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1 May 1990 Some aspects of the photophysics of DNA
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We have made room-temperature measurements of transfer of electronic energy in calf thymus DNA in which 75% of the guanine residues are methylated at position N-7. The methylated residues absorb light at much longer wavelengths than the nonmethylated residues and, as a result, constitute an irreversible energy trap. For excitation at 270 nm the efficiency of intrastrand transfer is found to be 0.31. We note that this is the first measurement of the efficiency of energy transfer along the double helix of a nucleic acid. In addition, the data have been simulated by using a stochastic model in terms of Förster's theory for dipole-dipole transfer. The adequacy of the latter is discussed. Preliminary measurements of the dependence of the fluorescence spectrum and of the fluorescence anisotropy of the alternating polynucleotide poly(dA-dT).poly(dA-dT) on the excitation wavelength and temperature are interpreted in terms of emission from molecular complexes formed between A and T residues.
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Solon Georghiou, Guangyuan Ge, Ralph D. Weidner, Shen Zhu, and C. R. Huang "Some aspects of the photophysics of DNA", Proc. SPIE 1204, Time-Resolved Laser Spectroscopy in Biochemistry II, (1 May 1990);

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