A novel assay for drug-DNA binding mode, affinity, and exclusion number: scanning force microscopy.

AUTOR(ES)

Coury, J E

RESUMO

Determining the mode-of-binding of a DNA ligand is not always straightforward. Here, we establish a scanning force microscopic assay for mode-of-binding that is (i) direct: lengths of individual DNA-ligand complexes are directly measured; (ii) rapid: there are no requirements for staining or elaborate sample preparation; and (iii) unambiguous: an observed increase in DNA length upon addition of a ligand is definitive evidence for an intercalative mode-of-binding. Mode-of-binding, binding affinity, and site-exclusion number are readily determined from scanning force microscopy measurements of the changes in length of individual drug-DNA complexes as a function of drug concentration. With this assay, we resolve the ambiguity surrounding the mode of binding of 2,5-bis(4-amidinophenyl) furan (APF) to DNA and show that it binds to DNA by nonintercalative modes. APF is a member of an important class of aromatic dicationic drugs that show significant activity in the treatment of Pneumocystis carinii pneumonia, an opportunistic infection that is the leading cause of death in AIDS patients.

Documentos Relacionados

• Enthalpy-entropy compensations in drug-DNA binding studies.
• Vertical dimension of hydrated biological samples in tapping mode scanning force microscopy.
• Chirality of DNA supercoiling assigned by scanning force microscopy.
• The anticancer drug–DNA complex: Femtosecond primary dynamics for anthracycline antibiotics function
• DNA binding to mica correlates with cationic radius: assay by atomic force microscopy.