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Ovchinnikov YuA

Publications and source records attributed to Ovchinnikov YuA.

At least 37 records · Page 2Linked to original sources
PubMed1985

Three-dimensional structure of (Na+ + K+)-ATPase revealed by electron microscopy of two-dimensional crystals.

Prolonged incubation of membrane fragments containing homogeneous (Na+ + K+)-ATPase with Mg2+, K+ and VO-3 at 4 degrees C resulted in formation of two-dimensional crystals of this enzyme with unit cell parameters: a = 66 A, b = 118 A, gamma = 108 degrees. The crystals correspond to the two-sided plane group p21. By combining tilted electron microscopic views of the crystals, a three-dimensional structure of (Na+ + K+)- ATPase was calculated at approximately 20 A resolution. The unit cell is formed by two (alpha beta)-promoters which are in contact in their central parts. The structure was compared with chemical modification and immunochemical data; the arrangement of intra- and extramembrane domains was proposed.

Animals↗
PubMed1985

1H-NMR study of gramicidin A transmembrane ion channel. Head-to-head right-handed, single-stranded helices.

The structure of [Val1]gramicidin A incorporated into sodium dodecyl-d25 sulphate micelles has been studied by two-dimensional proton NMR spectroscopy. Analysis of nuclear Overhauser effects, spin-spin couplings and solvent accessibility of NH groups show that the conformation of the Na+ complex of gramicidin A in detergent micelles, which in many ways mimic the phospholipid bilayer of biomembranes, is an N-terminal to N-terminal (head-to-head) dimer (Formula: see text) formed by two right-handed, single-stranded beta 6.3 helices with 6.3 residues per turn, differing from Urry's structure by handedness of the helices.

Circular Dichroism↗
PubMed1985

Improved rapid phosphotriester synthesis of oligodeoxyribonucleotides using oxygen-nucleophilic catalysts.

The use of different condensing and phosphorylating agents in conjunction with oxygen-nucleophilic catalysts, such as 4-substituted derivatives of pyridine N-oxide and quinoline N-oxide, leads to a dramatic increase of the rate of the phosphotriester bond formation and minimizes the amount of by-products caused by the modification of heterocyclic bases. The application of these catalysts to the solid-phase oligonucleotide synthesis allows to reduce the time needed for the performance of one elongation cycle on a polymer support to 10 min.

Kinetics↗
PubMed1985

Convenient modification of the method for oligonucleotide-directed in vitro mutagenesis of cloned DNA.

A new modification of the oligonucleotide-mediated mutagenesis technique has been developed. The proposed methodology has been used to produce specific base changes in the double-stranded plasmid DNA. For this purpose, special cloning vectors have been constructed using the synthetic oligodeoxyribonucleotides. The developed method allows the production of mutant DNA from those of the wild-type with a yield of 10-20%.

Base Sequence↗
PubMed1984

Oligomycin sensitivity-conferring protein (OSCP) of beef heart mitochondria. Internal sequence homology and structural relationship with other proteins.

Structural analysis of oligomycin sensitivity-conferring protein (OSCP) revealed repeating sequences (residues 1-89, 105-190) suggesting an evolution of the protein by gene duplication. In addition to the reported homology with the delta-subunit of Escherichia coli F1ATPase, OSCP also shows a certain homology with the b-subunit of E. coli F0 and the ADP/ATP carrier of mitochondria.

Adenosine Triphosphatases↗
PubMed1983

Rapid synthesis of long-chain deoxyribooligonucleotides by the N-methylimidazolide phosphotriester method.

A modified phosphotriester method has been employed for the efficient chemical synthesis of long-chain deoxyribooligonucleotides. During the course of this work, a general and rapid procedure was developed for the preparation of 24-62-mers in solution. Preparative reversed phase column chromatography on silanized silica gel was used to purify triester intermediates starting from 10-mers. The rapid synthesis of 32-mer and 42-mer on glass and silica gel supports using suitably protected 2-8-mer blocks as coupling units has been also accomplished. In particular, a convenient procedure for the solid-phase synthesis of oligonucleotide blocks bearing 3'-terminal phosphodiester groups is described.

