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Query: UNIPROT:P06889 (Mol)
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The formation of compact double-stranded DNA molecules in PEG-containing watersalt solutions (0.3 M NaCl) may be observed within the pH-range 3-10; i.e. under conditions at which parameters of double-stranded DNA helices are not strongly different from those of B-form. At pH less than 3, when regularity of double helices is significantly changed, the formation of the specific compact particles of DNA in PEG-containing solutions does not take place. Denaturation of the compact form of DNA in PEG-containing solution is accompanied by disappearance of the negative band in CD spectrum. Hyperchromic effect of denaturation of DNA compact form is uninformative because of the influence of the light-scattering by compact DNA molecules.
Mol Biol (Mosk)
PMID:[A compact form of DNA in solution. 2. Peculiarities of acidic titration of double-stranded DNA in PEG-containing water-salt solutions]. 0 28

Influence of pH on absorbance and CD-spectra of DNA in PEG-containing water-salt solutions has been studied. The changes in the spectra appeared due to disturbance of the DNA secondary structure upon acidification of the medium proir to or after DNA compactization. If acidification preceeds DNA compactization an intense negative band in the CD spectrum inherent to the compact particles is observed at pH values 7-4. The intensity of the band decreases with an increase of the acidity. The size of the compact particles as evaluated from the dependence of the apparent optical density on the wavelength value remains unchanged (about 1200 A). If the solution is strongly acidified (pH 4.0-2.8) and a considerable disturbance in the DNA secondary structure takes place a negative band in the CD spectrum completely disappears. If one acidifies a solution containing preformed DNA compact particles a decrease of the intensity of the CD negative band starts at lower pH values (less than 2.8). This process is accompanied by an increase of the size of the particles. Acidic "denaturation" of DNA within the compact particles (pH approximately 2.5) is followed by a dissappearance of the CD negative band and a considerable increase of the particle size. The data obtained indicate that the specific arrangement of DNA strands manifested in a CD negative band depends on the defects in the DNA secondary structure.
Mol Biol (Mosk)
PMID:[The compact form of DNA in solution. IV. The effect of secondary structure defectiveness on the arrangement of double-chained DNA molecules into compact particles]. 0 1

Double-stranded polyribonucleotides (a replicative form of phage f2 RNA--dsRNA and poly(A) poly(U), can adopt a compact from in solutions, containing NaCl and poly(ethylene glycol) (PEG). According to electron-microscopic observations dsRNA compact particles have the form of disks or doughnuts 200--400 A in diameter. X-ray diffraction patterns from dense slurries of dsRNA compact particles show a reflection at a spacing of 35 A, which is indicative of the existance of ordered regions in compact particles. The intense positive CD band, which is characteristic of dsRNA and poly(A) poly(U) compact particles, presumably results from the ordered regions in the particles. Heating of the solution leads to the disappearance of the intense positive CD band, probably as a result of the destruction of the ordered structure of compact particles. Heat or acid denatured dsRNA molecules as well as single-stranded molecules of ribosomal RNA also form large particles in PEG-containing solutions. However, X-ray diffraction patterns from these particles do not show the 35 A reflection and the specific positive band is not present in their CD spectra, which indicates that such particles lack ordered internal structure. It is suggested that similar mechanism of compactization of double-stranded polynucleotides (DNA and RNA) exist, and compact particles may be divided into two families (psi+ and psi-), differing by the secondary structure of double-stranded polynucleotides, which form the particles.
Mol Biol (Mosk)
PMID:[Compact form of DNA in solution. XII. Double-stranded polyribonucleotide compacting in the presence of polyethylene glycol]. 3 51

A highly efficient method for transformation of Bacillus subtilis by plasmid DNA is reported. The procedure, which involves polyethylene glycol-induced DNA uptake by protoplasts and subsequent regeneration of the bacterial cell wall, yields up to 80% transformants with an efficiency of 4 x 10(7) transformants per microgram of supercoiled DNA. Plasmids constructed by in vitro ligation or endonuclease-generated fragments of linear plasmid DNA can also transform PEG-treated protoplasts, but at a lower frequency.
Mol Gen Genet 1979 Jan 05
PMID:High frequency transformation of Bacillus subtilis protoplasts by plasmid DNA. 10 88

Conditions of formation of the DNA optically-active compact particles (e. g. particles which are characterized by intense negative band in CD spectrum) in PEG-containing solutions of NaCl, NaClO4, KCl, KBr, KI and CsCL have been studied. It has been shown that the region of existence of the DNA optically-active compact particles is restricted not only by the definite concentration of PEG, but also by the definite ionic strength of solution. Above this region the intense band in CD spectra of the DNA compact particles is practically absent. The nature of cation influences the process of compactization (condensation) of the DNA double-stranded molecules; the nature of anion does not influence this process (up to 0,3 M salt concentration).
Mol Biol (Mosk)
PMID:[Conditions of formation of DNA optically-active particles in polyethyleneglycol-containing solutions of different salts]. 47 Sep 38

