title: Fractal dimension and localization of DNA knots.
abstract: The scaling properties of DNA knots of different complexities were studied by atomic force microscope. Following two different protocols DNA knots are adsorbed onto a mica surface in regimes of (i) strong binding, that induces a kinetic trapping of the three-dimensional (3D) configuration, and of (ii) weak binding, that permits (partial) relaxation on the surface. In (i) the radius of gyration of the adsorbed DNA knot scales with the 3D Flory exponent nu approximately 0.60 within error. In (ii), we find nu approximately 0.66, a value between the 3D and 2D (nu=3/4) exponents. Evidence is also presented for the localization of knot crossings in 2D under weak adsorption conditions.
authors.affiliation: Laboratory of Physics of Living Matter, IPMC, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Erika
authors.initials: E
authors.lastname: Ercolini
authors.forename: Francesco
authors.initials: F
authors.lastname: Valle
authors.forename: Jozef
authors.initials: J
authors.lastname: Adamcik
authors.forename: Guillaume
authors.initials: G
authors.lastname: Witz
authors.forename: Ralf
authors.initials: R
authors.lastname: Metzler
authors.forename: Paolo
authors.initials: P
authors.lastname: De Los Rios
authors.forename: Joaquim
authors.initials: J
authors.lastname: Roca
authors.forename: Giovanni
authors.initials: G
authors.lastname: Dietler
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D004278:DNA, Superhelical / Q000737:chemistry* / Q000648:ultrastructure*; D017709:Fractals; D018625:Microscopy, Atomic Force; D009690:Nucleic Acid Conformation
chemical_list: D004278:DNA, Superhelical