In silico design of high-affinity ligands for the immobilization of inulinase.

Using computer modeling, virtual screening of high-affinity ligands for immobilization of inulinase - an enzyme that cleaves inulin and fructose-containing polymers to fructose - has been performed. The inulinase molecule from Aspergillus ficuum (pdb: 3SC7) taken from the database of protein structures was used as a protein model and the target for flexible docking. The set of ligands studied included simple sugars (activators, inhibitors, products of enzymatic catalysis), as well as high-molecular weight compounds (polycation and polyanion exchange resins, glycoproteins, phenylalanine-proline peptide, polylactate, and caffeine). Based on the comparative analysis of the values of the total energy and the localization of ligand binding sites, we made several assumptions concerning the mechanisms of interaction of the suggested matrices for the immobilization of enzyme molecules and the structural features of such complexes. It was also assumed that the candidates for immobilization agents meeting the industrial requirements may be glycoproteins, for which we propose an additional incorporation of cysteine residues into their structure, aimed to create disulfide «anchors¼ to the surface.

[Experience in simulating the structural and dynamic features of small proteins using table supercomputers].

The results of theoretical studies of the structural and dynamic features of peptides and small proteins have been presented that were carried out by quantum chemical and molecular dynamics methods in high-performance graphic stations, "table supercomputers", using distributed calculations by the CUDA technology.

Calorimetric and structural studies of tetrabutylammonium chloride ionic clathrate hydrates.

Three ionic clathrate hydrates of different water content are formed in the binary system tetrabutylammonium chloride-water. The data on heats of fusion of these hydrates measured by DSC are presented. Single-crystal and powder X-ray diffraction studies of ionic clathrate hydrates of tetrabutylammonium chloride have been carried out. Structural justification of the occurrence of three different ionic clathrate hydrates derived from tetragonal structure-I in the (C(4)H(9))(4)NCl-H(2)O system has been found for the first time. A novel mode of hydrophilic inclusion of the halide anion with displacement of two hydrogen-bonded host water molecules has been revealed. Structural data obtained are indicative of the possibility of location of tetrabutylammonium cations in combined cavities formed with participation of D-voids.

[On possible influence of different pathways of binding of amides with water on the "pyramidalization" of nitrogen valence bonds of peptide groups].

With the aim to study solvation effects in peptide structure organization, the energy of different types of hydration in simple amines and amides has been analyzed. It was shown based on the quantum-chemical DFT and PM3 calculations of amino derivatives CH3-(CH2)3-NH2, (CH3)2-NH, CH3-NH2, NH3, CH2=CH-NH2, H-CC-NH2, O=C(CH)3-N(CH3)2, O=C(CH3)-NH(CH3), O=C(CH3)-NH2, O=CH-N(CH3)H, and O=CH-NH2 that: (1) in the given set of molecules, the proton acceptor N...H-O variant of hydrogen bonding of NH2-group with a water molecule is dominating only for the simplest amines. Being primordially weaker, the proton donor N-H...OH variant of water H-bonding gradually increases in energy in the given set as the basicity of the compound decreases, and for the case of amides of carbon acids it becomes already a significant channel of the hydration; (2) the intermolecular N-H...O=C bonding of trans-N-methylacetamides, which models the peptide hydrogen bonds in proteins, induces a "planarization" of its initially nonplanar O=C-NH fragments. However, the addition of water molecules to the complex through the proton acceptor N...H-O variant of binding of N atom not only "restores", but even strengthens the "pyramidalization" of valent bonds of peptide groups in this place.

Air detoxification with nanosize TiO2 aerosol tested on mice.

A method for fast air purification using high concentration aerosol of TiO(2) nanoparticles is evaluated in a model chemical catastrophe involving toxic vapors of diisopropyl fluorophosphate (DFP). Mice are used as human model in a closed 100 dm(3) chamber. Exposure of mice to 37 ppm of DFP vapor for 15 min resulted in acute poisoning. Spraying TiO(2) aerosol in 2 min after the start of exposure to DFP vapors resulted in quick removal of DFP vapors from the chamber's air. Animals did not show signs of poisoning after the decontamination experiment and exposure to TiO(2) aerosol alone. Reactive oxygen species (ROS) and antioxidant activity (AOA) of mice blood plasma were measured for animals exposed to sound of aerosol generator, DFP vapors, TiO(2) aerosol and DFP vapors+TiO(2) aerosol. Reduced ROS and increased AOA were found for mice exposure to sound, DFP and TiO(2) aerosol. Exposure to DFP and decontamination with TiO(2) nanoparticles resulted in decreased AOA in 48 h following the exposure. The results suggest that application of TiO(2) aerosol is a powerful method of air purification from toxic hydrolysable compounds with moderate health aftermaths and requires further study and optimization.

