NMR Studies of Molecular Mobility in a DNA−Amphiphile Complex

Leal, Cecı́lia; Topgaard, Daniel; Martin, Rachel W.; Wennerström, Håkan

doi:10.1021/jp0480495

Cited by 17 publications

(23 citation statements)

References 29 publications

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“…We have used a value of 1.72 Å per DNA base and taking into account the hydrophobic length of the surfactants to form cylinders. For the surfactants, the used length and volume values are summarized in Table 5 together with the theoretically calculated surfactant/base molar ratio for the different DNA helices/surfactant arrangements For CTAB-DNA and MTAB-DNA complexes the experimental Surfactant/Base molar ratios are 1.47 and 1.78 respectively, close to those expected for a 3:1 arrangement, which agrees with previous results 39,40 .…”

Section: Gisaxs Studiessupporting

confidence: 87%

“…This is due to the longer and flexible nature of the head group, which allows for reducing the repulsive interactions from neighboring DNA helices in a more effective way. In the case of CTAB, a distortion/expansion of the cationic surfactant cylinder is needed to increase the surfactant-DNA interaction, and this should also result in an increase of conformational disorder of the alkyl chains 40 .…”

Section: Gisaxs Studiesmentioning

confidence: 99%

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The nanostructure of surfactant–DNA complexes with different arrangements

Mezei

Morán

2013

Colloids and Surfaces B: Biointerfaces

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The nanostructure of DNA with different cationic surfactant has been studied in order to elucidate the detailed arrangement concerning the position of DNA and surfactant domains in the complexes. Also, the orientation of the DNA cylinders in the thin films of the complexes was investigated. Attention was directed on the preparation methods of the complexes and to how the different surfactant structure affects the compaction of the DNA. The cationic surfactant-DNA complexes were investigated by X-ray scattering, polarized light microscopy and elemental microanalysis. It was observed that the molecular organization of the complexes between DNA and cationic surfactant corresponds to a hexagonal structure with different packing arrangements. The nanostructure of the complexes depends on the hydrophobic/hydrophilic balance of the cationic surfactant. In particular the use of arginine derived surfactants, with a large polar head group able to interact not only by electrostatics but also by hydrogen bonding, allows for the formation of more compact structures. The results suggest that the smaller the lattice parameter the more compact and stable is the complex implying slower DNA release.

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Section: Gisaxs Studiessupporting

confidence: 87%

Section: Gisaxs Studiesmentioning

confidence: 99%

The nanostructure of surfactant–DNA complexes with different arrangements

Mezei

Morán

2013

Colloids and Surfaces B: Biointerfaces

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“…There are no clear effects on the lipid acyl chains deeper inside the bilayer, which would be expected if the protein were penetrating deeper into the membrane. Here we notice structural similarities to the systems composed of -helical DNA compacted in an oppositely charged lipid or surfactant self-assembled systems (42)(43)(44), which leads to a reduction in lipid molecular dynamics (40,45).…”

Section: Dehydrin-lipid Association: Effects On Lipid Molecular Dynamicsmentioning

confidence: 68%

The plant dehydrin Lti30 stabilizes lipid lamellar structures in varying hydration conditions

Andersson

Pham

Mateos

et al. 2020

Journal of Lipid Research

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A major challenge to plant growth and survival are changes in temperature and diminishing water supply. During acute temperature and water stress, plants often express stress proteins, such as dehydrins, which are intrinsically disordered hydrophilic proteins. In this article, we investigated how the dehydrin Lti30 from Arabidopsis thaliana stabilizes membrane systems that are exposed to large changes in hydration. We also compared the effects of Lti30 on membranes with those of the simple osmolytes urea and trimethylamine N-oxide. Using X-ray diffraction and solid-state NMR, we studied lipid-protein self-assembly at varying hydration levels. We made the following observations: 1) the association of Lti30 with anionic membranes relies on electrostatic attraction, and the protein is located in the bilayer interfacial membrane region; 2) Lti30 can stabilize the lamellar multilayer structure, making it insensitive to variations in water content; 3) in lipid systems with a composition similar to those present in some seeds and plants, dehydrin can prevent the formation of nonlamellar phases upon drying, which may be crucial for maintaining membrane integrity; and 4) Lti30 stabilizes bilayer structures both at high and low water contents, whereas the small osmolyte molecules mainly prevent dehydration-induced transitions. These results corroborate the idea that dehydrins are part of a sensitive and multifaceted regulatory mechanism that protects plant cells against stress.

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“…In the wide-angle region, no peak was detected. We performed 1 H NMR on dry and wet DNACTA precipitates, 37 and for the fully hydrated complex, several narrow peaks were observed, whereas for the dry complex there was one rather broad peak. The spectrum for the wet complex is similar to the one observed for CTAB rodlike micelles arranged in an hexagonal structure.…”

Section: Discussionmentioning

confidence: 99%

The Hydration of a DNA−Amphiphile Complex

et al. 2004

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We present measurements of isothermal DNA-hexadecyltrimethylammonium (DNACTA) complex and pure DNA hydration at 25°C using a sorption microcalorimeter. This calorimeter provides simultaneous measurement of (i) water activity (sorption isotherms) and (ii) the partial molar enthalpy of water as a function of water uptake. For pure DNA, hydration is exothermic over the studied concentration range and we find an approximately linear relation between the partial molar enthalpy and the partial molar free energy. A kink in the isotherm appears at 20.0 ( 0.3 water molecules per base pair for a water activity of 0.80, consistent with A-B transition of the DNA. There is no detectable heat effect associated with this transition. At low water contents, the hydration of the DNACTA (1:1) complex is exothermic as for the pure DNA, but after incorporation of the first 7.0 ( 0.1 water molecules, the enthalpy changes sign. At 22 water molecules per base pair, the enthalpy levels off to 2.7 ( 0.2 kJ/mol. In a separate experiment, the swelling limit for the DNACTA complex was found to be 27 ( 1 waters per base pair. The DNACTA complex is arranged in a hexagonal structure. We propose a model for the DNACTA complex based on the packing of the components in an electroneutral way consisting of six DNA helices, presumably in an A configuration, placed around a central CTA + cylinder. The hydration of the complex is seen as a balance between the attractive electrostatic interaction causing the formation of the complex and a repulsive component arising from a hexagonal deformation of CTA + cylinders. An important contribution to the partial molar enthalpy of water comes, in this interpretation, from the release of conformational constraints of the CTA ion alkyl chains.

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NMR Studies of Molecular Mobility in a DNA−Amphiphile Complex

Cited by 17 publications

References 29 publications

The nanostructure of surfactant–DNA complexes with different arrangements

The nanostructure of surfactant–DNA complexes with different arrangements

The plant dehydrin Lti30 stabilizes lipid lamellar structures in varying hydration conditions

The Hydration of a DNA−Amphiphile Complex

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