Daunomycin intercalation stabilizes distinct backbone conformations of DNA

J Biomol Struct Dyn. 2004 Apr;21(5):713-24. doi: 10.1080/07391102.2004.10506961.

Abstract

Daunomycin is a widely used antibiotic of the anthracycline family. In the present study we reveal the structural properties and important intercalator-DNA interactions by means of molecular dynamics. As most of the X-ray structures of DNA-daunomycin intercalated complexes are short hexamers or octamers of DNA with two drug molecules per doublehelix we calculated a self complementary 14-mer oligodeoxyribonucleotide duplex d(CGCGCGATCGCGCG)2 in the B-form with two putative intercalation sites at the 5'-CGA-3' step on both strands. Consequently we are able to look at the structure of a 1:1 complex and exclude crystal packing effects normally encountered in most of the X-ray crystallographic studies conducted so far. We performed different 10 to 20 ns long molecular dynamics simulations of the uncomplexed DNA structure, the DNA-daunomycin complex and a 1:2 complex of DNA-daunomycin where the two intercalator molecules are stacked into the two opposing 5'-CGA-3' steps. Thereby--in contrast to X-ray structures--a comparison of a complex of only one with a complex of two intercalators per doublehelix is possible. The chromophore of daunomycin is intercalated between the 5'-CG-3' bases while the daunosamine sugar moiety is placed in the minor groove. We observe a flexibility of the dihedral angle at the glycosidic bond, leading to three different positions of the ammonium group responsible for important contacts in the minor groove. Furthermore a distinct pattern of BI and BII around the intercalation site is induced and stabilized. This indicates a transfer of changes in the DNA geometry caused by intercalation to the DNA backbone.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Computer Simulation
  • Crystallography, X-Ray
  • DNA / chemistry
  • DNA / drug effects*
  • Daunorubicin / chemistry
  • Daunorubicin / pharmacology*
  • Intercalating Agents / pharmacology*
  • Models, Molecular
  • Nucleic Acid Conformation / drug effects*
  • Time Factors

Substances

  • Intercalating Agents
  • DNA
  • Daunorubicin