Measuring inter-DNA potentials in solution.
Interactions between short strands of DNA can be tuned from repulsive to attractive by varying solution conditions and have been quantified using small angle x-ray scattering techniques. The effective DNA interaction charge was extracted by fitting the scattering profiles with the generalized one-component method and inter-DNA Yukawa pair potentials. A significant charge is measured at low to moderate monovalent counterion concentrations, resulting in strong inter-DNA repulsion. The charge and repulsion diminish rapidly upon the addition of divalent counterions. An intriguing short range attraction is observed at surprisingly low divalent cation concentrations, approximately 16 mM Mg2+. Quantitative measurements of inter-DNA potentials are essential for improving models of fundamental interactions in biological systems.
Qiu
Xiangyun
X
School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA.
Kwok
Lisa W
LW
Park
Hye Yoon
HY
Lamb
Jessica S
JS
Andresen
Kurt
K
Pollack
Lois
L
D004277:DNA, Single-Stranded / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry*; D008958:Models, Molecular; D009010:Monte Carlo Method; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D012996:Solutions / Q000737:chemistry; D055672:Static Electricity; D014961:X-Ray Diffraction
D004277:DNA, Single-Stranded; D012996:Solutions; D008274:Magnesium