scholarly journals Subpicosecond dynamics in calf-thymus DNA, in the presence of Zn2+ions: A Raman spectroscopic study

2009 ◽  
Vol 23 (3-4) ◽  
pp. 141-154 ◽  
Author(s):  
Cristina M. Muntean ◽  
Ioan Bratu ◽  
Konstantinos Nalpantidis ◽  
Monica A. P. Purcaru

In this paper the Raman total half bandwidths of calf-thymus DNA vibrations have been measured as a function of Zn2+ions concentration, in the presence of a constant concentration of Na+ions, respectively. The dependencies of the total half bandwidths and of the global relaxation times, on DNA molecular subgroup structure and on Zn2+ions concentration, are reported. It is shown that changes in the subpicosecond dynamics of molecular subgroups in ZnDNA complexes can be monitored with Raman spectroscopy.Particularly, the Raman band parameters for the vibrations at 729 cm−1(dA), 792 cm−1(dC, dT and 5'-C–O–P–O–C-3' network), 1094 cm−1(DNA backbone PO2−symmetric stretching), 1377 cm−1(dA, dT, dC), 1489 cm−1(the guanine N-7 and adenine rings) and 1581 cm−1(dG, dA) of ZnDNA complexes, in the presence of Zn2+ions concentrations that varied between 0 and 250 mM, are presented. In our study, the full widths at half-maximum (FWHM) of the bands in calf-thymus DNA complexes are typically in the wavenumber range from 10 to 50 cm−1. It can be observed that the molecular relaxation processes studied in this work, have a global relaxation time smaller than 0.94 ps and larger than 0.21 ps. The limit values are characterizing the dA and dG residues, respectively (vibrations at 729 cm−1and 1489 cm−1).Binding of Zn2+ions to double helical calf-thymus DNA results for some vibrations in smaller global relaxation times and larger bandwidths, respectively, possible as a consequence of the increased interaction of the base moieties with the solvent molecules in unstacked structures.The fastest and the slowest dynamics for different DNA structural subgroups and different Zn2+ions concentrations, respectively, have been analyzed.A comparison between different time scales of the vibrational energy transfer processes, characterizing the ZnDNA structural subgroups has been given.We have found that metal ion's type and concentration are modulators for the (sub)picosecond dynamics of calf thymus DNA molecular subgroups.

2008 ◽  
Vol 22 (6) ◽  
pp. 475-489 ◽  
Author(s):  
Cristina M. Muntean ◽  
Ioan Bratu

In this paper the Raman total half bandwidths of calf-thymus DNA vibrations have been measured as a function of pH (3.45–6.4), in the presence of Mn2+ions, respectively. The dependencies of the half bandwidths and of the global relaxation times, on DNA molecular subgroup structure and on pH, are reported. It is shown that changes in the subpicosecond dynamics of molecular subgroups in calf-thymus DNA can be monitored with Raman spectroscopy.Particularly, the Raman band parameters for the vibrations at 728 cm–1(dA), 787 cm–1(dC), 1093 cm–1(PO2–), 1376 cm–1(dA, dG, dT, dC), 1489 cm–1(dG, dA) and 1578 cm–1(dG, dA) of MnDNA complexes, at reduced and low pH values, are presented. In our study, the full widths at half-maximum (FWHM) of the bands in calf-thymus DNA are typically in the wavenumber range from 11 to 27 cm–1. It can be observed that the molecular relaxation processes studied in this work, have a global relaxation time smaller than 0.965 ps and larger than 0.393 ps. The limit values are characteristic for dA and dC residues, respectively (vibrations at 728 and 787 cm–1).Low pH-induced melting of double helical structure in calf-thymus DNA, in the presence of Mn2+ions, results for some bands in smaller global relaxation times, and larger bandwidths, respectively, as a consequence of the increased interaction of the base moieties with the solvent molecules. This behaviour is most evident for the bands at 787 cm–1up to pH 3.8, at 1578 cm–1up to pH 3.45 and is partially confirmed for the DNA backbone PO2–symmetric stretching vibration at 1093 cm–1.The fastest molecular dynamics was obtained for the adenine band at 728 cm–1in the pH interval 3.45–3.8 (global relaxation time 0.885 ps), for the cytosine ring breathing mode near 787 cm–1around the pH 3.8 (global relaxation time 0.393 ps), for the band at 1093 cm–1in the pH interval 3.8–4.4 (global relaxation time 0.518 ps) and for the vibration near 1578 cm–1at pH 3.45 (global relaxation time 0.544 ps).A comparison between different time scales of the vibrational energy transfer processes, characterizing the protonated MnDNA structural subgroups has been given.We have found that metal ion's type and concentration are modulators for the (sub)picosecond dynamics of protonated DNA molecular subgroups.


