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Author Spotlight: Characterizing DNA Replication of Pathogenic Repeats to Uncover Mechanisms of Replication Fork Stalling and Expansion
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Observations of three "re-entrant" twisted structures in double-stranded DNA dispersion particles
Yuri M Yevdokimov1, Sergey G Skuridin2, Viktor I Salyanov1
1Engelhardt Institute of Molecular Biology of the Russian Academy of Sciences, Vavilova st. 32, Moscow, Russia, 119991.
European Biophysics Journal : EBJ
|November 28, 2021
Summary
Researchers observed novel twisted liquid-crystalline structures in DNA. Heating and cooling DNA dispersions, along with cation modification, induced unique "re-entrant" cholesteric structures, expanding our understanding of DNA self-assembly.
Area of Science:
- Biophysics
- Materials Science
- Supramolecular Chemistry
Background:
- Liquid-crystalline phases are formed by self-assembling molecules.
- DNA can exhibit liquid-crystalline properties under specific conditions.
- Understanding DNA's structural behavior is crucial for nanotechnology and biomaterials.
Purpose of the Study:
- To investigate the formation of novel twisted structures in DNA liquid-crystalline dispersions.
- To characterize the influence of temperature and ionic environment on DNA molecular organization.
- To explore the creation of new "re-entrant" cholesteric structures in DNA.
Main Methods:
- Preparation of double-stranded (ds) DNA dispersions in aqueous-salt solutions with poly(ethylene glycol).
- Thermal treatment (heating to 80°C and cooling to 22°C) of DNA dispersions.
- Modification of DNA dispersions by cation exchange (Na+ to Gd3+).
- Observation and characterization of liquid-crystalline structures using optical microscopy and other techniques.
Main Results:
- Formation of a new optically active, spirally twisted structure (rest-A) upon heating DNA dispersions.
- Appearance of an additional "re-entrant" cholesteric structure (rest-B) upon cooling.
- Induction of a third "re-entrant" cholesteric structure (rest-C) by replacing Na+ with Gd3+ cations, even at high DNA packing densities.
Conclusions:
- DNA liquid-crystalline dispersions can form multiple novel "re-entrant" cholesteric structures under varying thermal and ionic conditions.
- The observed structures demonstrate the adaptability of DNA's self-assembly capabilities.
- These findings offer new possibilities for designing DNA-based materials with tunable optical and structural properties.
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