-yl)purine, an artificial nucleobase that had previously been suggested for the recognition of nucleic acid sequences via the formation of a metal-mediated base pair

Summary

Introduction

Nucleic acids are increasingly being used as building blocks in nanotechnology, owing to their superb and highly predictable self-assembly, their stiffness, and the ease of their modification [1]. The resulting metal-containing nucleic acids have found manifold applications, including their use as sensors [12], in expanding the genetic code [13], in modifying the charge transfer capabilities of DNA [14,15], in the generation of metal nanoclusters [16], and in the recognition of other nucleic acid sequences [17] In the latter context, a series of purine derivatives with appended donor moieties have recently been proposed as artificial nucleobases for the specific recognition of a complementary canonical nucleobase via the formation of a metal-mediated base pair [18,19,20,21]. The similarities between 6-(3,5-dimethylpyrazol-1-yl)purine and 6-pyrazol-1-yl-purine suggest that the methyl substituents on the pyrazole moiety may not be required to achieve the specific recognition of a complementary nucleobase

Oligonucleotide Synthesis and Characterization

Spectroscopy