Observation of an "ABC" Effect in proton-proton collisions.

The cross section for inclusive multipion production in the pp-->ppX reaction was measured at COSY-ANKE at four beam energies, 0.8, 1.1, 1.4, and 2.0 GeV, for low excitation energy in the final pp system, such that the diproton quasiparticle is in the 1S0 state. At the three higher energies, the missing-mass M_{X} spectra show a strong enhancement at low M_{X}, corresponding to an Abashian-Booth-Crowe effect that moves steadily to larger values as the energy is increased. Despite the missing-mass structure looking very different at 0.8 GeV, the variation with M_{X} and beam energy are consistent with two-pion production being mediated through the excitation of two Delta(1232) isobars, coupled to S and D states of the initial pp system. There is no sign of any resonancelike structure in the energy dependence of the type recently observed for the pn-->dpi;{0}pi;{0} total cross section.

Observation of inverse diproton photodisintegration at intermediate energies.

The fundamental reaction pp-->{pp}_{s}gamma, where {pp}_{s} is a proton pair with low excitation energy, has been observed with the ANKE spectrometer at COSY-Jülich for proton beam energies of T_{p}=0.353, 0.500, and 0.550 GeV. This is equivalent to photodisintegration of a free 1S0 diproton for photon energies E_{gamma} approximately T_{p}/2. The differential cross sections measured for c.m. angles 0 degrees gammad is on the 10;{-3}-10;{-2} level. The increase of the pp-->{pp}_{s}gamma cross section with T_{p} might reflect the influence of the Delta(1232) excitation.

[Clinical variants of Churg-Strauss eosinophilic vasculitis].

The purpose of the study was to analyze clinical variants of eosinophilic vasculitis (EV). The authors observed 12 EV patients (five men and seven women; mean age 43 +/- 5.7) during a ten-year period. Two of the patients died of ventricular fibrillation due to myocarditis and of mesenterial thrombosis. Clinical variants of EV were diverse. The main syndromes in EV were: predominant lesion of the pulmonary system with polyneuropathy; lesion of the gastrointestinal tract (GIT) with eosinophilia; lesion of the cardiovascular system as well as association with other rheumatologic conditions (rheumatoid arthritis and diffuse eosinophilic fasciitis). The main therapeutic regimens in EV include steroidal therapy in medium to large doses, cyclophosphan intramuscularly, and intensive care--pulse therapy with metipred and plasmapheresis. Analysis of the results of the treatment of these patients demonstrated the efficacy of cyclophosphan administered in doses of approximately 2300 mg per course intramuscularly in combination with prednisolone (more than 40 mg a day), plasmapheresis (more than three sessions per a course), antiaggregants, heparin (more than 18000 units a day) and general hyperbaric oxygenation, as well as pulse therapy with metipred in a dose of 2200 mg per three days as intravenous infusion. The prognosis of EV was most poor in cases of lesion of the cardiovascular system and the GIT.

[Helix-forming conformers in structural organization of methylamides of N-acetyl-alpha-L-amino acids. Quantum-chemical study].

Based on the results of quantum-chemical PM3 calculations, some common structural and thermodynamic properties of low-energy monopeptide conformers have been revealed that may be responsible for the initiation of alpha- or beta-like forms in polypeptide structures.

[Torsion lability of the O=C-N-H fragment in single dipeptide molecules of L-amino acids].

On the basis of ab initio MP2 and semi-empirical PM3 quantum-chemical calculations the bistability of the nonplanar O=C-N-H fragment in the structure of simple amides and dipeptides is discussed. The influence of the nature of amino acids on the structural polymorphism of the peptide group in dipeptides is shown.

[The mechanism of accumulation of the large electric dipole moment of DNA molecule. PM3 quantum-chemical analysis].

