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Local and translational dynamics in DNA-lipid assemblies monitored by solid-state and diffusion NMR.

Leal, Cecilia LU ; Sandström, Dick; Nevsten, Pernilla LU and Topgaard, Daniel LU (2008) In Biochimica et Biophysica Acta - Biomembranes 1778(1). p.214-228
Abstract
The influence of electrostatic interactions on the dynamic properties of complexes containing DNA and mixtures of cationic- (DDA) and zwitterionic (DLPC) lipids are studied by means of NMR. The systems are arranged in lamellar membrane stacks intercalated by DNA molecules. This is confirmed by 31P-NMR, where a superposition of an axially symmetric powder pattern arising from the phospholipid membrane and an asymmetric tensor due to DNA can be fitted to the experimentally observed lineshape. The local mobility and order is assessed using two solid-state NMR techniques applicable to samples with natural isotopic abundance: WIdeline SEparation (WISE) and Separated Local Field (SLF) spectroscopy. Both experiments yield highly resolved 13C... (More)
The influence of electrostatic interactions on the dynamic properties of complexes containing DNA and mixtures of cationic- (DDA) and zwitterionic (DLPC) lipids are studied by means of NMR. The systems are arranged in lamellar membrane stacks intercalated by DNA molecules. This is confirmed by 31P-NMR, where a superposition of an axially symmetric powder pattern arising from the phospholipid membrane and an asymmetric tensor due to DNA can be fitted to the experimentally observed lineshape. The local mobility and order is assessed using two solid-state NMR techniques applicable to samples with natural isotopic abundance: WIdeline SEparation (WISE) and Separated Local Field (SLF) spectroscopy. Both experiments yield highly resolved 13C spectra in the direct dimension. The indirect dimension contains information about molecular dynamics through the 1H dipolar linewidth (WISE) or the 1H(-13)C dipolar coupling constant (SLF). The experiments suggest that DNA is static while it induces an increased disorder in the hydrocarbon chains as compared to the parent lipid case. DDA chain order is more affected than DLPC due to the attractive electrostatic interaction between DNA and the cationic lipid. Translational dynamics of the lipids and the water was measured with the Pulsed Field Gradient STimulated Echo (PFG STE) technique. The influence of lamellar domain size and the angular dependence of the diffusion coefficients and nuclear relaxation times on the results of the PFG STE experiments are discussed. The local water diffusion coefficient is reduced by a factor four from the value of bulk water, and increases as the DLPC content is increased. We observe two lipid components with an order of magnitude difference in diffusion coefficients in the DNA:DDA:DLPC precipitate and these are assigned to DLPC (fast) and DDA (slow). Cationic lipid (DDA) diffusion is decreasing a factor of 2 when DLPC is added to the pure DNA:DDA system, indicating DNA-induced lipid segregation within the bilayer and the transition from locally 2D to 1D diffusion of the DDA. The results show that DNA-lipid electrostatic interactions reduce the long-range lipid mobility but locally enhance the hydrocarbon chain dynamics by perturbing the preferred lipid packing. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Lipids: chemistry, DNA: chemistry, DNA: ultrastructure
in
Biochimica et Biophysica Acta - Biomembranes
volume
1778
issue
1
pages
214 - 228
publisher
Elsevier
external identifiers
  • pmid:18320639
  • wos:000253269500023
  • scopus:38149061095
ISSN
0005-2736
DOI
10.1016/j.bbamem.2007.09.035
language
English
LU publication?
yes
id
fefa5f0b-6200-47a2-9b2c-cfb0c4fee065 (old id 1052779)
date added to LUP
2008-04-28 21:05:12
date last changed
2017-08-27 05:03:25
@article{fefa5f0b-6200-47a2-9b2c-cfb0c4fee065,
  abstract     = {The influence of electrostatic interactions on the dynamic properties of complexes containing DNA and mixtures of cationic- (DDA) and zwitterionic (DLPC) lipids are studied by means of NMR. The systems are arranged in lamellar membrane stacks intercalated by DNA molecules. This is confirmed by 31P-NMR, where a superposition of an axially symmetric powder pattern arising from the phospholipid membrane and an asymmetric tensor due to DNA can be fitted to the experimentally observed lineshape. The local mobility and order is assessed using two solid-state NMR techniques applicable to samples with natural isotopic abundance: WIdeline SEparation (WISE) and Separated Local Field (SLF) spectroscopy. Both experiments yield highly resolved 13C spectra in the direct dimension. The indirect dimension contains information about molecular dynamics through the 1H dipolar linewidth (WISE) or the 1H(-13)C dipolar coupling constant (SLF). The experiments suggest that DNA is static while it induces an increased disorder in the hydrocarbon chains as compared to the parent lipid case. DDA chain order is more affected than DLPC due to the attractive electrostatic interaction between DNA and the cationic lipid. Translational dynamics of the lipids and the water was measured with the Pulsed Field Gradient STimulated Echo (PFG STE) technique. The influence of lamellar domain size and the angular dependence of the diffusion coefficients and nuclear relaxation times on the results of the PFG STE experiments are discussed. The local water diffusion coefficient is reduced by a factor four from the value of bulk water, and increases as the DLPC content is increased. We observe two lipid components with an order of magnitude difference in diffusion coefficients in the DNA:DDA:DLPC precipitate and these are assigned to DLPC (fast) and DDA (slow). Cationic lipid (DDA) diffusion is decreasing a factor of 2 when DLPC is added to the pure DNA:DDA system, indicating DNA-induced lipid segregation within the bilayer and the transition from locally 2D to 1D diffusion of the DDA. The results show that DNA-lipid electrostatic interactions reduce the long-range lipid mobility but locally enhance the hydrocarbon chain dynamics by perturbing the preferred lipid packing.},
  author       = {Leal, Cecilia and Sandström, Dick and Nevsten, Pernilla and Topgaard, Daniel},
  issn         = {0005-2736},
  keyword      = {Lipids: chemistry,DNA: chemistry,DNA: ultrastructure},
  language     = {eng},
  number       = {1},
  pages        = {214--228},
  publisher    = {Elsevier},
  series       = {Biochimica et Biophysica Acta - Biomembranes},
  title        = {Local and translational dynamics in DNA-lipid assemblies monitored by solid-state and diffusion NMR.},
  url          = {http://dx.doi.org/10.1016/j.bbamem.2007.09.035},
  volume       = {1778},
  year         = {2008},
}