Abstract
Formation of mixed-ligand Pd2+ complexes between canonical nucleoside 5'-monophosphates and five metal-ion-binding nucleoside analogs has been studied by 1H-NMR spectroscopy to test the ability of these nucleoside surrogates to discriminate between unmodified nucleobases by Pd2+-mediated base pairing. The nucleoside analogs studied included 2,6-bis(3,5-dimethylpyrazol-1-yl)-, 2,6-bis(1-methylhydrazinyl)- and 6-(3,5-dimethylpyrazol-1-yl)-substituted 9-(β-d-ribofuranosyl)purines 1–3, and 2,4-bis(3,5-dimethylpyrazol-1-yl)- and 2,4-bis(1-methylhydrazinyl)-substituted 5-(β-d-ribofuranosyl)-pyrimidines 4–5. Among these, the purine derivatives 1-3 bound Pd2+ much more tightly than the pyrimidine derivatives 4, 5 despite apparently similar structures of the potential coordination sites. Compounds 1 and 2 formed markedly stable mixed-ligand Pd2+ complexes with UMP and GMP, UMP binding favored by 1 and GMP by 2. With 3, formation of mixed-ligand complexes was retarded by binding of two molecules of 3 to Pd2+.
Highlights
It has been well established that linear-coordinating Hg2+ and Ag+ ions may stabilize TT and CC mismatches within oligonucleotide duplexes while square-planar-coordinating Cu2+ ion is able to bridge various modified metal-ion-binding bases on opposite strands [1,2,3]
Much less is known about discrimination between canonical nucleobases by oligonucleotide probes incorporating metal-ion-binding surrogate bases
We have previously tried to evaluate the formation of mixed-ligand Pd2+ complexes between some metal ion binding nucleoside analogs and pyrimidine nucleosides [9]
Summary
It has been well established that linear-coordinating Hg2+ and Ag+ ions may stabilize TT and CC mismatches within oligonucleotide duplexes while square-planar-coordinating Cu2+ ion is able to bridge various modified metal-ion-binding bases on opposite strands [1,2,3]. Much less is known about discrimination between canonical nucleobases by oligonucleotide probes incorporating metal-ion-binding surrogate bases. We have previously tried to evaluate the formation of mixed-ligand Pd2+ complexes between some metal ion binding nucleoside analogs and pyrimidine nucleosides [9]. To learn more about the discrimination power of Pd2+ complexes, we report on NMR studies concerning formation of mixed-ligand Pd2+ complexes between metal-ionbinding nucleosides 1–5 (Figure 1) and six nucleoside 5'-monophosphates (NMPs, Figure 2)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have