Oligonucleotide Labeling: Synthesis of a New Spin-Labeled 2′-Deoxyguanosine Analogue

Abstract

in order to achieve an EPR sensitive probe for DNA, 3-carboxy-Proxyl free radical was linked to O-6 of dG through a five-atoms-tether. The modified base was incorporated into a 30-mer ODN, then annealed to its complementary DNA strand. Hydrodinamic parameters show only a slight destabilization with respect to the equivalent unlabeled hybrid. EPR could monitor the hybrid formation showing a progressive enlargement of the upfield signal in passing from the labeled ss- to the ds-30-mer.