Versatile Analysis of DNA-Biomolecule Interactions in Solution by Hydrodynamic Separation and Single Molecule...

Area of Science:

• Biochemistry
• Molecular Biology
• Analytical Chemistry

Background:

• DNA interacts with numerous molecules, exhibiting diverse binding characteristics.
• Accurate characterization of these interactions is crucial for understanding biological processes.
• Existing methods may lack the sensitivity, quantitation, or versatility needed for comprehensive analysis.

Purpose of the Study:

• To develop and validate a sensitive, quantitative, and versatile platform for analyzing DNA-biomolecule interactions and DNA conformational changes in free solution.
• To enable high-throughput analysis using minimal sample volumes.
• To characterize binding behavior, including affinity, stoichiometry, and cooperativity.

Main Methods:

• Single-molecule free solution hydrodynamic separation to differentiate bound and unbound DNA based on size changes.
• Single-molecule detection for quantitative analysis of binding states.
• Stacked injection schemes to enhance throughput.
• Application to DNA-protein binding (E. coli single-stranded binding protein) and DNA-small molecule interactions (spermidine-induced condensation).

Main Results:

• The platform successfully quantifies DNA-protein binding stoichiometry and cooperativity, demonstrating dependence on DNA length.
• Direct competition assays verified differences in binding characteristics.
• Hydrodynamic mobility and single-molecule burst analysis characterized DNA condensation by spermidine, assessing globule size and DNA packing.
• The platform provides sensitive and quantitative evaluation of diverse biomolecular interactions and DNA properties.

Conclusions:

• The developed platform offers a versatile and sensitive tool for the quantitative evaluation of DNA-biomolecule interactions and DNA conformational changes.
• It enables detailed characterization of binding parameters like affinity, stoichiometry, and cooperativity.
• This technology has broad applications in molecular biology, biochemistry, and drug discovery for analyzing complex molecular interactions.