DNA attraction in monovalent and divalent electrolytes.
The dependence of the effective force on the distance between two DNA molecules was directly computed from a set of extensive all-atom molecular dynamics simulations. The simulations revealed that in a monovalent electrolyte the effective force is repulsive at short and long distances but can be attractive in the intermediate range. This attractive force is, however, too weak (approximately 5 pN per turn of a DNA helix) to induce DNA condensation in the presence of thermal fluctuations. In divalent electrolytes, DNA molecules were observed to form a bound state, where Mg(2+) ions bridged minor groves of DNA. The effective force in divalent electrolytes was predominantly attractive, reaching a maximum of 42 pN per one turn of a DNA helix.
Luan
Binquan
B
University of Illinois at Urbana-Champaign, Department of Physics, 1110 West Green Street, Urbana, Illinois 61801, USA.
Aksimentiev
Aleksei
A
D003198:Computer Simulation; D004247:DNA / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation
D004573:Electrolytes; D004247:DNA