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Electrophoretic properties of complexes between DNA and the cationic surfactant cetyltrimethylammonium bromide

Dias, Rita LU ; Svingen, R; Gustavsson, B; Lindman, Björn LU ; Miguel, Maria LU and Åkerman, B (2005) In Electrophoresis 26(15). p.2908-2917
Abstract
We use agarose gel electrophoresis to characterize how the monovalent catioinic surfactant cetyltrimethylammonium bromide (CTAB) compacts double-stranded DNA, which is detected as a reduction in electrophoretic DNA velocity. The velocity reaches a plateau at a ratio R = 1.8 of CTAB to DNA-phosphate charges, i.e., above the neutralization point, and the complexes retain a net negative charge at least up to R = 200. Condensation experiments on a mixture of two DNA sizes show that the complexes formed contain only one condensed DNA molecule each. These CTAB-DNA globules were further characterized by time-resolved measurements of their velocity inside the gel, which showed that CTAB does not dissociate during the migration but possibly upon... (More)
We use agarose gel electrophoresis to characterize how the monovalent catioinic surfactant cetyltrimethylammonium bromide (CTAB) compacts double-stranded DNA, which is detected as a reduction in electrophoretic DNA velocity. The velocity reaches a plateau at a ratio R = 1.8 of CTAB to DNA-phosphate charges, i.e., above the neutralization point, and the complexes retain a net negative charge at least up to R = 200. Condensation experiments on a mixture of two DNA sizes show that the complexes formed contain only one condensed DNA molecule each. These CTAB-DNA globules were further characterized by time-resolved measurements of their velocity inside the gel, which showed that CTAB does not dissociate during the migration but possibly upon entry into the gel. Using the Ogston-model for electrophoresis of spherical particles, the measured in-gel velocity of the globule is quantitatively consistent with CTAB having two opposite effects, reduction of both the electrophoretic charge and DNA coil size. In the case of CTAB the two effects nearly cancel, which can explain why opposite velocity shifts (globule faster than uncomplexed DNA) have been observed with some catioinic condensation agents. Dissociation of the complexes by addition of anionic surfactants was also studied. The DNA release from the globule was complete at a mixing ratio between anionic and cationic surfactants equal to 1, in agreement with equilibrium studies. Circular DNA retained its supercoiling, and this demonstrates a lack of DNA nicking in the compaction-release cycle which is important in DNA transfection and purification applications. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Electrophoresis
volume
26
issue
15
pages
2908 - 2917
publisher
John Wiley & Sons
external identifiers
  • scopus:23844451859
ISSN
0173-0835
DOI
10.1002/elps.200400182
language
English
LU publication?
yes
id
2a599c3c-488a-4beb-b042-cc9860bbf7d3 (old id 157332)
date added to LUP
2007-07-11 10:33:35
date last changed
2017-01-01 04:35:11
@article{2a599c3c-488a-4beb-b042-cc9860bbf7d3,
  abstract     = {We use agarose gel electrophoresis to characterize how the monovalent catioinic surfactant cetyltrimethylammonium bromide (CTAB) compacts double-stranded DNA, which is detected as a reduction in electrophoretic DNA velocity. The velocity reaches a plateau at a ratio R = 1.8 of CTAB to DNA-phosphate charges, i.e., above the neutralization point, and the complexes retain a net negative charge at least up to R = 200. Condensation experiments on a mixture of two DNA sizes show that the complexes formed contain only one condensed DNA molecule each. These CTAB-DNA globules were further characterized by time-resolved measurements of their velocity inside the gel, which showed that CTAB does not dissociate during the migration but possibly upon entry into the gel. Using the Ogston-model for electrophoresis of spherical particles, the measured in-gel velocity of the globule is quantitatively consistent with CTAB having two opposite effects, reduction of both the electrophoretic charge and DNA coil size. In the case of CTAB the two effects nearly cancel, which can explain why opposite velocity shifts (globule faster than uncomplexed DNA) have been observed with some catioinic condensation agents. Dissociation of the complexes by addition of anionic surfactants was also studied. The DNA release from the globule was complete at a mixing ratio between anionic and cationic surfactants equal to 1, in agreement with equilibrium studies. Circular DNA retained its supercoiling, and this demonstrates a lack of DNA nicking in the compaction-release cycle which is important in DNA transfection and purification applications.},
  author       = {Dias, Rita and Svingen, R and Gustavsson, B and Lindman, Björn and Miguel, Maria and Åkerman, B},
  issn         = {0173-0835},
  language     = {eng},
  number       = {15},
  pages        = {2908--2917},
  publisher    = {John Wiley & Sons},
  series       = {Electrophoresis},
  title        = {Electrophoretic properties of complexes between DNA and the cationic surfactant cetyltrimethylammonium bromide},
  url          = {http://dx.doi.org/10.1002/elps.200400182},
  volume       = {26},
  year         = {2005},
}