2007 ◽  
Vol 21 (4) ◽  
pp. 193-204 ◽  
Author(s):  
Cristina M. Muntean ◽  
Ioan Bratu

In this paper the Raman total half bandwidths of calf-thymus DNA vibrations have been measured as a function of pH, monovalent and divalent cations' type and concentration. The dependence of different band parameters on DNA molecular subgroup structure, on pH and on Na+, Ca2+and Mg2+ions concentrations, respectively, are reported. It is shown that changes in (sub)picosecond dynamics of molecular subgroups in calf-thymus DNA can be monitored with confocal Raman microspectroscopy.The half bandwidths and the global relaxation times for the vibrations at 728 cm−1(dA), 785 cm−1(dC), 1094 cm−1(PO2−), 1377 cm−1(dA, dG, dT, dC), 1488 cm−1(dG, dA) and 1580 cm−1(dG, dA) of calf-thymus DNA are presented. The full-widths at half-height (FWHH) of the bands in calf-thymus DNA are typically in the wavenumber range from 7.4 to 31 cm−1. The bandwidths in the Raman spectra are sensitive to a dynamics active on a time scale from 0.34 to 1.44 ps.Low pH-induced melting of double helical structure in calf-thymus DNA results for some bands in shorter global relaxation times, as a consequence of the increased interaction of the base moieties with the solvent molecules.The molecular dynamics characterizing the 785, 1094, 1377 and 1580 cm−1vibrations, is faster in the case of high divalent cations DNA sample (pH 7), as compared to the respective low divalent cations DNA sample (pH 7), for both Ca2+and Mg2+ions. The vibrational energy transfer process of the guanine band at 1488 cm−1is slower for the high salt DNA sample, pH 7 as compared to the corresponding low salt DNA sample, pH 7, for both Ca2+and Mg2+. Molecular dynamics characterizing the vibration at 1488 cm−1is faster for DNA sample at high Na+ions (pH 7), as compared to the DNA sample at low Na+ions (pH 7).As far as the CaDNA and MgDNA complexes are concerned (pH 7), the global relaxation times of some base vibrations decrease for the case of magnesium ions, as compared to the case of the same concentration of calcium ions. The different ionic radius of the two types of metal cations (0.72 Å for Mg and 0.99 Å for Ca) were considered in explaining these results.Molecular relaxation processes of DNA subgroups, upon lowering the pH, in the presence of Na+, Ca2+and Mg2+ions are presented. Particularly, at low Ca2+concentration, upon lowering the pH, the molecular dynamics of DNA subgroups corresponding to vibrations at 728, 1376, 1488 and 1580 cm−1is much faster, probably due to the denaturation process of the double helical DNA.


2008 ◽  
Vol 22 (5) ◽  
pp. 345-359 ◽  
Author(s):  
Cristina M. Muntean ◽  
Ioan Bratu

