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Eukaryotic DNAs in solution contain characteristic components of tertiary structure.
K E Reinert1, K Geller, G Burckhardt
1Department of Biophysical Chemistry, Institute of Mikrobiology and Experimental Therapy, Jena, Germany.
Journal of Biomolecular Structure & Dynamics
|December 1, 1991
Summary
Eukaryotic DNA exhibits secondary-helix components, leading to elongation effects influenced by tertiary structures. Prokaryotic DNA shows smaller effects, likely due to base breathing, indicating distinct DNA structural mechanisms.
Area of Science:
- Molecular Biology
- Biophysics
Background:
- Previous studies indicated an electrostatically driven increase in DNA contour length.
- This effect was observed in calf thymus DNA and linked to deviations in intrinsic viscosity plots.
- The need to differentiate between secondary and tertiary structure contributions to DNA elongation was identified.
Purpose of the Study:
- To investigate the structural basis of DNA elongation in eukaryotic and prokaryotic species.
- To differentiate between secondary and tertiary structure contributions to DNA elongation effects.
- To explore the influence of temperature on DNA structural dynamics and elongation.
Main Methods:
- Viscometry titration technique to measure intrinsic viscosity.
- Analysis of DNA intrinsic viscosity as a function of sodium ion concentration (cs).
- Temperature-dependent measurements for eukaryotic and prokaryotic DNA species.
Main Results:
- Eukaryotic DNA showed a negative slope for elongation effects with increasing temperature, suggesting tertiary structure involvement.
- Prokaryotic DNA exhibited smaller, positive temperature slopes, indicating different elongation mechanisms.
- Abolition of tertiary structure components in eukaryotic DNA was proposed as the primary cause of elongation.
Conclusions:
- Eukaryotic DNA elongation is mainly driven by the electrostatic abolition of tertiary structures.
- Prokaryotic DNA elongation appears dominated by base breathing mechanisms.
- Temperature-dependent viscometry reveals distinct structural dynamics in eukaryotic versus prokaryotic DNA.