Adenylyl Imidodiphosphate↗
PubMed1982

The effect of amine structure on complexation with lasalocid in model membrane systems. II. Ionophore selectivity for amines in lipid bilayers and at oil/water interfaces.

The ionophore antibiotic X-537A (lasalocid) transports biogenic amines across biological and artificial membranes. The major portion of amine flux (greater than 99%) occurs as a 1:1 neutral complex. The rank order of ionophore selectivity was determined for lipid bilayer membrane transport of amines based on a comparison of permeability coefficients: p-tyramine approximately beta-phenylethylamine approximately amphetamine greater than methamphetamine greater than dopamine greater than phenylephrine approximately metanephrine greater than norepinephrine greater than epinephrine. This rank order is in agreement with results obtained from partitioning measurements which were carried out in parallel to the bilayer membrane experiments. A correlation between amine structure and binding characteristics has been developed.

Amines↗
PubMed1982

The primary structure of E. coli RNA polymerase, Nucleotide sequence of the rpoC gene and amino acid sequence of the beta'-subunit.

The primary structure of the E. coli rpoC gene (5321 base pairs) coding the beta'-subunit of RNA polymerase as well as its adjacent segment have been determined. The structure analysis of the peptides obtained by cleavage of the protein with cyanogen bromide and trypsin has confirmed the amino acid sequence of the beta'-subunit deduced from the nucleotide sequence analysis. The beta'-subunit of E. coli RNA polymerase contains 1407 amino acid residues. Its translation is initiated by codon GUG and terminated by codon TAA. It has been detected that the sequence following the terminating codon is strikingly homologous to known sequences of rho-independent terminators.

Amino Acid Sequence↗
PubMed1982

The effect of amine structure on complexation with lasalocid in model membrane systems. I. Identification of charged complexes in lipid bilayer membranes.

The electrical properties of X-537A (lasalocid) doped lipid bilayer membranes were studied in the presence of a series of nine biogenic amines which contain beta-phenylethylamine as the basic structural unit. The ionophore antibiotic was found to form charged complexes within the membrane during the transport of some of the amines. The dependence of membrane conductance on the concentration of ionophore and amine was studied. The amines are divided into three classes according to the nature of the complexes formed: (1) charged complex involving two ionophores (phenylephrine, metanephrine, and amphetamine); (2) charged complex containing three ionophores (dopamine, norepinephrine and epinephrine); and (3) no charged species formed (p- and m-tyramine and beta-phenylethylamine).

Biogenic Amines↗
PubMed1982

Interaction surfaces of neurotoxins and acetylcholine receptor.

Binding of neurotoxin II Naja naja oxiana derivatives containing one spin label at various positions (Leu 1, Glu 2, Lys 15, Lys 25, Lys 26, His 31, Lys 44 and Lys 46) to purified solubilized acetylcholine receptor protein (AchR) from Torpedo marmorata was studied by EPR techniques. AchR interaction with several dansylated neurotoxin II derivatives was followed by difference fluorescence spectroscopy. A series of neurotoxin II p-azidobenzoyl derivatives were prepared and in three of them modified lysine residues were identified. In combination, spectroscopic data and photolabeling implicate a considerable area of the neurotoxin in association with AchR. Rigidity of the neurotoxin II conformation allowed to regard its binding surface as a mould of the AchR corresponding site and to estimate the minimal size of the latter. Conformation of the long-chain neurotoxins and their binding to AchR are briefly discussed basing on the 1H and 19F NMR studies of neurotoxin I Naja naja oxiana, toxin 3 Naja naja siamensis and its acetylated or trifluoroacetylated derivatives, as well as on Achr interaction with the derivatives spin labeled at Lys 27 and His 71.

Acetylcholine↗