Structural perturbations in DNA caused by bis-intercalation of ditercalinium visualised by atomic force microscopy
AUTOR(ES)
Berge, Torunn
FONTE
Oxford University Press
RESUMO
Atomic force microscopy (AFM) has been used to examine perturbations in the tertiary structure of DNA induced by the binding of ditercalinium, a DNA bis-intercalator with strong anti-tumour properties. We report AFM images of plasmid DNA of both circular and linearised forms showing a difference in the formation of supercoils and plectonemic coils caused at least in part by alterations in the superhelical stress upon bis-intercalation. A further investigation of the effects of drug binding performed with 292 bp mixed-sequence DNA fragments, and using increment in contour length as a reliable measure of intercalation, revealed saturation occurring at a point where sufficient drug was present to interact with every other available binding site. Moment analysis based on the distribution of angles between segments along single DNA molecules showed that at this level of bis-intercalation, the apparent persistence length of the molecules was 91.7 ± 5.7 nm, approximately twice as long as that of naked DNA. We conclude that images of single molecules generated using AFM provide a valuable supplement to solution-based techniques for evaluation of physical properties of biological macromolecules.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=117064Documentos Relacionados
- Site selective bis-intercalation of a homodimeric thiazole orange dye in DNA oligonucleotides.
- Bis-intercalation of a homodimeric thiazole orange dye in DNA in symmetrical pyrimidine-pyrimidine-purine-purine oligonucleotides.
- H-NS mediated compaction of DNA visualised by atomic force microscopy
- Atomic force microscopy of DNA in aqueous solutions.
- Atomic force microscopy of biochemically tagged DNA.