In this paper the Raman total half bandwidths of calf-thymus DNA vibrations have been measured as a function of Mn2+ion concentration (0–600 mM), in the presence of two concentrations of Na+cations, respectively. The dependencies of the half bandwidths and of the global relaxation times on DNA molecular subgroup structure, on Mn2+and Na+ions concentrations, respectively, are reported. It is shown that changes in the (sub)picosecond dynamics of molecular subgroups in calf-thymus DNA can be monitored with Raman spectroscopy.In this study the Raman band parameters for the vibrations at 729 cm-1(dA), 787 cm-1(dC), 1094 cm-1(PO2-), 1376 cm-1(dA, dG, dT, dC), 1489 cm-1(dG, dA) and 1578 cm-1(dG, dA) of calf thymus DNA are presented. The full-widths at half-height (FWHH) of the bands in calf-thymus DNA are typically in the wavenumber range from 9 to 33.5 cm-1. It can be observed that the molecular relaxation processes studied in this work, have a global relaxation time smaller than 1.179 ps and larger than 0.317 ps.Mn2+-induced DNA structural changes result for the vibrations at 729 cm-1and 787 cm-1in smaller global relaxation times, and larger half bandwidths, respectively, as compared to the starting value of 0 mM Mn2+. The vibrational energy transfer processes of these two subgroups (dA, dC), respectively, are slower in the case of DNA samples at 10 mM NaCl, as compared to the corresponding DNA samples at 150 mM NaCl. However, the behaviour of the global relaxation times characteristic to the bands at 729 and 787 cm-1is similar with respect to manganese(II) ions concentration, in the case of the two values of Na+ions content, respectively.On the contrary, the molecular dynamics is slower for the base vibrations at 1376, 1489 and 1578 cm-1, in the case of DNA samples at 150 mM NaCl, as compared to the corresponding samples at lower Na+concentration, in almost all Mn2+ions concentration range. The molecular relaxation processes in these three cases, respectively, are quite different for the corresponding samples with different Na+ions content, upon increasing divalent manganese ions concentration.The molecular dynamics characterizing the band near 1094 cm-1of the DNA backbone PO2-symmetric stretching vibration is faster upon increasing the Mn2+ions concentration between 0–600 mM and seems not to be influenced by the Na+ions content, specific to our experimental conditions.


2009 ◽  
Vol 23 (5-6) ◽  
pp. 281-289 ◽  
Author(s):  
Cristina M. Muntean ◽  
Ioan Bratu

In this paper the Raman total half bandwidths of eight genomic DNAs from leaf tissues [potato (Solanum tuberosumL.), sword fern (Nephrolepis exaltataL.), scopolia (Scopolia carniolicaJacq.), redwood (Sequoia sempervirensD. Don. Endl.), orchids (Cymbidium × hybrida), chrysanthemum (Dendranthema grandifloraRamat.) and common sundew (Drosera rotundifoliaL.)] have been measured. The dependencies of the total half bandwidths and of the global relaxation times, on DNA molecular subgroup structure and on the type of genomic plant DNA, are reported. It is shown that changes in the (sub)picosecond dynamics of molecular subgroups in genomic DNAs from leaf tissues can be monitored with Raman spectroscopy.Particularly, the Raman band parameters for the vibrations at 879 cm−1(deoxyribose, dA), 1047 cm−1(CO stretching C‒O‒P‒O‒C, dG), 1089 cm−1(P—O symmetric stretching of PO2‒), 1124 cm−1(dA), 1272 cm−1(dC, dG, dT), 1276 cm−1(dC), 1455 cm−1(deoxyribose, dA, dC, dT) and 1482 cm−1(dG, dA) of genomic leaf tissues DNAs are presented. In our study, the full widths at half-maximum (FWHM) of the bands in genomic DNAs from leaf tissues are typically in the wavenumber range from 7.8 to 23.1 cm−1. It can be observed that the molecular relaxation processes studied in this work, have a global relaxation time smaller than 1.36 ps and larger than 0.46 ps.The fastest and the slowest relaxation processes of different DNA structural subgroups, for several types of genomic DNA extracted from leaf tissue, have been analyzed. Particularly, the slowest dynamics corresponding to the vibration near 1272 cm−1takes place in the case of DNA extracted from common sundew (global relaxation time 1.36 ps).A comparison between different time scales of the vibrational energy transfer processes, characterizing several DNA complexes, has been given.We have found that the bands at 879 cm−1(deoxyribose, phosphodiester, dA) and 1455 cm−1(deoxyribose, dA, dC, dT) are suitable for the study of dynamical behavior of molecular subgroups in genomic DNA extracted from leaf tissues.Specific molecular relaxation processes, depending on the type of genomic DNA extracted from leaf tissues has been observed.


