Orthorhombic crystal structure of the A-DNA octamer d(GTACGTAC). Comparison with the tetragonal structure

Eur J Biochem. 1993 Apr 15;213(2):673-82. doi: 10.1111/j.1432-1033.1993.tb17807.x.


The X-ray crystal structure of the double-helical A-DNA octanucleotide d(GTACGTAC) has been solved by molecular replacement and refined to a resolution of 0.219 nm. The final R-factor is equal to 16.1% for 1516 observed reflections with F > 4 sigma(F). The sequence crystallizes as an A-DNA-type double helix in the orthorhombic space group P2(1)2(1)2, with one duplex molecule solvated by 66 water molecules in the asymmetric unit. Cell parameters are a = 3.860 nm, b = 5.082 nm, c = 2.174 nm. It is the first time that such a crystal form has been observed. This orthorhombic structure has been compared with the tetragonal structure of the same oligonucleotide. It adopts a bent structure with an unusual packing between symmetry-related molecules.

Publication types

  • Comparative Study

MeSH terms

  • Base Sequence
  • DNA / chemistry*
  • Hydrogen Bonding
  • Models, Molecular
  • Molecular Sequence Data
  • Nucleic Acid Conformation*
  • Oligodeoxyribonucleotides / chemistry*
  • X-Ray Diffraction / methods


  • Oligodeoxyribonucleotides
  • DNA