Europhys. Lett.
Volume 68, Number 6, December 2004
Page(s) 894 - 900
Section Interdisciplinary physics and related areas of science and technology
Published online 12 November 2004
Europhys. Lett., 68 (6), pp. 894-900 (2004)
DOI: 10.1209/epl/i2004-10272-8

DNA condensation, redissolution and mesocrystals induced by tetravalent counterions

E. Allahyarov1, 2, 3, H. Löwen1 and G. Gompper2

1  Institut für Theoretische Physik II, Heinrich-Heine-Universität Düsseldorf D-40225 Düsseldorf, Germany
2  Institut für Festkörperforschung, Forschungszentrum Jülich D-52425 Jülich, Germany
3  Institute for High Temperatures, Russian Academy of Sciences Izhorskaya street 13/19, 127412 Moscow, Russia

received 10 June 2004; accepted in final form 14 October 2004
published online 12 November 2004

The distance-resolved effective interaction potential between two parallel DNA molecules is calculated by computer simulations with explicit tetravalent counterions and monovalent salt. Adding counterions first yields an attractive minimum in the potential at short distances which then disappears in favor of a shallower minimum at larger separations. The resulting phase diagram includes a DNA condensation and redissolution transition and a stable mesocrystal with an intermediate lattice constant for high counterion concentration.

87.15.Kg - Molecular interactions; membrane-protein interactions.
61.20.Ja - Computer simulation of liquid structure.
82.70.Dd - Colloids.

© EDP Sciences 2004