Showing papers by "Russian Academy of Sciences published in 1988"
TL;DR: This chapter focuses on the stability of protein structure and hydrophobic interaction, and examines the main achievements of microcalorimetric studies of protein denaturation and of the dissolution of nonpolar substances in water.
Abstract: Publisher Summary This chapter focuses on the stability of protein structure and hydrophobic interaction The interest in hydrophobic interactions was stimulated by their unusual thermodynamic properties: it is believed that they are governed, not by enthalpic, but by entropic features, characterized by the undesirable entropy decrease of water in the vicinity of nonpolar groups The amount of polar groups in proteins is almost the same as the amount of nonpolar ones; and according to crystallographic studies, most of them are arranged at distances suggesting hydrogen bond formation Hydrogen bonds were invoked to various degrees of importance in explaining the stabilization of the native structure The chapter examines the main achievements of microcalorimetric studies of protein denaturation and of the dissolution of nonpolar substances in water The chapter also discusses calorimetric studies of protein denaturation The denaturational increment of the heat capacity can be partly explained by a gradual melting of the residual structure in the denatured protein on heating The large negative entropy of the transfer of a nonpolar substance to water at room temperature indicates a definite increase of the order in water in the presence of such solutes Of the two approaches to decomposing the thermodynamics for dissolution of nonpolar solutes into water, the first, from a reference point at the maximum of the free energy of transfer, leads to the concept of the compact state of the nonpolar substance
1,231 citations
TL;DR: A computerised approach to the structural analysis of unbranched regular polysaccharides is described, which is based on an evaluation of the 13C-n.r.m. spectra for all possible primary structures within the additive scheme starting from the chemical shifts of the13C resonances of the constituent monosaccharides and the average values of the glycosylation effects.
622 citations
TL;DR: A cell-free translation system has been constructed that uses a continuous flow of the feeding buffer through the reaction mixture and a continuous removal of a polypeptide product, and has proven active for long times.
Abstract: A cell-free translation system has been constructed that uses a continuous flow of the feeding buffer [including amino acids, adenosine triphosphate (ATP), and guanosine triphosphate (GTP)] through the reaction mixture and a continuous removal of a polypeptide product. Both prokaryotic (Escherichia coli) and eukaryotic (wheat embryos, Triticum sp.) versions of the system have been tested. In both cases the system has proven active for long times, synthesizing polypeptides at a high constant rate for tens of hours. With the use of MS2 phage RNA or brome mosaic virus RNA 4 as templates, 100 copies of viral coat proteins per RNA were synthesized for 20 hours in the prokaryotic or eukaryotic system, respectively. With synthetic calcitonin messenger RNA, 150 to 300 copies of calcitonin polypeptide were produced per messenger RNA in both types of continuous translation systems for 40 hours.
612 citations
TL;DR: The mechanism of reversible electric breakdown of lipid membranes is studied and hydrophilic pores of an effective radius of 0.6 up to more than 1 nm are formed, which account for the membrane conductivity increase observed.
558 citations
TL;DR: The phosphorylation of EF-2 directly affects the elongation stage of translation and thus represents a novel mechanism of translational control.
Abstract: A new Ca2+/calmodulin-dependent protein kinase has been recently discovered in mammalian cells. The major substrate of this kinase, a protein of relative molecular mass (Mr) approximately equal to 100,000 (100K), has been identified as elongation factor 2 (EF-2), which participates in protein synthesis. The in vivo activity of the EF-2 kinase depends upon growth factors and other agents affecting the level of Ca2+ and cAMP. Its effect on EF-2 activity, however, remained obscure. This work shows that the phosphorylation of EF-2 by the EF-2 kinase results in a drastic inhibition of polyphenylalanine synthesis in poly(U)-directed translation. Phosphorylated EF-2 is completely inactive in translation and, moreover, inhibits the activity of non-phosphorylated EF-2. Dephosphorylation of EF-2 by phosphatase restores its activity. Hence, the phosphorylation of EF-2 directly affects the elongation stage of translation and thus represents a novel mechanism of translational control.
