Denaturing double-stranded DNA does not affect its viscosity
DOI: 10.1063/10.0000273
Denaturing double-stranded DNA does not affect its viscosity lead image
The fluid properties of DNA have become of particular interest in the study of genetic recombination and diseases such as cystic fibrosis. One theory relating elasticity to orientation of polymeric liquids, called general rigid bead-rod modelling, has shown promise for recreating such complex macromolecular architectures.
Piette et al. present an analysis of the complex viscosity of DNA molecules using general rigid bead-rod theory. By investigating the effects of helix radius, flight length, helix length and number of beads per flight on a variety of viscous and elastic properties of both single- and double-stranded structures, the group explored how DNA base pairs and helices contributed to the molecule’s complex viscosity.
The work marks the most complex macromolecular architecture to be studied with the theory to date.
“The challenges still facing the rheology area are the lack of theoretical methods that help us design polymers with specific properties,” said author Mona Kanso. “This work closes a part of this gap by conducting research that provides information on polymer architecture and its relation to viscoelastic properties.”
General rigid bead-rod theory recreates molecular structures by fixing beads relative to one another, which informs how orientation develops during flow.
Among their results, the group found that unzipping a double-stranded molecule of DNA into single strands has no effect on the viscosity of the solution. The group calls this phenomenon viscostasis.
“An interesting part of this work is the viscostatic unzipping DNA, a property that has not been mentioned or discovered in previous work,” said author Jourdain Piette. “Our paper uncovers stunning agreement with experimental measurement.”
Source: “Complex viscosity of helical and doubly helical polymeric liquids from general rigid bead-rod theory,” by J. H. Piette, A. J. Giacomin, and M. A. Kanso, Physics of Fluids (2019). The article can be accessed at https://doi.org/10.1063/1.5126860 .
