Phosphorescence in Nucleotides and Nucleic Acids

摘要

As a sequel to earlier work by Steele and Szenthyphen;Gyouml;rgyi, the phosphorescence of DNA, polyadenylic acids, and individual nucleotides in a watermdash;glycerine glass at 77deg;K has been studied. Under these conditions, our experiments lead to the following conclusions: (1) Purine bases phosphoresce but pyrimidine bases do not, (2) the emission from DNA is the sum of independent emissions from guanine and adenine, and (3) if certain assumptions are valid, the triplet excitation is a delocalized exciton. Addition of paramagnetic ions to a polynucleotide results in quenching of the phosphorescence. If this effect is studied quantitatively, the diffusion coefficient of the exciton can be measured. This diffusion coefficient should be sensitive to the degree of order in the polynucleotides and to their composition.