423 citations
TL;DR: The modified Hopfield model defined in terms of "V-variables" (V = 0; 1), which is appropriate for storage of correlated patterns, is considered and the learning algorithm is proposed to enhance significantly the storage capacity in comparison with previous estimates.
Abstract: The modified Hopfield model defined in terms of "V-variables" (V = 0; 1), which is appropriate for storage of correlated patterns, is considered. The learning algorithm is proposed to enhance significantly the storage capacity in comparison with previous estimates. At low levels of neural activity, p 1, we obtain αc(p) ~ (p|ln p|)-1 which resembles Gardner's estimate for the maximum storage capacity.
421 citations
TL;DR: In this article, the authors present a non-equilibrium method for studying anomalous B -nonconservation in the electroweak theory at finite temperature, and derive formally the equation of B -evolution advocated previously on physical grounds.
420 citations
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01 Jan 1988TL;DR: In this paper, it was shown that to create B = 2 µGauss in a disk of R = 15 kpc in radius and h = 0.4kpc in half-thickness, one needs an electromotive force of about BRh/ct = 1010Volts acting for t = 101 0 years.
Abstract: Intensity of galactic magnetic field is minute. it is measured in microgausses. However, the field has a record scale measured in ki-loparsecs. (Unfortunately, the Guinness book does not mention this giant magnet.) To create B = 2 µGauss in a disk of R = 15 kpc in radius and h = 0.4 kpc in half-thickness one needs an electromotive force of about BRh/ct = 1010Volts acting for t = 1010years. F.Hoyle, who first noted the fact, did not see any other possibility except the idea of the relic origin of the galactic magnetic field.
417 citations
TL;DR: Covalent coupling of bovine rhodopsin to CPG‐thiol glass was used for separation of CNBr peptides and it was shown that cysteine residues 322 and 323 in the C‐terminal cytoplasmic fragment of rhodopsy are modified with palmitic acid.
394 citations
TL;DR: In this paper, it was shown that the kinetics of collapse of a polymer coil consisting of N segments after an abrupt decrease of temperature is a two-stage process if N >> Ne.
Abstract: It is shown that the kinetics of collapse of a polymer coil consisting of N segments after an abrupt decrease of temperature is a two-stage process if N >> Ne. The first stage takes a time ∼ N2 and leads to the peculiar state — crumpled, or fractal, globule. Any part of a chain of any scale is itself a globule in this state ; these parts are segregated from each other in space due to the non-phantomness of a chain. The chain fold in the crumpled globule is a fractal line with fractal dimension 3, equal to the space dimension. The second stage is a chain knotting ; it is realized by means of reptation-like mechanism of motion, takes a time ∼ N3 and is accompanied by an increase of globule density.
394 citations
TL;DR: Using a photocross-linking approach, the 20S heat-shock GroEL protein is identified as the major cytosolic component which forms a complex with the unfolded newly synthesized pre-β-lactamase or chloramphenicol acetyltransferase in Escherichia coli.
Abstract: It has been suggested that newly synthesized proteins are maintained in their unfolded state by cellular ATP-driven factors which may prevent or reverse the formation of misfolded structures or promote the correct assembly of oligomeric proteins or post-translational secretion1–6. Using a photocross-linking approach, we have identified the 20S heat-shock GroEL protein as the major cytosolic component which forms a complex with the unfolded newly synthesized pre-β-lactamase or chloramphenicol acetyltransferase in Escherichia coli. Dissociation of these com-plexes is ATP-dependent. The unfolded state of pre-β-lactamase, maintained by the transient interaction with GroEL, may be essen-tial for the secretion of this protein.
TL;DR: The main goal of the present review is to formulate a comprehensive classification of numerous successful nonaqueous biocatalytic systems based on a few fundamental principles.