On the basis of the idea of the intrinsic polymorphism of Watson-Crick base pairing in DNA structure, the process of accumulation of the large electric dipole moment in model spiral stacks of canonical non-planar AT and GC pairs was analyzed using the quantum-chemistry methods. The dependence of the value and orientation of electrical dipole moment of a double helix on spiral length, geometry of base H-pairing, and the bending of the major axis of the helix were considered.

Measurement of the analyzing power in p-->d-->(p p)n with a fast forward 1S0 proton pair.

A measurement of the analyzing power A(y) of the p-->d--> (p p) + n reaction was carried out at the ANKE spectrometer at COSY at beam energies of 0.5 and 0.8 GeV by detection of a fast forward proton pair of small excitation energy E(pp) < 3 MeV. The S-wave dominance in the fast diproton is experimentally demonstrated in this reaction. While at T(p) = 0.8 GeV the measured analyzing power almost vanishes, it rises to nearly unity at T(p) = 0.5 GeV for neutrons emitted at theta(c.m.)(n) = 167 degrees. The results are compared with a model taking into account one-nucleon exchange, single scattering, and Delta(1232) excitation in the intermediate state. The model describes fairly well the unpolarized cross section obtained earlier and the analyzing power at 0.8 GeV; it fails to reproduce A(y) at 0.5 GeV.

Surface field activated fragmentation of arginine oligomers.

Protonated arginine oligomers produced by matrix-assisted laser desorption/ionization (MALDI) graze at a kinetic energy of 350 eV along a surface of fluorinated hydrocarbon or mineral oil. The cation fragments activated by excitation processes during the slide on the surface are analyzed by time-of-flight mass spectrometry. The resulting fragment ion mass spectra are interpreted by applying a theoretical concept of excimol accumulation and trap bond dissociation, suggested earlier. According to this theory, energy is accumulated and fragments are formed independently by each arginine residue of a sliding oligomer ion. It is concluded that the observed variation in the fragment ion spectra of the oligomers is a consequence of different oligomer velocities and not a fingerprint of different ion structures.

a+0 (980)-resonance production in pp-->dK+K-0 reactions close to threshold.

The reaction pp-->dK+K(-)0 has been investigated at an excess energy of Q=46 MeV above the K+K(-)0 threshold with ANKE at the cooler synchrotron COSY-Jülich. From the detected coincident dK(+) pairs, about 1000 events with a missing K(-)0 were identified, corresponding to a total cross section of sigma(pp-->dK+K(-)0)=[38+/-2(stat)+/-14(syst)] nb. Invariant-mass and angular distributions have been jointly analyzed and reveal s-wave dominance between the two kaons, accompanied by a p wave between the deuteron and the kaon system. This is interpreted in terms of a(+)0 (980)-resonance production.

[What does the "screening hypochromism of chromophores" actually imply]. / Chto zhe samom dele oznachaet "ékranirovochnyi gipokhromizm khoromoforov"?

The groundlessness of the conception of "screening hypochromism" from the viewpoint of physics is shown.

[Systemic lupus erythematosus and infectious endocarditis: similarities and differences]. / Sistemnaia krasnaia volchanka i infektsionnyi éndokardit: grani skhodstva i razlichiia.

AIM: To compare clinical laboratory data in systemic lupus erythematosus (SLE) and infectious endocarditis (IE) for analysis of similar and different features. MATERIAL AND METHODS: Clinical and laboratory findings were compared for 72 IE and 71 SLE patients examined for a decade. RESULTS: SLE and IE have the following common features: fever, pleurisy, pericarditis, hemorrhagic vasculitis, articular syndrome, renal disorders, anemia, rheumatoid factor (RF), cryoproteins (CP), elevated ESR, concentrations of circulating immune complexes (CIC), IgM. Characteristic of SLE were skin erythema, alopecia, Raynaud's syndrome, cerebrovasculitis, lymphadenopathy, pneumonitis, frequent articular lesions, leucopenia, high IgG levels, CP and antibodies to DNA. IE was characterized by thromboembolic complications, splenomegaly, pneumonia, high CIC and medium mass molecules concentration, high incidence rate of RF, positive hemoculture. CONCLUSION: In spite of known differences between IE and SLE, in some cases differential diagnosis is not easy to make. This leads to late etiopathogenetic therapy.