Hydroxycobalamin catalyzes the oxidation of diethyldithiocarbamate and increases its cytotoxicity independently of copper ions.

It is known that some metals (Cu, Zn, Cd, Au) markedly increase the toxic effect of thiocarbamates. It was shown in the present study that hydroxycobalamin (a form of vitamin B12, HOCbl), which incorporates cobalt, significantly enhances the cytotoxicity of diethyldithiocarbamate (DDC), decreasing its IC50 value in tumor cells three to five times. The addition of HOCbl to aqueous DDC solutions accelerated the reduction of oxygen. No hydrogen peroxide accumulation was observed in DDC + HOCbl solutions; however, catalase slowed down the oxygen reduction rate. Catalase as well as the antioxidants N-acetylcysteine (NAC) and glutathione (GSH) partially inhibited the cytotoxic effect of DDC + HOCbl, whereas ascorbate, pyruvate, and tiron, a scavenger of superoxide anion, had no cytoprotective effect. The administration of HOCbl into DDC solutions (> 1 mM) resulted in the formation of a crystalline precipitate, which was inhibited in the presence of GSH. The data of UV and NMR spectroscopy and HPLC and Mass Spectrometry (LC/MS) indicated that the main products of the reaction of DDC with HOCbl are disulfiram (DSF) and its oxidized forms, sulfones and sulfoxides. The increase in the cytotoxicity of DDC combined with HOCbl occurred both in the presence of Cu2+ in culture medium and in nominally Cu-free solutions, as well as in growth medium containing the copper chelator bathocuproine disulfonate (BCS). The results indicate that HOCbl accelerates the oxidation of DDC with the formation of DSF and its oxidized forms. Presumably, the main cause of the synergistic increase in the toxic effect of DDC + HOCbl is the formation of sulfones and sulfoxides of DSF.

[NMR study of human biological fluids for detection of pathologies].

The paper deals with the NMR spectra obtained using preparations of five different human biological body fluids. Characteristic metabolite signals of blood, urine, tears, saliva, and sweat spectra have been determined and classified. The biological body fluid samples were used for search and identification of biomarkers of cardiovascular disease. Absolute functional biomarkers for diseases such as coronary heart disease (CHD) have not been recognized even in the case acute myocardial infarction. A hypothesis explaining reasons of lack of such markers has been formulated. The results of comparative analysis of blood and urine samples from humans and some laboratory animals are given. Identify and analyze signals of metabolites of pathogenic microflora and their dynamics in the urine from patients with urogenital diseases have been determined and analyzed and characteristic biomarkers have been recognized.

[NMR studies of water-gas interactions].

The analysis of reported data concerning the solubility of different gases in water depending on a temperature was carried out. These dependences could be described by mono- or biexponential function. Solubilities of nitrogen and oxygen are additive and depend on their percentage in the atmosphere above the fluid. The temperature dependence of oxygen and nitrogen dissolved in water corresponds to that in the atmospheric air. The measurements of water spin-lattice relaxation times changing upon the concentration of dissolved paramagnetic oxygen showed that the oxygen could be significantly but not completely eliminated by saturation with any gases. The best method is the contact with a water immiscible liquid with higher gas capacity than water. However, it results in unstable state of a gas-water system converging to equilibrium.

[Purification of the mitochondrial calcium uniporter from the beef heart and characterization of its properties].

A low-molecular-weight component (LMC) inducing selective transport of calcium across the bilayer lipid membrane has been isolated from mitochondria of the bovine heart by the method developed in our laboratory, which excludes the use of detergents and proteolytic enzymes. It was shown that, in the presence of 10 mM CaCl2, LMC forms conduction channels in the membrane multiples of 5 pS. The specific inhibitor of mitochondrial calcium uniporter, ruthenium red, closes Ca2(+)-induced channels formed in the membrane by LMC. In the absence of calcium or in the presence of potassium ions only, the component is incapable of forming channels of conduction. It was shown using nuclear magnetic resonance that LMC is a complex consisting of lipids, amino acids, and sugars with a molecular weight of 1-2 kDa.

[Chimeric SHA-D domain ("SH3-Bergerac"): 3D-structure and dynamics studies in solution].