01 Jan 1988
TL;DR: In this paper, basic stereochemical factors have been revealed which affect the 13C chemical shifts in glycosides with a chiral cyclohexane-type aglycone and in disaccharides with an Aglycone.
Abstract: Basic stereochemical factors have been revealed which affect the 13C chemical shifts in glycosides with a chiral cyclohexane-type aglycone and in disaccharides with a pyranosidic aglycone. The effects of glycosylation depend on the configuration of the anomeric centre of the glycosylating sugar residue (glycone) and on the relative absolute configuration of the glycone and aglycone. When at least one of the carbons of the aglycone, adjacent to the glycosylated carbon, bears an equatorial proton, this dependence is well accounted for by a strengthening or weakening of the spatial interaction between the protons of the glycone and aglycone, caused by a change in the conformation around the glycosidic linkage. Regularities in the glycosylation effects for disaccharides are generalized for various modes of substitution and different general configurations of the pyranosidic aglycones. Simple rules have been formulated for the prediction of the magnitudes of the glycosylation effects which can be used for the determination of some unknown structural elements in glycosides and disaccharides, in particular the absolute configuration of one of the constituent sugars.
TL;DR: A signal of 5 events within 9.1 s was found in the Baksan scintillation telescope with a fiducial mass of 200 t at the KAMIOKANDE-II and IMB times on February 23, 1987 as discussed by the authors.
TL;DR: (1988).
Abstract: (1988). An Outline of Evolution of the Hymenopterous Insects (Order Vespida) Oriental Insects: Vol. 22, No. 1, pp. 115-145.
TL;DR: The compactness and ellipticity of the denatured state of apomyoglobin depend strongly on pH; with a decrease of pH below 4.0, these parameters gradually approach the values of the random coil.
TL;DR: Molecular cloning and sequencing of both the alleles of p53 gene revealed a base-pair change in codon 72 causing arginine----proline substitution in the allele with the additional BglII site.
TL;DR: It is proposed that a compact state having secondary but not rigid tertiary structure and called the ‘molten globule' state may be suitable candidates for protein translocation across biological membranes.
TL;DR: In this article, the propagation of ondes de combustion en milieu homogene is studied. But the propagation conditions for such ondes are not specified, nor conditions for leur propagation.
TL;DR: In this paper, a new mathematical model has been developed which applies the concept of activation energy distribution to the formation of gases in West Siberia, U.S.R. The model allows the calculation of isotope values for different types of organic matter and their dependence on maturity.
TL;DR: The nucleotide sequence of the rpoB gene of Salmonella typhimurium was compared with known sequences from other sources and the conservative regions were detected, allowing some interesting conclusions to be made about the distribution of the functional domains in bacterial RNA polymerase and about the three-dimensional structure of its β subunit.
Abstract: The nucleotide sequence of the rpoB gene of Salmonella typhimurium has been determined in this work. It was compared with known sequences of the gene from other sources and the conservative regions were detected. This allowed some interesting conclusions to be made about the distribution of the functional domains in bacterial RNA polymerase and about the three-dimensional structure of its β subunit.
TL;DR: In this article, the authors investigated the connection of the baryon asymmetry of the universe (BAU) with the Chern-Simons structure of the ground state of gauge theories at high temperatures.
TL;DR: In this article, the second order parasupersymmetric quantum mechanics of one boson and one parafermion degrees of freedom were constructed and the spectra of this class of systems were 3-fold degenerate, at least above the second level.
Abstract: We construct the second order parasupersymmetric quantum mechanics of one boson and one parafermion degrees of freedom. The parasupersymmetry algebra is Q2 Q†+ QQ†Q+Q†Q2=4QH, Q3=0, [H, Q]=0, where H is the Hamiltonian and Q is the para-supercharge. The spectra of this class of systems are 3-fold degenerate, at least above the second level.
