Mechanochemical study of wet‐spun lithium‐DNA fibers

Rupprecht, A.

doi:10.1002/bip.1970.360090708

Cited by 17 publications

(8 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…76 to obtain the fiber bundle laid out helically on the rotating cylinder. In the present work, 8 spinning sweeps and a spinneret with 720 holes (each 70 pm in diameter) were used so the bundle contained about 8 X 720 = 5760 DNA fibers.…”

Section: Materials a N D Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Mechanochemical study of conformational transitions and melting of Li‐, Na‐, K‐, and CsDNA fibers in ethanol–water solutions

et al. 1994

View full text Add to dashboard Cite

SYNOPSISHighly oriented fibers of Li-, Na-, K-, and CsDNA were prepared with a previously developed wet spinning method. The procedure gave a large number of equivalent fiber bundle samples (reference length, Lo, typically = 12-15 cm) for systematic measurements of the fiber length L in ethanol-water solutions, using a simple mechanochemical set up. The decrease in relative length L / Lo with increasing ethanol concentration at room temperature gave evidence for the B-A transition centered at 76% ( v / v ) ethanol for NaDNA fibers and at 80 and 84% ethanol for Kand CsDNA fibers. A smaller decrease in L / L o of LiDNA fibers was attributed to the B-C transition centered at 80% ethanol. In a second type of experiment with DNA fibers in ethanol-water solutions, the heat-induced helix-coil transition, or melting, revealed itself in a marked contraction of the DNA fibers. The melting temperature T,, decreased linearly with increasing ethanol concentration for fibers in the B-DNA ethanol concentration region. In the B-A transition region, Na-and KUNA fibers showed a local maximum in T,. On further increase of the ethanol concentration, the A-DNA region followed with an even steeper linear decrease in T,. The dependence on the identity of the counterion is discussed with reference to the model for groove binding of cations in B-DNA developed by Skuratovskii and co-workers and to the results from Raman studies of the interhelical bonds in A-DNA performed by Lindsay and co-workers. An attempt to apply the theory of Chogovadze and Frank-Kamenetskii on DNA melting in the B-A transition region to the curves failed. However, for Na-and KDNA the T , dependence in and around the A-B transition region could be expressed as a weighted mean value of T , of Aand B-DNA. On further increase of the ethanol concentration, above 84% ethanol for LiDNA and above about 90% ethanol for Na-, K-, and CsDNA, a drastic change occurred. T , increased and a few percentages higher ethanol concentrations were found to stabilize the DNA fibers so that they did not melt at all, not even at the upper temperature limit of the experiments ( -80°C). This is interpreted as being due to the strong aggregation induced by these high ethanol concentrations and to the formation of P-DNA. Many features of the results are compatible with the counterion-water affinity model. In another series of measurements, T,,, of DNA fibers in 75% ethanol was measured at various salt concentrations. No salt effect was observed (with the exception of LiDNA at low salt concentrations). This result is supported hy calculations within the Poisson-Roltzmann cylindrical cell model.

show abstract

Section: Materials a N D Methodsmentioning

confidence: 99%

“…These operations were performed in the respective spinning bath, by analogy with the procedure described in Ref. 76 from the spinning cylinder) the DNA fibers had relaxed (up t o about 1% contraction) and the equilibrium length Lo could be determined.…”

Section: Materials a N D Methodsmentioning

confidence: 99%

Mechanochemical study of conformational transitions and melting of Li‐, Na‐, K‐, and CsDNA fibers in ethanol–water solutions

et al. 1994

View full text Add to dashboard Cite

show abstract

“…This method was early modified for the preparation of a long fiber bundle of oriented DNA molecules from which a large number of reproducible samples could be taken for mechanochemical study [26]. Recently, a simple set-up was suggested for mechanochemical studies of conformational and helix-to-coil transitions in such DNA fiber samples [27,28,29,30].…”

