Title
Mono- and Trivalent Ions around DNA: A Small-Angle Scattering Study of Competition and Interactions
Document Type
Article
Publication Date
7-2008
Department 1
Physics
Abstract
The presence of small numbers of multivalent ions in DNA-containing solutions results in strong attractive forces between DNA strands. Despite the biological importance of this interaction, e.g., DNA condensation, its physical origin remains elusive.Wecarried out a series of experiments to probe interactions between short DNA strands as small numbers of trivalent ions are included in a solution containing DNA and monovalent ions. Using resonant (anomalous) and nonresonant small angle x-ray scattering, we coordinated measurements of the number and distribution of each ion species around the DNA with the onset of attractive forces between DNA strands. DNA-DNA interactions occur as the number of trivalent ions increases. Surprisingly good agreement is found between data and size-corrected numerical Poisson-Boltzmann predictions of ion competition for non- and weakly interacting DNAs. We also obtained an estimate for the minimum number of trivalent ions needed to initiate DNA-DNA attraction.
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
Kurt, A., Xiangyun, Q., Suzette A., P., Jessica S., L., Hye Yoon, P., Lisa W., K., & Lois, P. (2008). Mono- and Trivalent Ions around DNA: A Small-Angle Scattering Study of Competition and Interactions. Biophysical Journal, 95, 287-295. http://dx.doi.org/10.1529/biophysj.107.123174
Required Publisher's Statement
Copyright 2008, The Biophysical Society