Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Temperature dependences of absorption and CD spectra of DNA compact particles, formed in water-salt solutions in the presence of poly(ethylene glycol) (PEG), have been compared. It has been shown that the disappearance of a specific negative CD band, characteristic of the DNA compact form, occures prior to the destruction of the DNA secondary structure and is not connected with changes of the number or the size of compact particles. The disappearance of this band is believed to reflect the destruction of ordered structure of microcrystalline regions in DNA compact particles. The temperature, at which this "melting" takes place (taum) increases with the rise of PEG concentration, but always remains below the melting temperature of the DNA secondary structure. The thermodynamic parameters, deltaH and deltaS, which characterize the "melting" of the microcrystalline regions in DNA compact particles, were calculated for each CD "melting" curve and were shown in increase, similarly to taum, with the rise of PEG concentration. These data indicate that the regularity of the internal structure of DNA compact particles depends not only on the structural characteristics of the initial DNA, but also on the solvent properties, in particular, on the PEG concentration.
Mol Biol (Mosk)
PMID:[DNA compact form in solution. XI. Melting of the DNA compact state, formed in water-salt solutions, containing poly(ethylene glycol)]. 75 89

Optical and thermochemical properties of E. coli DNA molecules are compared in solutions containing poly(ethyleneglycol) (PEG) in concentrations at which compactization is not yet observed. It is shown that under conditions preceding DNA compactization (CPEG less than 60 mg/ml) changes in CD spectra occur which suggest that the secondary structure of some DNA fragments is altered. These changes of the secondary structure result from dehydration of DNA molecules in PEG-containing solutions. Electron micrographs of DNA molecules obtained under conditions preceding compactization suggest that under these conditions linear DNA molecules may form "four-stranded" fragments as well as double-stranded "loops".
Mol Biol (Mosk)
PMID:[DNA compact form. VI. Changes of DNA secondary structure under conditions preceding its compaction in a solution]. 80 73

A comparative X-ray study of DNA compact particles, formed in PEG-containing solution from native DNA and from DNA molecules with altered secondary structure was carried out. Low-angle reflections, present in X-ray patterns of compact particles (in powder form) from native DNA, correspond to spacings of 84, 42 and 35 A, while wide-angle reflections correspond to spacings of 12.8; 8.4, 6.0, 4.5, 3.4 A. Low-angle reflections at 84 and 42 A are present also in X-ray patterns of compact particles, formed from DNA molecules with altered secondary structures. These two reflections are believed to be the results of an ordering of DNA molecules within the compact particles. The main features of this ordering appear in the first approximation to be independent on DNA secondary structure. The CD spectra of all types of compact particles, mentioned above, were also studied. It has been shown that the intense negative band (lambda approximately 270 nm) in a CD spectrum appeared only in the case of compact particles, formed from native DNA molecules. The nature of the revealed correlation between the 35 A reflection and the CD negative band is discussed. Data presented in the paper allow one to suppose that the 35 A reflection in X-ray patterns and the CD negative band result from specific interactions between double-stranded DNA fragments spatially brought together in compact particles. Such type of interaction is believed to be characteristic only of native DNA molecules.
Mol Biol (Mosk)
PMID:[DNA compact form. 8. X-ray diffraction study of DNA compact particles, formed in solutions containing polyethylene glycol]. 80 81

Protoplasts of methionine- and lysine-requiring h- mutants isolated from the L972 h- strain of Schizosaccharomyces pombe were fused. The protoplasts were obtained from the cells with enzymes produced by Trichoderma viride. When a mixture of the protoplasts was treated with 30% PEG 4000 solution containing 10 mM CaCl2, cell fusion and complementation was attained with a frequency of 0.17%. Both fusion partners were recovered among the spores after crossing of the fusion products with the strain M210 ade6 h+. Cytological and haploidization examinations showed that the fusion cells are not heterokaryons, and that the increased amount of genetic material is situated in one nucleus.
Mol Gen Genet 1977 Feb 28
PMID:Protoplast fusion of Schizosaccharomyces pombe Auxotrophic mutants of identical mating-type. 86 81

DNA-dependent heat effects accompanying mixing of water-salt (0.3 M NaCl) solutions of PEG and DNA within the range of PEG 10-50 mg/ml at 25 degrees C were determined by the method of difference microcalorimetry. It was found that, unlike optical and hydrodynamical methods, microcalorimetry makes it possible to detect some changes of the DNA-PEG system preceding formation of compact particles of DNA. In the studied range of DNA concentrations (up to 50 X 10(-3) MG/ML) the specific DNA-dependent heat effect is essentially independent of DNA concentration. It is negative and its absolute value increases from 0 to 5 cal/g of DNA in the PEG concentration range from 0 to 35-40 mg/ml after that the rate of its increase raises greatly and at PEG concentration of 50 mg/ml it is equal to 35 cal/g of DNA. It is suggested that the studied DNA dependent heat effects at low concentrations of PEG (less than 40 mg/ml) are caused by dehydration of DNA preceding its compactization.
Mol Biol (Mosk)
PMID:[The compact form of DNA in solution. V. The heat effect preceding compactization of double-chained DNA in PEG containing water-salt solutions]. 94 May 53

The data showing the features of the DNA compactization process in PEG-containing solutions of chlorides of different alkaline metals (LiCl, KCl, RbCl and CsCl) and an ammonium salt (CH3-(CH2)17-N-(CH3)3Br) are presented. The data indicate that the formation of a compact form of the double-stranded DNA in PEG-containing water-salt solutions depends not only on the PEG concentration and ionic strength but on tha cation nature as well. The compactization occurs most easily in the presence of Na+-ions. This indicates a specific character of interaction between Na+-ions and DNA phosphate groups which may be due to an optimum structural fit between the hydrated Na+-ions and orientation of the phosphate groups in the DNA molecule. The nature of forces involved in the processes of the intramolecular compactization and intermolecular aggregation of double-stranded DNA molecules in water-salt solution is discussed. The difference between the effect of Na+ and that of K+-ions on the compactization process at the ionic strengths close to physiological values makes it possible to suggest that the changes of the tertiary structure of double-stranded DNA which accompany its function in vivo may take place under conditions of a decreased water activity at the expense of relatively slight changes in ion composition of the water surrounding DNA.
Mol Biol (Mosk)
PMID:[A compact form of DNA in solution. III. Influence of the ion composition of the solution on the compactization process of double-stranded DNA in the presence of peg]. 121


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