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V V Zverev

Publications and source records attributed to V V Zverev.

At least 19 recordsLinked to original sources
PubMed2005

DFT and IR spectroscopic analysis of p-tert-butylthiacalix[4]arene.

Vibrational analysis of p-tert-butylthiacalix[4]arene based on an experimental mid and far IR spectra is described here. Density functional calculations of a most stable cone conformer related to crystalline solid FT-IR spectra in the temperature range up to 180 degrees C as well spectra of dilute solution have been used to obtain a better understanding of conformational state and a hydrogen bonding of p-tert-butylthiacalix[4]arene. Complete assignments were made for experimental FT-IR spectra of the cone conformer. Heating (up to 180 degrees C) of crystalline p-tert-butylthiacalix[4]arene did not change both conformational and cooperative H-bonding state of its molecules. A temperature spectral effect seems to be due to some relaxation of crystal packing mostly viewed on the OH bands.

Models, Molecular↗
PubMed2005

The hydrogen bonding and conformations of p-tert-butylcalix[4]arene as studied by IR spectroscopy and by DFT calculations.

IR and far IR spectra of p-tert-butylcalix[4]arene were recorded at various temperatures between 16 and 180 degrees C and spectra of solutions and crystalline solids were obtained. Ab initio density functional calculations gave vibrational frequencies and infrared intensities for four conformers: cone, partial cone, 1,2- and 1,3-alternate. Complete assignments were made for experimental IR spectra of the cone conformer. The bands characteristic for each conformation were defined. It was revealed that O--H stretching low-frequency shift Deltanu in the cone conformation exceeds Deltanu shifts for other conformers. The effect was stipulated by a cooperative interaction of cyclic hydrogen bonds. The obtained spectra-structure correlation can be used for characteristic of calixarenes conformation.

Calixarenes↗
PubMed1994

Construction and expression in Escherichia coli of hybrid genes composed of sequences encoding diphtheria toxin and human CD4 receptor.

Derivatives of natural toxins possessing substituted receptor-recognition domains of different specificities can be used as instruments for the selective elimination of target cells. We have constructed two different types of hybrid genes that encode proteins composed of diphtheria toxin (DT) lacking the C-terminal residues that mediate toxin binding fused with the N-terminal region of human CD4 (Lys10 to Glu152). One of these hybrids encodes a protein with CD4 at the N terminus, while the other encodes a protein with CD4 at the C terminus. The stability of these two proteins was dramatically different. We could not detect a full-size product when the first construct was expressed in Escherichia coli. In contrast, proteins encoded by the second construct were more stable. In the latter case, the amount of full-size hybrid protein was 1-2% of the total cell protein. We speculate on the involvement of the region that resembles the processing site of Pseudomonas aeruginosa exotoxin A in the proteolytic degradation of the product encoded by the first type of hybrid.

Amino Acid Sequence↗
PubMed1994

[Localization of the CD4 receptor gene in the chromosomes of clone cells of the monocytoid line U-937 characterized by different sensitivities to HIV].

Karyotypes of two clones of U-937 line, with high and low sensitivity to HIV-1, were studied. The CD4-receptor gene-cellular receptor of HIV-1 was mapped. CD4-receptor gene was located according to in situ hybridization method, in locus 12 p11-p12, both in cells of high-sensitive clone U-937/16, and in cells of low-sensitive clone U-937/4. It is determined that in both the clones chromosomes 12 are presented in two copies and are not affected by rearrangements. That allows to conclude that the sensitivity of cells U-937 to HIV-1 does not depend on the dose of this gene, or on its transference in chromosomes.

CD4 Antigens↗
PubMed1991

[Cloning and expression of the CD4 receptor gene from human T-lymphocytes in Escherichia coli cells].

The gene for the CD4-membrane glycoprotein-receptor for HIV has been cloned. The 179 amino acids fragment of the CD4-receptor responsible for binding of gp120 HIV glycoprotein has been fused with beta-galactosidase and shown to be expressed in Escherichia coli cells. The recombinant protein in ELISA and immunoblotting techniques reacts with the monoclonal antibodies OKT4A and Leu3A known to block the interaction between the CD4 and gp120 HIV glycoprotein. The recombinant protein can be used for different scientific and practical purposes including studying of the mechanisms for HIV interaction with the sensitive cells as well as for viral gp120 protein purification, etc.

Base Sequence↗
PubMed1985

The nucleotide sequences of the replication origins of plasmids ColA and ColD.

