Spatial distribution of competing ions around DNA in solution

K. Andresen, R. Das, H. Y. Park, H. Smith, L. W. Kwok, J. S. Lamb, E. J. Kirkland, D. Herschlag, K. D. Finkelstein, L. Pollack

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The competition of monovalent and divalent cations for proximity to negatively charged DNA in solution was analyzed. The number and distribution of each cation in a mixed ion cloud around DNA was monitored using resonant x-ray scattering experiments. A measurement of the surface concentration parameter that predicts the competition behavior of these cations was provided by the amplitudes of the scattering signals throughout the competition. It was suggested by the data that ion size needs to be taken into account in applying Poisson-Boltzmann treatments to polyelectrolytes such as DNA.

Original languageEnglish (US)
Article number248103
JournalPhysical review letters
Issue number24
StatePublished - Dec 10 2004
Externally publishedYes

Bibliographical note

Funding Information:
We thank Vijay Pande for discussions and John Nagle and Ernie Fontes for assistance with the experiment. This research is funded by the NIH through P01-GM066275, the NSF through MCB-0347220 and the NBTC at Cornell, and NASA through NAG8-1778. CHESS is supported by the NSF and the NIH/NIGMS under Grant No. DMR-9713424. The CNF is supported by the NSF, Cornell University and industrial affiliates.


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