2011 ◽  
Vol 26 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Cristina M. Muntean ◽  
Ioan Bratu ◽  
Nicolae Leopold ◽  
Monica A. P. Purcaru

In this work the SERS total half bandwidths of five genomic DNAs fromin vitro-grown apple leaf tissues (Malus domesticaBorkh., FamRosaceae, cvs. Florina, Rebra, Goldrush, Romus 3 and Romus 4) have been measured. We have shown that surface-enhanced Raman scattering can be used to study the fast subpicosecond dynamics of DNA in the proximity of a metallic surface. The dependencies of the total half bandwidths and of the global relaxation times, on DNA molecular subgroup structure, on the type of genomic apple plant DNA and on time, are reported. An example of the time-dependence of SERS band parameters of DNA, in the proximity of silver nanoparticles, has been given. It is shown that changes in the subpicosecond surface dynamics of molecular subgroups in genomic DNAs fromin vitro-grown apple leaf tissues can be monitored with surface-enhanced Raman spectroscopy. Particularly, the SERS band parameters for the vibrations near 757 cm–1(dT), 773 cm–1(dC), 929 cm–1(deoxyribose), 1087 cm–1(PO2–symmetric stretch, backbone), 1127 cm–1(dA), 1181 cm–1(ring vibrations of dG, dT, dC), 1311 cm–1(dA), 1362 cm–1(dT, dA), 1510 cm–1(dA), 1573 cm–1(dG, dA) and 1650 cm–1[dT(C═O), δ(H2O)] of genomic DNAs from apple leaves are presented. In our study, the full widths at half-maximum (FWHM) of the bands in genomic DNAs fromin vitro-grown apple leaf tissues are typically in the wavenumber range from 14 to 52 cm–1. Besides, it can be observed that molecular relaxation processes studied in this work, have a global relaxation time smaller than 0.76 ps and larger than 0.20 ps. A comparison between different ranges of FT-Raman and SERS band parameters of DNA extracted from leaf tissues, respectively, is given. We have found that the bands of DNA from Romus 3 and Rebra cultivars are suitable for studying the dynamical behaviour of molecular subgroups, in genomic nucleic acids extracted fromin vitro-grown apple plants.


2020 ◽  
Vol 04 ◽  
Author(s):  
Vigen G. Barkhudaryan ◽  
Gayane V. Ananyan ◽  
Nelli H. Karapetyan

Background: The processes of destruction and crosslinking of macromolecules occur simultaneously under the influence of ultraviolet (UV) radiation in synthetic polymers, dry DNA and their concentrated solutions. Objective: The effect of UV radiation on calf thymus DNA in dilute solutions subjected to UV- irradiation was studied in this work. Method: The calf thymus DNA was studied in dilute solutions using viscometry, absorption spectroscopy and electrophoresis. Results: It was shown, that at a low concentration of DNA in the buffer solution ([DNA] = 85 μg / ml) under the influence of UV radiation, the processes of destruction of macromolecules and an increase in their flexibility predominate, which is accompanied by a gradual decrease in the viscosity of their solution. In addition, due to the low concentration of the solution, intramolecular crosslinking of macromolecules predominates, which also reduces their size and, consequently, the viscosity of the solution. Conclusion: It was concluded, that in dilute DNA solutions, due to the predominance of the processes of intramolecular crosslinking of macromolecules over intermolecular, only constant processes of decreasing the sizes of DNA macromolecules occur. As a result, its solubility remains virtually unchanged during UV irradiation. The described comments are also excellently confirmed by the results of absorption spectroscopy and electrophoresis


1989 ◽  
Vol 54 (7) ◽  
pp. 2021-2026
Author(s):  
Marie Stiborová ◽  
Befekadu Asfaw ◽  
Pavel Anzenbacher

Ce(IV) ions in acidic medium convert a carcinogenic non-aminoazo dye, 1-phenylazo-2-hydroxy-naphthalene (Sudan I) into an ultimate carcinogen, which binds to calf thymus DNA. The principal product of Sudan I oxidation by the Ce(IV) system is the benzenediazonium ion. A minor product is the dihydroxyderivative of Sudan I, 1-(4-hydroxyphenylazo)-2,6-dihydroxynaphthalene. Other minor coloured products (yellow and brown) were not identified. The principal product (the benzenediazonium ion) is responsible for the carcinogenicity of Sudan I, as it covalently binds to DNA. Ce(IV) ions in acidic medium represent a suitable model system, which imitates the activation route of carcinogenic azo dyes.


MAPAN ◽  
2016 ◽  
Vol 31 (3) ◽  
pp. 169-175 ◽  
Author(s):  
Deepti Chadha ◽  
Shweta Agarwal ◽  
Ranjana Mehrotra

Author(s):  
Cleiton M. da Silva ◽  
Marina M. Silva ◽  
Fabiano S. Reis ◽  
Ana Lúcia T.G. Ruiz ◽  
João E. de Carvalho ◽  
...  

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