The nucleotide sequences of the replication origin regions of plasmids ColA-CA31 and ColD-CA23 were obtained. Analysis of the nucleotide sequences showed a high degree of homology of these regions with the plasmid ColE1 region responsible for its autonomous replication. In the ColA and ColD regions involved in the regulation of replication, sites have been revealed identical to those participating in the transcription initiation of the ColE1 plasmid RNA I and primer RNA. The presumed RNA polymerase binding sites and the RNA polymerase recognition sequences are identical in ColA, ColD, and ColE1 plasmids. In spite of the differences in the nucleotide sequences, RNA I and the preprimer RNA of ColA and ColD may form structures analogous to the respective structures of ColE1.

Bacteriocin Plasmids↗
PubMed1985

[Nucleotide sequence of the replicative region of the plasmid ColA-CA31].

ColA-CA31 plasmid DNA region, responsible for the autonomous replication, has been sequenced. The replicative regions of plasmids ColA and ColE1 share the high homology demonstrated in the paper. DNA nucleotide sequences necessary for initiation of RNA I and primer RNA transcription were localized on the ColA genome. RNA I and preprimer RNA of ColA and ColE1 have the similar secondary structure including three palindromes. The absence of homology in ColA and ColE1 hair-pin loops suggests the compatibility of these two plasmids.

Base Sequence↗
PubMed1985

[Characteristics of replication of small colicinogenic plasmids].

Specificity of small multicopy colicinogenic plasmids ColA, ColD, ColE2 and ColK replication has been compared with the one of ColE1 plasmid. Copy number for these plasmids per host cell has been estimated under the normal conditions of cellular growth and under the conditions of chloramphenicol-inhibited growth. DNA polymerase I and dnaB protein, an obligatory component for elongation step in replication, have been shown to be necessary for the plasmids replication. Initiation of plasmids replication has been demonstrated to be independent of dnaA and dnaC proteins. Replication of plasmid ColE2, being similar in its main features to replication of other plasmids from this group, has an important distinction. It requires de novo protein synthesis implying that ColE2 replicon may be different from ColA, ColD, ColK, ColE1 replicons. Thus study of the inducible A, D, K, El colicin synthesis coded by the corresponding plasmids has revealed the similarity regulation of genes, determining the synthesis of each of the mentioned colicins.

Bacteriocin Plasmids↗
PubMed1985

[Clinico-physiological substantiation of using various methods of anesthesia in operations on the lungs in patients with chronic respiratory insufficiency].

The investigation of gas exchange, central hemodynamics and real oxygen transport has shown expediency of using ether and fluothane as main anesthetic drugs in operations on the lungs in patients with a compensated form of chronic pulmonary respiratory insufficiency. Neuroleptoanalgesia decreased the operative risk as compared with ether and fluothane. A combined anesthesia with sodium hydroxybutyrate in association with drugs for NLA and tranquilizers is thought to be the method of choice in patients with a pronounced respiratory insufficiency.

Anesthesia, General↗
PubMed1984

Regions of homology in small colicinogenic plasmids.

Restriction maps have been constructed for the colicinogenic plasmids (ColA, ColD, and ColK. Their regions of homology with the ColE1 plasmid and its deletion derivative pAO3 carrying the region responsible for autonomous replication of ColE1 plasmid were determined by means of blotting hybridization and heteroduplex analysis. The plasmids ColA, ColD, and ColK were shown to contain DNA fragments homologous to the region of ColE1 involved in the regulation of replication.

DNA Replication↗
PubMed1982

[Replication characteristics of colicinogenic plasmid ColK in Escherichia coli cells].

A fraction of plasmid DNA from K and X colicins producing Escherichia coli K235 cells was studied. Cells of this strain are shown to contain four types of plasmids with molecular weights of 21.6.10(6), 38.8.10(6) daltons. Transformation of E. coli C600 by a total plasmid DNA yielded clones containing a single plasmid - colicinogenic K factor (ColK, a mol wt 4.4.10(6)). ColK DNA is present in cells in a large number of copies, replicates in the presence of chloramphenicol, requires DNA polymerase I. Two fragments with mol wts 3.4 and 1.1.10(6) are formed when ColK DNA is treated with EcoRI enzyme. After circularization using phage T4 DNA ligase, the 3.4.10(6) fragment was capable of autonomous replication and stable maintenance in E. coli cells, replicated in the presence of chloramphenicol and though unable to synthesize colicin, confered upon cells resistance to colicin K. The mode of ColK DNA replication is studied in mutants temperature-sensitive for the replication of chromosomal DNA. ColK DNA replication is shown to be virtually independent of the dnaA gene product and only slightly dependent on that of the dnaC gene. No replication occurs in the dnaB, dnaF and dnaG mutants at non-permissive temperature.

Chloramphenicol↗