Inter-DNA Attraction Mediated by Divalent Counterions
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States)
Can nonspecifically bound divalent counterions induce attraction between DNA strands? Here, we present experimental evidence demonstrating attraction between short DNA strands mediated by Mg{sup 2+} ions. Solution small angle x-ray scattering data collected as a function of DNA concentration enable model independent extraction of the second virial coefficient. As the [Mg{sup 2+}] increases, this coefficient turns from positive to negative reflecting the transition from repulsive to attractive inter-DNA interaction. This surprising observation is corroborated by independent light scattering experiments. The dependence of the observed attraction on experimental parameters including DNA length provides valuable clues to its origin.
- OSTI ID:
- 20957907
- Journal Information:
- Physical Review Letters, Vol. 99, Issue 3; Other Information: DOI: 10.1103/PhysRevLett.99.038104; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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