Double-helical DNA is particularly resistant to bending and twisting deformations. These elastic properties have important implications for the packaging and function of DNA in living cells. Atomic force microscopy (AFM) was used to examine the morphological effects of small molecule binding and report changes in the physical properties of intrinsically straight DNA molecules. The persistence length and polymer extension, biophysical parameters that describe the DNA polymer, were characterized in the presence of different DNA binding ligands. Analysis with the wormlike chain polymer model robustly showed a 2- to 3-fold increase in the apparent persistence length for DNA molecules upon intercalation with chloroquine, ethidium bromide, or acridine. In addition, an analysis of the normal bending modes of the static molecules corroborated these results. This approach of measuring ligand binding effects on DNA physical properties using a model system of intrinsically straight DNA is applicable to other DNA binding molecules and other modes of DNA interaction.

Characterization of the elastic properties of duplex DNA bound by small molecules

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.