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DNA-cationic surfactant interactions are different for double- and single-stranded DNA

Rosa, Monica LU ; Dias, Rita LU ; Miguel, Maria LU and Lindman, Björn LU (2005) In Biomacromolecules 6(4). p.2164-2171
Abstract
The stability of DNA in solution and the phase behavior in mixtures with dodecyltrimethylammonium bromide (DTAB) were investigated. By means of circular dichroism, UV absorption, and differential scanning calorimetry, we found that for dilute solutions of DNA with no addition of salt the DNA molecules are in the single-stranded conformation, whereas the addition of a small amount of NaBr, 1 mM, is sufficient to stabilize the DNA double-helix. Furthermore, at higher DNA concentrations, native DNA becomes the most stable structure, which is due to a self-screening effect. By phase diagram determinations of the DNA-surfactant system, we found that the effect of salt on phase behavior mainly relates to a difference in interaction of the... (More)
The stability of DNA in solution and the phase behavior in mixtures with dodecyltrimethylammonium bromide (DTAB) were investigated. By means of circular dichroism, UV absorption, and differential scanning calorimetry, we found that for dilute solutions of DNA with no addition of salt the DNA molecules are in the single-stranded conformation, whereas the addition of a small amount of NaBr, 1 mM, is sufficient to stabilize the DNA double-helix. Furthermore, at higher DNA concentrations, native DNA becomes the most stable structure, which is due to a self-screening effect. By phase diagram determinations of the DNA-surfactant system, we found that the effect of salt on phase behavior mainly relates to a difference in interaction of the amphiphile between single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). The difference in association between ss and dsDNA with surfactants of different chain lengths can be interpreted in terms of an interplay between hydrophobic and electrostatic interactions, the latter being influenced by polymer flexibility. In this way, a nonmonotonic variation can be rationalized. A crossing of the phase separation lines with DNA concentration can be rationalized in terms of a change in relative stability of ss and dsDNA. The fact that ssDNA phase separates earlier than dsDNA in association with DTAB, may serve as a basis for a method of easily separating dsDNA from ssDNA by the addition of surfactant; this is verified as monitored by circular dichroism measurements. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biomacromolecules
volume
6
issue
4
pages
2164 - 2171
publisher
The American Chemical Society
external identifiers
  • wos:000230498400047
  • scopus:22944468813
ISSN
1526-4602
DOI
10.1021/bm050137n
language
English
LU publication?
yes
id
3539f890-c179-4fc9-899d-6b5d498649b4 (old id 157559)
date added to LUP
2007-07-12 10:47:34
date last changed
2017-10-01 03:42:57
@article{3539f890-c179-4fc9-899d-6b5d498649b4,
  abstract     = {The stability of DNA in solution and the phase behavior in mixtures with dodecyltrimethylammonium bromide (DTAB) were investigated. By means of circular dichroism, UV absorption, and differential scanning calorimetry, we found that for dilute solutions of DNA with no addition of salt the DNA molecules are in the single-stranded conformation, whereas the addition of a small amount of NaBr, 1 mM, is sufficient to stabilize the DNA double-helix. Furthermore, at higher DNA concentrations, native DNA becomes the most stable structure, which is due to a self-screening effect. By phase diagram determinations of the DNA-surfactant system, we found that the effect of salt on phase behavior mainly relates to a difference in interaction of the amphiphile between single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). The difference in association between ss and dsDNA with surfactants of different chain lengths can be interpreted in terms of an interplay between hydrophobic and electrostatic interactions, the latter being influenced by polymer flexibility. In this way, a nonmonotonic variation can be rationalized. A crossing of the phase separation lines with DNA concentration can be rationalized in terms of a change in relative stability of ss and dsDNA. The fact that ssDNA phase separates earlier than dsDNA in association with DTAB, may serve as a basis for a method of easily separating dsDNA from ssDNA by the addition of surfactant; this is verified as monitored by circular dichroism measurements.},
  author       = {Rosa, Monica and Dias, Rita and Miguel, Maria and Lindman, Björn},
  issn         = {1526-4602},
  language     = {eng},
  number       = {4},
  pages        = {2164--2171},
  publisher    = {The American Chemical Society},
  series       = {Biomacromolecules},
  title        = {DNA-cationic surfactant interactions are different for double- and single-stranded DNA},
  url          = {http://dx.doi.org/10.1021/bm050137n},
  volume       = {6},
  year         = {2005},
}