Protein SHA-D of "SH3-Bergerac" chimeric proteins family was constructed by substitution of beta-turn N47-D48 in spectrin SH3-domain by KATANDKTYE amino acid sequence. Structural and dynamics properties of SHA-D in solution were studied by with the help of high-resolution NMR. The extension of SHA-D polypeptide chain in comparison with wild type of protein WT-SH3 (~ 17%) practically doesn't affect almost the total molecule topology. 3D-structure of SHA-D is practically identical to the proteins of "SH3-Bergerac" family. However there are some differences in dynamic characteristics in the region of substitution. The G52D substitution in SHA-D protein results in a destabilization of the region insertion where the conditions for conformational exchange appear. Destabilization further affects the entire SHA- D molecule making its structure more labile.

[NMR structure and dynamics of the chimeric protein SH3-F2].

For the further elucidation of structural and dynamic principles of protein self-organization and protein-ligand interactions the design of new chimeric protein SH3-F2 was made and genetically engineered construct was created. The SH3-F2 amino acid sequence consists of polyproline ligand mgAPPLPPYSA, GG linker and the sequence of spectrin SH3 domain circular permutant S19-P20s. Structural and dynamics properties of the protein were studied by high-resolution NMR. According to NMR data the tertiary structure of the chimeric protein SH3-F2 has the topology which is typical of SH3 domains in the complex with the ligand, forming polyproline type II helix, located in the conservative region of binding in the orientation II. The polyproline ligand closely adjoins with the protein globule and is stabilized by hydrophobic interactions. However the interaction of ligand and the part of globule relative to SH3 domain is not too large because the analysis of protein dynamic characteristics points to the low amplitude, high-frequency ligand tumbling in relation to the slow intramolecular motions of the main globule. The constructed chimera permits to carry out further structural and thermodynamic investigations of polyproline helix properties and its interaction with regulatory domains.

[Study of the structure and dynamics of a chimeric variant of the SH3 domain (SHA-Bergerac) by NMR spectroscopy].

A structural-dynamic study of one of the chimeric proteins (SHA) belonging to the SH3-Bergerac family and containing the KATANGKTYE sequence instead of the N47D48 beta-turn in the spectrin SH3 domain was carried out by high resolution NMR spectroscopy. The spatial structure of the protein was determined and its dynamics in solution was investigated on the basis of the NMR data. The elongation of the SHA polypeptide chain in comparison with the WT-SH3 original protein (by ~17%) exerts practically no effect on the general topology of the molecule. The presence of a stable beta-hairpin in the region of insertion was confirmed. This hairpin was shown to have a higher mobility in comparison with other regions of the protein.

[Use of NMR spectroscopy in studies of sorbitol and glucose transformation by Gluconobacter oxydans].

NMR spectroscopy was applied for studying the products of glucose and sorbitol oxidation by cells of Gluconobacter oxydans. An analysis of 1H NMR spectra showed that the transformation of glucose results in the formation of diketogluconic acid, and sorbitol is oxidized to sorbose. In the 32P NMR spectra, only a signal of inorganic phosphate was detected, which accumulated in the medium as a result of cell lysis.

[Studies of interactions of carbonic anhydrase B with water and urea: II. Spin diffusion of associates of protein intermediate state at 4.2 M of urea].

The formation of carbonic anhydrase B associates (pH 5.7, urea concentration 4.2 M, 297 K) was studied as a function of protein concentration and time by nuclear magnetic resonance spectroscopy (spin diffusion method). It was found that the association process proceeds in two steps. The first step is relatively fast and cannot be controlled by our methods. During this step, persistent units are built. These consist of protein molecules that are able to interact with solvent molecules and with each other when protein solution contains 4.2 M of urea. Persistent units are relatively small (two, three protein molecules), and their mobility matches one of a single protein. The second step is slower, and throughout this step large structures are formed from persistent units. The parameters G* and S*, which characterize spin diffusion in a protein and a solvent, respectively (when spin diffusion excitation happens away from NMR spectral signals) are related to the probable size distribution of protein-solvent associates and are determined by their collective properties.

[A study of interactions of carbonic anhydrase B with water and urea. I. Spin-diffusion parameters that determine individual and cooperative properties of molecules].

