1968/01/15 by Keiichi Imakubo
Biochemistry, Genetics and Molecular Biology · Engineering · #DNA and Nucleic Acid Chemistry #Advanced biosensing and bioanalysis techniques #Muon and positron interactions and applications
paper · doi:10.1143/jpsj.24.143
In order to obtain detailed information on the u.v.-induced energy transfer and the excited states in DNA, the fluorescence and phosphorescence of nucleosides, nucleotides, and DNA in 1:1 by volume of ethylene glycol-water at 77°K have been studied. Our main conclusions are: (1) At neutral pH, both the purine derivatives and the pyrimidine derivatives phosphoresce, with the lifetimes of 1.25–2.45 sec and 0.45–0.65 sec, respectively. (2) The lowest triplet state energy of the five bases decreases in the following order: cytosine, guanine, adenine, uracil, thymine. (3) The phosphorescence of DNA is composed of the two components which originate from the neutral thymine and the neutral adenine, but the lowest triplet state of DNA is almost located on the neutral thymine bases (more than 95%). (4) The fluorescence of DNA, which is red-shifted by about 35 mµ from an equimolar mixture of its constituent nucleotides, is understood in terms of the interaction of bases stacked on the same strand in the first excited singlet state. (5) The energy transfer in DNA takes place not via the hydrogen bond between strands but along the strand.