Mono- and trivalent ions around DNA: a small-angle scattering study of competition and interactions |
| |
Authors: | Andresen Kurt Qiu Xiangyun Pabit Suzette A Lamb Jessica S Park Hye Yoon Kwok Lisa W Pollack Lois |
| |
Institution: | School of Applied and Engineering Physics, Cornell University, Ithaca, New York |
| |
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. We carried 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. |
| |
Keywords: | |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|