DNA 结的分形维数与定位

Fractal dimension and localization of DNA knots.

作者信息

Ercolini Erika, Valle Francesco, Adamcik Jozef, Witz Guillaume, Metzler Ralf, De Los Rios Paolo, Roca Joaquim, Dietler Giovanni

机构信息

Laboratory of Physics of Living Matter, IPMC, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.

出版信息

Phys Rev Lett. 2007 Feb 2;98(5):058102. doi: 10.1103/PhysRevLett.98.058102. Epub 2007 Jan 29.

DOI:10.1103/PhysRevLett.98.058102

PMID:17358904

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.

摘要

利用原子力显微镜研究了不同复杂程度的DNA结的标度性质。按照两种不同的方案，DNA结在以下两种情况下吸附到云母表面：（i）强结合，这会导致三维（3D）构型的动力学捕获；（ii）弱结合，这允许在表面上（部分）弛豫。在（i）中，吸附的DNA结的回转半径在误差范围内与3D弗洛里指数ν≈0.60成比例。在（ii）中，我们发现ν≈0.66，该值介于3D和2D（ν = 3/4）指数之间。还给出了在弱吸附条件下二维中结交叉定位的证据。