Dependence of DNA persistence length on ionic strength of solutions with monovalent and divalent salts: a joint theory-experiment study

Abstract

Using high-throughput Tethered Particle Motion single molecule experiments, the double-stranded DNA persistence length, $L_p$, is measured in solutions with Na${}^{+}$ and Mg${}^{2+}$ ions of various ionic strengths, $I$. Several theoretical equations for $L_p(I)$ are fitted to the experimental data, but no decisive theory is found which fits all the $L_p$ values for the two ion valencies. Properly extracted from the particle trajectory using simulations, $L_p$ varies from 30~nm to 55~nm, and is compared to previous experimental results. For the Na${}^{+}$ only case, $L_p$ is an increasing concave function of $I^{-1}$, well fitted by Manning's electrostatic stretching approach, but not by classical Odjik-Skolnick-Fixman theories with or without counter-ion condensation. With added Mg${}^{2+}$ ions, $L_p$ shows a marked decrease at low $I$, interpreted as an ion-ion correlation effect, with an almost linear law in $I^{-1}$, fitted by a proposed variational approach.

References in corpus (11)

• Variational charge renormalization in charged systems
• Excluded-Volume Effects in Tethered-Particle Experiments: Bead Size Matters
• Collapse of Stiff Polyelectrolytes due to Counterion Fluctuations
• Variational approach for electrolyte solutions: from dielectric interfaces to charged nanopores
• Quantification and Correction of Systematic Errors Due to Detector Time-Averaging in Single-Molecule Tracking Experiments
• Variational theory for a single polyelectrolyte chain revisited
• Thermal denaturation of fluctuating finite DNA chains: the role of bending rigidity in bubble nucleation
• Probing DNA conformational changes with high temporal resolution by Tethered Particle Motion
• Negative electrostatic contribution to the bending rigidity of charged membranes and polyelectrolytes screened by multivalent counterions
• Polyelectrolyte Persistence Length: Attractive Effect of Counterion Correlations and Fluctuations
• Effect of magnesium ions on dielectric relaxation in semidilute DNA aqueous solutions

Cited by in corpus (8)

• Sequence-dependent Three Interaction Site (TIS) Model for Single and Double-stranded DNA
• What do we know about DNA mechanics so far?
• Harnessing Avidity: Quantifying Entropic and Energetic Effects of Linker Length and Rigidity Required for Multivalent Binding of Antibodies to HIV-1 Spikes
• How do polymers stretch in capillary-driven extensional flows?
• Determination of single-bond association kinetics by tethered particle motion: concept and simulations
• Ion-dependent DNA Configuration in Bacteriophage Capsids
• Statistical physics and mesoscopic modeling to interpret tethered particle motion experiments
• Sensing Translocating Polymers via Induced Magnetic Fields