Different physico-chemical methods (CD, ORD, small-angle X-ray diffraction, etc) were used for investigating the properties of the DNA compact particles formed in PEG-containing water-salt solutions. It has been shown that small-angle reflection, characteristic of the DNA compact particles, changes from 36.8 A (CPEG = 140 mg/ml) to 25 A (CPEG = 300 mg/ml). The maximal optical activity (the intense negative CD-band and optical rotation [alpha] = 60 000 degrees) are inherent properties of the DNA compact particles formed at CPEG 120--180 mg/ml. The high optical activity points to the twist of DNA chromophores through the DNA molecule resulting in a long-rang pitch (P approximately 2000A). Such macroscopic superhelical structure (diameter 40--30 A) is due to conformational distortion of the DNA double-helix with alternating "left" and "right" orientation of chromophoes. Disappearance of conformation distortion is accompanied by disappearance of the high optical activity of the DNA compact particles and results in a small-angle reflection of 25 A. Taking into account the reasons of formation of the optically-active DNA compact particles conditions are suggested to conserve high optical activity at CPEG equal to 400 mg/ml.
Mol Biol (Mosk)
PMID:[Correlation between conformation distortion of the DNA sugar-phosphate backbone and high optical activity of its compact form]. 50 60

The interaction between various fractions of neurospecific S-100 protein and calcium was studied by means of differential spectrophotometry. Fractions demonstrating "blue" and "red" shifts of the spectrum were detected. The change of conformation, occurring when calcium is bound, results in a redistribution of the protein in the double-phase system (polyetylenglycol-dextran), and the fractions, demonstrating the "blue" shift are transferred to the more hydrophobic phase (PEG), while fractions with the "red" shift move to the less hydrophobic phase (dextran). The existence of fractions with different reaction to calcium binding is discussed considering their participation in controling ionic permeability of neuronal membranes.
Mol Biol (Mosk)
PMID:[Reaction between calcium and different protein S-100 fractions]. 65 77

The formation of compact particles from synthetic double- and triplestranded polynucleotides in water-salt solutions, containing poly(ethylene glycol) (PEG) has been investigated. CD spectra of compact particles are characterized by intense bands (positive or negative) in the region of 270 nm, compact particles being divided into two families--psi- and psi+--according to the CD band sign. The amplitude of the CD band at 270 nm increases with the increase of CPEG. Heating of a solution, containing compact particles, results in a disappearance of the CD band, the "melting" of compact particles as revealed by the CD method occuring prior to the melting of the secondary structure of the corresponding polynucleotide. It is concluded that intense CD bands, which are characteristic of the compact form of synthetic polynucleotides, arise (similar to the case of DNA or dsRNA) from regular arrangement of polynucleotide chains in compact particles. The question, concerning the relation between parameters of the secondary structure of polynucleotides and their belonging either to psi- or to psi+ family is discussed. The factors, which could account for the appearance of intense bands in CD spectra of compact particles are also considered.
Mol Biol (Mosk)
PMID:[Compact form of synthetic polynucleotides. Relationship between secondary structure and circular dichroism spectra]. 65 79

The dependence of viscosity of the water solutions of poly(ethylene glycol) (PEG) on the molecular weight has been studied. It has been shown that there is a "transitional" region in PEG properties which accounts for the formation of fluctuation polymer network of the PEG molecules. It has been shown that the "transitional" region in properties of PEG which appears at a certain concentration of PEG (CtrPEG) is characteristic of the PEG preparations with molecular weights exceeding 600 and dependence of the value of CtrPEG on the molecular weight of PEG was obtained. Compactization of double-stranded DNA molecules in PEG-containing water-salt solutions has been studied and the dependence of the value of CcrPEG, . i.e. the concentration of PEG at which the compact particles of DNA appear in the solution, on the molecular weight of PEG was obtained. The correlation between these two dependences reflecting quite different physico-chemical processes shows that the double-stranded DNA molecules are constrained within the polymer network of the PEG molecules. The influence of ionic strength and ionic composition of the solution on the formation of a compact form was investigated. The transition of the DNA molecules from a linear to a compact state may occur only at a definite value of ionic strength of the solution. This transition may occur at the change of K+ for Na+ cations (at a constant value of CPEG). The extent of compactization of the DNA molecules in PEG-containing water-salt solutions is monitored by the molecular structure and by the ionic strength of the solvent. It is supposed that the peculiarities of compactization of the DNA molecules in PEG-containing water-salt solutions reflect some characteristics of conformational transitions of the DNA molecules which occur in vivo.
Mol Biol (Mosk)
PMID:[Relationship between the molecular structure of aqueous solutions of polyethylene glycol and the compactness of double-stranded DNA molecules]. 66 17

The experimental data indicating that the amplitude of the negative band in CD spectra of DNA compact particles forming in PEG-containing water-salt solutions intensifies with the decrease of DNA molecular weight are presented. This effect is not explained by the light scattering on the compact particles. The presence of the negative band in CD spectrum of DNA compact particles is interpreted as result of formation of dichrographic-active "microcrystalline" region ("domains") (if DNA compact particles are formed from double-stranded molecules with unaltered secondary structure); it is also supposed that the number of these regions in the particle and their dichrographic activity doesn't depend on the particles size. This interpretation is in agreement with experimental data on the increase of the number of compact particles with the decrease of DNA molecular weight. Proportionality coefficient in the linear dependence of the amplitude of negative band on the size of DNA compact particles in solution depends apparently on dichrographic activity of "microcrystalline" regions, and this activity is connected with structural peculiarities of initial DNA molecules.
Mol Biol (Mosk)
PMID:[Compact form of DNA in solution. X. Peculiarities of circular dichroism spectra of DNA compact particles forming polyethylene glycol-containing water-salt solutions]. 75 78


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