The rigidity parameter (G), which is characteristic of protein compactness, was studied in native globular carbonic anhydrase B. The dependence of parameter G on power and excitation time of spin-diffusion was expressed analytically. We found out that native carbonic anhydrase B is able to form water-protein units that are probabilistically distributed with respect to their sizes. Large water-protein units can be detected by analyzing the spin-diffusion spectra. The excitation frequencies of spin-diffusion spectra were shifted far away from typical 1H NMR spectra of carbonic anhydrase B.

[Carbonic anhydrase B interactions with water and urea].

Carbonic anhydrase B unfolding with urea (pH 5.7, T = 298 K) was studied by high-resolution NMR spectroscopy. The effectiveness of spin-diffusion influencing compactness of the protein molecule can be described with the rigidity parameter G. Parameter G displays sigma-like characteristic behavior when concentration increases. The ratio between integral intensities of urea and protein signals in spin-diffusion and normal 1D spectra are the same. This suggests that there is no predominant urea-protein molecular interaction. The concentration of large protein-solvent associates increases rapidly at urea levels of 4.2-6.2 M implying that protein molecule shifts to a molten globule state. Protein-solvent associates are dissipating with urea concentration increase to above 6.6 M when carbonic anhydrase B polypeptide chain is completely unfolded.

[Spin diffusion in globular proteins: alpha-lactalbumin]. / Spinovaia diffuziia v globuliarnykh belkakh: al'fa-laktal'bumin.

The structural properties of globular proteins analyzed by two different methods: high-resolution NMR and circular dichroism were compared. We established that the spin diffusion method shows changes in the secondary structure during the unfolding of the alpha-lactalbumin molten globule by urea. It was shown that the spin diffusion method is extremely effective in studies of interactions of water and denaturant molecules with the protein both in the native and the molten globule states.

[Effect of heavy water on metabolism of a symbiotic organism]. / Vliianie tiazheloi vody na metabolizm simbioticheskogo organizma.

The metabolism of the symbiotic organism medusomycete (tea fungus) and the influence of D2O on its development was studied by high-resolution NMR methods using isotopically enriched (by 13C and 2H) metabolites. The results demonstrate that D2O influences the selective utilization of certain protonated substrates during the formation of triose phosphates. It was found that protonated isotopomers derived from the first glucose fragment C1-C2-C3 are predominantly utilized. This explains why the metabolism slows down by a factor of 2 to 3 if D2O concentration in the medium increases. It was also shown that approximately 10% of the organisms are in the state of dynamic extracellular endosymbiosis. This state is characterized by the ability to exchange the metabolic products through close intercellular contacts. As a result of the metabolic exchange, a multicellular organism is formed, with metabolic elements localized in different partners. A distinguishing feature of this organism is the ability to accumulate the internal resources of carbon, thus making it better adapted to the unfavorable environment.

[Guanidine hydrochloride mediated unfolding of a carbonic anhydrase molten globule]. / Razvorachivanie rasplavlennoi globuly karboangidrazy guanidingidrokhloridom.

Guanidine hydrochloride-induced unfolding of a carbonic anhydrase molten globule was studied by high-resolution NMR spectroscopy. The study resulted in estimation of the number of water and denaturant molecules bound to the molten globule at various denaturant concentrations in solution. When compared with the data on unfolding of native carbonic anhydrase, these estimates indicate that the unfolding is underlain by an increased local concentration of the denaturant near the protein molecule, which results from the increased ratio between guanidine hydrochloride-bound and protein-bound waters.

[Medusomyces (tea fungus): scientific history, composition, physiology, and metabolism]. / Meduzomitset (chainyi grib): nauchania istoriia, sostav, osobennosti fiziologii i metabolizma.

The literature data on medusomyces published since 1913 are discussed. Different versions of appearance and distribution of this microorganism are considered. The features of its structure, metabolism and growth conditions are analyzed. It is shown that the tea fungus is a symbiosis is of several sorts of yeast and acetic acid bacteria. Evidence is presented indicating that fermented tea fungus has a therapeutic effect and can be applied in medicine. It was proved, that the antimicrobial properties of tea fungus metabolic products are due to the presence of particular antibiotic substances. The regularities of the biosynthesis of these substances and the pathways of its stimulation were studied. The results obtained will lead to the large-scale use of tea fungus in biotechnology. The fungus has unique adaptation properties, as confirmed by experiments on cultivation of the organism on deuterium oxide (D2O) and in the conditions of "cold stress". It is suggested that medusomyces is a unique model for the investigation of the phenomenon of symbiosis.