title: The promotion of secondary structures in single-stranded DNA by drugs that bind to duplex DNA: an atomic force microscopy study.
abstract: We study the behavior of single-stranded DNA (ssDNA) in the presence of well-known drugs with either an intercalating binding mode, such as daunorubicin, actinomycin D, and chloroquine, or a minor groove binding mode, such as netropsin and berenil, by atomic force microscopy (AFM). At very low salt conditions, ssDNA molecules adopt an unstructured conformation without secondary structures. We observe that under these conditions additions of drugs that bind to double-stranded DNA (dsDNA) promote the formation of secondary structures in ssDNA. Furthermore, with an increase of concentration of the drugs, the extension as well as the thermal stabilization of these hairpins was observed.
authors.affiliation: Laboratoire de Physique de la Matière Vivante, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Jozef
authors.initials: J
authors.lastname: Adamcik
authors.forename: Francesco
authors.initials: F
authors.lastname: Valle
authors.forename: Guillaume
authors.initials: G
authors.lastname: Witz
authors.forename: Kristian
authors.initials: K
authors.lastname: Rechendorff
authors.forename: Giovanni
authors.initials: G
authors.lastname: Dietler