Physics Commons^™

Mono- And Trivalent Ions Around Dna: A Small-Angle Scattering Study Of Competition And Interactions, Kurt Andresen, Xiangyun Qiu, Suzette A. Pabit, Jessica S. Lamb, Hye Yoon Park, Lisa W. Kwok, Lois Pollack

Physics and Astronomy Faculty Publications

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 …