Section: Use Of Highly Oriented Fibersmentioning

confidence: 99%

“…A wet spinning method has been used for over three decades for preparing samples of highly oriented DNA suitable for various physico-chemical studies [23,24,25]. This method was early modified for the preparation of a long fiber bundle of oriented DNA molecules from which a large number of reproducible samples could be taken for mechanochemical study [26]. Recently, a simple set-up was suggested for mechanochemical studies of conformational and helix-to-coil transitions in such DNA fiber samples [27,28,29,30] MgDNA is more stable against disaggregation; (ii) the minimal value of 7"' and (iii) the thermostable DNA structure are reached at much lower ethanol concentrations in the case of MgDNA.…”

Section: Use Of Highly Oriented Fibersmentioning

confidence: 99%

Aggregated DNA in ethanol solution

Piškur

Rupprecht

1995

FEBS Letters

View full text Add to dashboard Cite

A recently developed mecbanocbemical method has provided a new, efficient tool for studies on the thermal stability and structure of aggregated DNA in ethanol-water solutions. At low ethanol concentrations DNA is fully soluble and is in the B form. However, with increasing ethanol concentration the melting temperature of DNA, T,,,, decreases. At a critical ethanol concentration, dependent on the nature and concentration of the counterion, aggregation of the DNA molecules sets in. This is reflected in a marked increase in T,,, indicating that the aggregated DNA molecules are thermally more stable than the dissolved ones. However, they are still in the B form. In general, T,,, of aggregated DNA also decreases with further increasing ethanol concentration and is dependent on the nature of the counterion, but T,,, is not affected by the concentration of the counterion (excess salt) in the ethanol-water solution. When the ethanol concentration reaches the range of 7040% (v/v), the B-to-A conformational transition occurs in the case of Na-, K-and CsDNA. Above this transition point the A form is more stable than the B form due to the reduced water activity and to increased interhelical interactions. At very high ethanol concentrations, above 85% and dependent on the nature of the counterion, a drastic change in the thermal behaviour is observed. Apparently such a strong interhelical interaction is induced in the aggregated DNA that the DNA is stabilized and cannot adopt a random coil state even at very high temperatures. This stability of DNA in the P form is fully reversed if the ethanol concentration is lowered and the activity of water, thereby, is restored.

show abstract

“…This, in turn, is supported by birefringence measurements (Wilkins et al 1951) and X-ray diffraction data on elongated drying DNA fibres (Greenall et al 2001) which followed up early data by Wilkins suggesting an increase in the base pair spacing from 3.4 to about 5.6 Å in stretched oriented fibres (Wilkins 1961). These data are, however, not readily compared to the data from single molecules since mechanically stretched DNA fibres and films show plastic flow and lack (even at a high degree of orientation) the characteristic force plateau observed in single-molecule experiments (Rupprecht 1970).…”

Section: Introductionmentioning

confidence: 96%

Force-induced structural transitions in cross-linked DNA films

et al. 2008

View full text Add to dashboard Cite

We report on the preparation and characterization of wet-spun films of sodium DNA in which intermolecular cross-links were introduced following formaldehyde treatment. Raman scattering shows that the DNA in moderately cross-linked films is mainly in the B conformation. Stretching experiments show a transition from plastic to elastomeric behavior with increasing exposure to the cross-linking agent. Elastomeric DNA films are strongly disordered. X-ray diffraction shows that stretching of moderately cross-linked films under controlled high humidity conditions results in increased molecular orientation as well as the appearance of meridional reflections at 7.4-7.8 and 8.2 angstroms. These reflections are not observed for any of the classical conformations associated with mixed sequence DNA, and may arise from extended base-pair stacking in a stretched DNA structure.

show abstract

Mechanochemical study of wet‐spun lithium‐DNA fibers

Cited by 17 publications

References 39 publications

Mechanochemical study of conformational transitions and melting of Li‐, Na‐, K‐, and CsDNA fibers in ethanol–water solutions

Mechanochemical study of conformational transitions and melting of Li‐, Na‐, K‐, and CsDNA fibers in ethanol–water solutions

Aggregated DNA in ethanol solution

Force-induced structural transitions in cross-linked DNA films

Contact Info

Product

Resources

About