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Multimerization-cyclization of DNA fragments as a method of conformational analysis
A A Podtelezhnikov1, C Mao, N C Seeman
1Department of Chemistry, New York University, New York, NY 10003, USA.
Biophysical Journal
|October 29, 2000
Summary
This study introduces a quantitative method to analyze DNA fragment bending by determining j-factors from ligation products. This approach accurately measures DNA conformational parameters like bend angle and rigidity.
Area of Science:
- Molecular Biology
- Biophysics
- Structural Biology
Background:
- DNA fragment ligation produces linear and circular multimers.
- Product distribution in ligation reactions can indicate DNA bending due to modifications or ligands.
- Existing methods for analyzing DNA bending are often qualitative.
Purpose of the Study:
- To develop a rigorous quantitative approach for analyzing DNA fragment bending using ligation data.
- To introduce the concept and determination of j-factors for DNA multimers.
- To link j-factors to key DNA conformational parameters.
Main Methods:
- Determining j-factors from the distribution of ligation products using a system of differential equations.
- Calculating DNA conformational parameters (bend angle, bending rigidity, total twist) from j-factors using empirical equations.
- Validating the approach with simulated and experimental data from DNA fragments with A-tracts.
Main Results:
- A novel quantitative method for analyzing DNA fragment bending was developed.
- The method successfully determines j-factors, which are coefficients in reaction kinetics.
- DNA conformational parameters, including the A-tract DNA bend angle, were accurately determined and validated.
Conclusions:
- The developed quantitative approach provides a rigorous method for assessing DNA fragment conformation.
- J-factors serve as crucial parameters linking ligation product distribution to DNA structural properties.
- The method is effective for analyzing DNA fragments with structural irregularities like A-tracts.