title: Nitroxide-labeled pyrimidines for non-covalent spin-labeling of abasic sites in DNA and RNA duplexes.
abstract: Non-covalent and site-directed spin labeling gives easy access to spin-labeled nucleic acids for the study of their structure and dynamics by electron paramagnetic resonance (EPR) spectroscopy. In a search for improved spin labels for non-covalent binding to abasic sites in duplex DNA and RNA, ten pyrimidine-derived spin labels were prepared in good yields and their binding was evaluated by continuous wave (CW)-EPR spectroscopy. Most of the spin labels showed lower binding affinity than the previously reported label ç towards abasic sites in DNA and RNA. The most promising labels were triazole-linked spin labels and a pyrrolocytosine label. In particular, the N1-ethylamino derivative of a triazole-linked uracil spin label binds fully to both DNA and RNA containing an abasic site. This is the first example of a spin label that binds fully through non-covalent interactions with an abasic site in RNA.
authors.affiliation: University of Iceland, Department of Chemistry, Science Institute, Dunhaga 3, 107 Reykjavik, Iceland. snorrisi@hi.is.
authors.forename: Sandip A
authors.initials: SA
authors.lastname: Shelke
authors.forename: Gunnar B
authors.initials: GB
authors.lastname: Sandholt
authors.forename: Snorri Th
authors.initials: ST
authors.lastname: Sigurdsson
mesh_terms: D004247:DNA / Q000737:chemistry*; D015394:Molecular Structure; D009589:Nitrogen Oxides / Q000737:chemistry*; D011743:Pyrimidines / Q000138:chemical synthesis / Q000737:chemistry*; D012313:RNA / Q000737:chemistry*
chemical_list: D009589:Nitrogen Oxides; D011743:Pyrimidines; D012313:RNA; D004247:DNA