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01 Jan 1988TL;DR: A review of the literature on ligand exchange chromatography is presented in this paper, covering the literature up to the end of 1976, covering theoretical questions and peculiarities of ligand-exchange chromatography, the practical applications of this new technique in organic chemistry and biochemistry, the study of coordination compounds, the separation of optical isomers, drugs, etc.
Abstract: A review is presented of the chromatographic separation of substances interacting with the stationary phase through the coordination bond formation in the coordination sphere of a transition metal present in the system, covering the literature up to the end of 1976. Advances in liquid chromatography have been considered in more detail than those in gas—liquid and thin-layer chromatography, since the former provides usually more information about the stoichiometry and mechanism of ligand-exchange processes. The first part of the review describes theoretical questions and peculiarities of ligand-exchange chromatography, the second part deals with the practical applications of this new technique in organic chemistry and biochemistry, the study of coordination compounds, the separation of optical isomers, drugs, etc.
TL;DR: In this paper, satellite data on the electromagnetic structures in the high-latitude ionosphere is presented and the theoretical treatment that is carried out in the present paper is in reasonable agreement with the observations.
Abstract: Satellite (IC-B-1300) data on the electromagnetic structures in the high-latitude ionosphere are presented One can observe three kinds of vortices, namely vortex chains as well as solitary dipolar and monopolar vortex structures The theoretical treatment that is carried out in the present paper is in reasonable agreement with the observations
TL;DR: In this paper, the formulation of the problem and preliminary numerical computation results of the thermosphere-ionosphere-protonosphere system parameters are discussed, as well as preliminary numerical computations of the system parameters.
Abstract: In this paper the formulation of the problem and preliminary numerical computation results of the thermosphere-ionosphere-protonosphere system parameters are discussed.
TL;DR: A survey of results on the development of room-temperature tunable lasers using color centers in ionic crystals and on using color center crystals as nonlinear filters and passive Q switches for neodymium lasers is presented in this article.
Abstract: A survey of results is presented on the development of room-temperature tunable lasers using color centers in ionic crystals and on using color center crystals as nonlinear filters and passive Q switches for neodymium lasers. >
TL;DR: Evidence is presented which supports a previous suggestion that kappa-casein and the fibrinogens are evolutionarily related and confirms previous conclusions that it is unrelated to the calcium-sensitive- casein gene family to which it is linked.
Abstract: 1. The bovine kappa-casein gene has been isolated as a series of overlapping lambda clones and shown to consist of five exons distributed over a total length of approximately 13 kb. Most of the mature protein-coding sequence is contained in a single large exon. 2. Approximately 65% of the gene has been sequenced together with portions of the 5'- and 3'-flanking sequences. The immediate 5'-flanking sequence contains several motifs which are characteristic of upstream regions including a TATA box, a CAAT box, a sequence similar to that recognized by transcription factor AP-1 and a purine-rich sequence resembling that found upstream in all other lactoprotein genes. Other possible regulatory sequences are found upstream of exon 4. 3. The organization of the kappa-casein gene, together with its upstream sequence, confirms previous conclusions that it is unrelated to the calcium-sensitive-casein gene family to which it is linked. Evidence is presented which supports a previous suggestion that kappa-casein and the fibrinogens are evolutionarily related. 4. Intron sequences contain several examples of the A family of the artiodactyl Alu-like repeated sequences, together with a single example of a C-family sequence. The remainders of the introns of the kappa-casein gene, compared with the repeat elements and exons, are A + T-rich. 5. Among the lambda clones isolated, representatives were found of the A and B genetic variants which can be distinguished by restriction-enzyme analysis. Several other examples of polymorphisms in the non-coding region were found.
TL;DR: In this article, the results of analytical and numerical studies of lattice 2D quantum gravity are compared with the recent results of conformal approach developed by Knizhnik, Polyakov and Zamolodchikov.