title: Optically detected zero field magnetic resonance characterization of a bromine atom-containing polynucleotide, poly(dA-br5dU).
abstract: Phosphorescence and optically detected zero field magnetic resonance ( ODMR ) spectra are reported for a bromine atom-containing polynucleotide, poly(dA- br5dU ). The triplet state luminescence of poly(dA- br5dU ) is dominated by the phosphorescence of the bromouracil base which possesses sub-millisecond triplet lifetimes. Characteristic multiple slow passage ODMR transitions, which are observed in both br5dUrd and poly(dA- br5dU ), are assigned to the triplet state of bromouracil. In addition, an abnormally-perturbed adenine triplet state, which is not apparent in the phosphorescence spectrum of poly(dA- br5dU ), is detected and identified by its slow passage ODMR and amplitude-modulated phosphorescence microwave double resonance spectra. It is proposed that the perturbed adenine is a minor component of the polynucleotide structure which is present in regions of altered stacking induced by the high polarizability of the Br atom.
mesh_terms: D000225:Adenine; D001973:Bromodeoxyuridine; D003854:Deoxyribonucleotides; D008163:Luminescent Measurements; D009682:Magnetic Resonance Spectroscopy; D008872:Microwaves; D011061:Poly A; D011063:Poly A-U; D011089:Polydeoxyribonucleotides; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D003854:Deoxyribonucleotides; D011089:Polydeoxyribonucleotides; D011063:Poly A-U; D011061:Poly A; C015465:poly(dA); C020468:poly(d(A-U)); D001973:Bromodeoxyuridine; D000225:Adenine