1H NMR study of the exchangeable protons of the duplex d(GCGTTGCG).d(CGCAACGC) containing a thymine photodimer

Nucleic Acids Res. 1987 Jun 11;15(11):4645-53. doi: 10.1093/nar/15.11.4645.


A comparison is presented of the imino proton NMR spectra of the double stranded octamer d(GCGTTGCG).d(CGCAACGC) and the same octamer in which the two central thymine residues occur as a cis-syn thymine dimer. Except for the terminal base pairs all imino protons were detected and assigned in the NMR spectrum. The spectra show that in the thymine dimer duplex, contrary to common belief, all base pairs occur in a hydrogen bonded form, although the hydrogen bonds of the two central AT base pairs are substantially weakened. The melting temperature decreases about 13 degrees C on thymine dimer formation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Imines
  • Magnetic Resonance Spectroscopy
  • Nucleic Acid Conformation*
  • Nucleic Acid Denaturation
  • Oligodeoxyribonucleotides* / chemical synthesis
  • Protons
  • Pyrimidine Dimers*
  • Temperature


  • Imines
  • Oligodeoxyribonucleotides
  • Protons
  • Pyrimidine Dimers