Document Type
Article
Publication Date
12-2004
Department 1
Physics
Abstract
The competition of monovalent and divalent cations for proximity to negatively charged DNA is of biological importance and can provide strong constraints for theoretical treatments of polyelectrolytes. Resonant x-ray scattering experiments have allowed us to monitor the number and distribution of each cation in a mixed ion cloud around DNA. These measurements provide experimental evidence to support a general theoretical prediction: the normalized distribution of each ion around polyelectrolytes remains constant when ions are mixed at different ratios. In addition, the amplitudes of the scattering signals throughout the competition provide a measurement of the surface concentration parameter that predicts the competition behavior of these cations. The data suggest that ion size needs to be taken into account in applying Poisson-Boltzmann treatments to polyelectrolytes such as DNA.
Copyright Note
This is the publisher's version of the work. This publication appears in Gettysburg College's institutional repository by permission of the copyright owner for personal use, not for redistribution.
Recommended Citation
Andresen, K., Das, R., Park, H.Y., Smith, H., Kwok, L.W., Lamb, J.S., Kirkland, E.J., Herschlag, D., Finkelstein, K.D., & Pollack, L. (2004). Spatial distribution of competing ions around DNA in solution. Physical Review Letters, 93(248103). http://dx.doi.org/10.1103/PhysRevLett.93.248103
Required Publisher's Statement
Copyright 2004, The American Physical Society. First published as K Andresen et al, Spatial Distribution of Competing Ions around DNA in Solution, Physical Review Letters, 93, 248103, doi: 10.1103/PhysRevLett.93.248103.