A calorimetric study of the different thermal behaviour of DNA in the isotropic and liquid-crystalline states

Grasso, Domenico; Fasone, Salvatore; Raudino, Antonio; Salyanov, V. I.

doi:10.1080/02678299108035507

Cited by 34 publications

(23 citation statements)

References 7 publications

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“…Curve 1 in Fig. 7 shows that the cholesteric DNA LCD is "melted" in a narrow temperature range (∼5 • C) and the τ m value of about 75 • C. The process of the "CD melting" of the DNA LCD particles reflects the change in the twist angle of their spatial structure; it does not accompanied by the dsDNA chains separation and, due to sterical reasons, the process of the "CD melting" of the DNA LCD is fully reversible [33,34]. The "melting" of NaCs occurs in the temperature range where the cholesteric structure of the LCD particles still persists.…”

Section: Temperature Dependence Of Optical Properties Of Nanoconstrucmentioning

confidence: 95%

Nanoconstructions based on double-stranded nucleic acids

Yevdokimov

Skuridin

Nechipurenko

et al. 2005

International Journal of Biological Macromolecules

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Section: Temperature Dependence Of Optical Properties Of Nanoconstrucmentioning

confidence: 95%

Nanoconstructions based on double-stranded nucleic acids

Yevdokimov

Skuridin

Nechipurenko

et al. 2005

International Journal of Biological Macromolecules

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“…The peculiarities of this process have been carefully investigated in a whole series of papers [20,21,43]. Despite the increase in temperature, the osmotic pressure of the PEG-containing solution [44,45] [46][47][48][49]. The disappearance of the abnormal band amplitude in the CD spectra of LCDs formed in domain I corresponds to the transition to a structure with a distorted location of the neighboring DNA molecules within the LCD particles.…”

Section: The Effect Of Temperature On the Optical Properties Of Ds Dnmentioning

confidence: 99%

Re-entrant cholesteric phase in DNA liquid-crystalline dispersion particles

et al. 2016

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In this research, we observe and rationalize theoretically the transition from hexagonal to cholesteric packing of double-stranded (ds) DNA in dispersion particles. The samples were obtained by phase exclusion of linear ds DNA molecules from water-salt solutions of poly(ethylene glycol)-PEG-with concentrations ranging from 120 mg ml −1 to 300 mg ml −1 . In the range of PEG concentrations from 120 mg ml −1 to 220 mg ml −1 at room temperature, we find ds DNA molecule packing, typical of classical cholesterics. The corresponding parameters for dispersion particles obtained at concentrations greater than 220 mg ml −1 indicate hexagonal packing of the ds DNA molecules. However, slightly counter-intuitively, the cholesteric-like packing reappears upon the heating of dispersions with hexagonal packing of ds DNA molecules. This transition occurs when the PEG concentration is larger than 220 mg ml −1 . The obtained new cholesteric structure differs from the classical cholesterics observed in the PEG concentration range 120-220 mg ml −1 (hence, the term 're-entrant'). Our conclusions are based on the measurements of circular dichroism spectra, X-ray scattering curves and textures of liquid-crystalline phases. We propose a qualitative (similar to the Lindemann criterion for melting of conventional crystals) explanation of this phenomenon in terms of partial melting of so-called quasinematic layers formed by the DNA molecules. The quasinematic layers change their spatial orientation as a result of the competition between the osmotic pressure of the

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“…Because separation of chains of the dsDNA molecules in the content of particles of the LCD is impossible due to the sterical reasons [31,32], the alteration of the dsDNA structure, induced by gadolinium treatment, is "transformed" into the change in the mode of spatial packing of the neighboring DNA molecules in these particles. Hence, the first reason is the change of the pitch of the cholesteric structure of the dsNA LCD as a result of interaction of gadolinium ions with these molecules.…”

Section: The CD Spectra Of the Cholesteric Lcd Of Nucleic Acids Treatmentioning

confidence: 99%