Oxidation of Са2+-Binding Domain of NADPH Oxidase 5 (NOX5): Toward Understanding the Mechanism of Inactivation of NOX5 by ROS.

NOX5 protein, one of the most active generators of reactive oxygen species (ROS), plays an important role in many processes, including regulation of cell growth, death and differentiation. Because of its central role in ROS generation, it needs to be tightly regulated to guarantee cellular homeostasis. Contrary to other members of NADPH-oxidases family, NOX5 has its own regulatory calcium-binding domain and thus could be activated directly by calcium ions.

[Left helix of polyproline II type and genesis of beta-structures in spidroins 1 and 2 and their recombinant analogs].

The distribution of secondary structures along the polypeptide chains of spider proteins spidroins 1 and 2 and their recombinant analogs has been studied by statistical methods. It was found that these proteins in the monomolecular form contain only trace amounts of beta-structures. At the same time, the regions of the sequence including Ala and Gly are predicted as helical-containing (with alpha-helices and left-helices of polyproline II type).

Structure of glutamate decarboxylase from E. coli: spectral studies.

Structure of recombinant glutamate decarboxylase (GAD alpha) was studied by optical methods and electron microscopy. The active (pH 4.6) and inert (pH 6.

Does peroxynitrite partition between aqueous and gas phases? Implication for lipid peroxidation.

Relative reactivity of alkane and alkylbenzene oxidation by peroxynitrite has been determined in acidic aqueous solutions. The observed data are explained assuming that the reaction simultaneously proceeds in both the gas and the liquid phases. The selectivity in the gas phase was found to be very similar to that of discrete hydroxyl radicals.

[The effect of ethanol on heat denaturation of pepsinogen].

The effect of ethanol and medium pH on thermodynamic parameters and cooperativity of pepsinogen thermal denaturation have been studied by scanning microcalorimetry. Addition of 20% (v/v) ethanol decreases the protein temperature of denaturation by 10.7 degrees C at pH 6.

[Study of the conformational properties of C-terminal fragments of histones H1, H5, and beta-endorphin by circular dichroism].

Circular dichroism technique has been used for investigating the conformation of histone H1 and H5 C-terminal fragments and beta-endorphin. It has been shown that in aqueous solution these polypeptides adopt preferably the left-handed helical conformation of the poly-L-proline II type. The linear temperature dependence of the CD value during solution heating was found to be broken in the temperature interval between 50 and 55 degrees C.

[The biological indication of the radiation load in forest communities of small mammals].

The content of cesium-137 in the organisms of different species of small mammals in forests of Bryansk Province five years later the Chernobyl accident varies to a great extent within some modal value n.10(-6)-n.10(-7) Cu/kg.

[A study of the conformation of native and immobilized human somatotropin using circular dichroism].

The conformation of human growth hormone (hGH) as monomer and aggregate as well as of those immobilized in the soluble polysaccharide matrix was investigated. The immobilization resulted in ten per cent decrease of the amount of alpha-helix and in the conformational mobility change of aromatic amino acid side groups. It did not, however, influence the biological activity of the hormone, thus suggesting that the above conformational variations did not affect functionally important portions of the molecule.

[The study of actin in denervated skeletal muscles by microcalorimetry].

Method of scanning calorimetry of intact and denervated F-actin shows a change in thermostability of protein after denervation.

[Action of khanerol on the superhelical DNA structure of S-37 cells].

The damaging effects on the structure of a supramolecular DNA complex of sarcoma-37 cells in mice following the use of the therapeutic doses of khanerol were found. Capillary elastoviscosimetry and nucleoid sedimentation procedure showed that the damage of the supramolecular DNA complex structure becomes apparent already after 4 hours, and increases by 24 hour. In studies of the binding of khanerol with DNA by Cd and Tmelt.

[Circular dichroism of actin from denervated skeletal muscles].

Method of circular dichroism did not indicate any changes of the secondary structure of globular and fibrillar actin from denervated skeletal muscles. The matter that some conformational changes of the aromatic residues do in fact accompany denervation was confirmed by fluorescence studies but not by CD spectra.

[Detection of vibron phenylalanine bands in circular dichroism spectra for collagen].

For the first time the individual positive circular dichroism peaks at 268 nm, 262 nm and 256 nm have been found for collagen. These peaks are due to the vibronic nature of a weak pi-pi* phenylic chromophore transition of phenylalanine and the unique structural organization of collagen where water molecules are an essential element of the triple helix.

[A test for the structure of the left helix of poly-L-proline type II in peptides].

The spectral criterion of a left-handed helix of the poly-L-proline II type was elaborated during the study of a number of synthesized oligopeptides (in a solid state and solution): (Gly-Pro-Pro)1-8, (Gly-Pro)1, (Gly-Pro-Ala)1-4, (Gly-Pro-Gly)1-4, (Gly-Pro-Pro) X (Gly-Pro-Gly)1-2(Gly-Pro-Pro), (Gly-Pro-Pro)n, (Orn3-Gly)n and also rat skin collagen by X-ray diffraction, circular dichroism and infrared spectroscopy methods; the characteristic shape of the left-handed helix CD spectrum was found. The change of spectral characteristics with the change of left-handed helix distortion was established. The linear noncooperative melting process of the left-handed conformation was demonstrated.

[Reversal of B to A transition in DNA by bis-(20guanidoethyl)disulfide].

Transition from B to A form of DNA in water/ethanol solutions is hindered by stoichiometric quantities of a bifunctional cation, bis-(2-guanidoethyl)disulfide (GED). Using the data on the shift and widening of the B--A transition curves in the presence of GED, a value of the order of 10 base pairs has been estimated for the cooperativity length of the B--A transition which agrees well with the values earlier obtained.

[Secondary structure of polypeptide hormones of the anterior lobe of the pituitary gland].

The specificity of the secondary structure of a number of polypeptide hormones of the pituitary gland anterior lobe and their fragments were studied by circular dichroism method in the peptide bond absorption region and infrared spectroscopy. The state of objects had been examined in solvents of different polarity in a wide temperature range. The polypeptide chain of a greater part of hormones in aqueous solution is shown to represent a left-handed helix of the poly-L-proline II type.

Warble flies (Hypodermatidae, Oestridae) of some wild animals from Mongolia and Tuva.

Three species of warble flies Pallasiomyia antilopum, Oestromyia leporina and Cephalopina titilator from four species of wild animals were found. Hitherto unknown larva of the first instar of Pallasiomyia antilopum (Pallas, 1771) collected from the saiga (Saiga tatarica L.) is described.

[Bis-(2-guanidoethyl)-disulfide, when complexed with DNA, prevents its winding within the B-family].

Earlier we have shown that DNA forms stoichiometric complexes with bis-(2-guanidoethyl)-disulfide (GED), the helix being transformed from the B-like structure into the C-like one. The present work demonstrates that the DNA helix in the saturated complex does not change its conformation within a broad range of conditions: 0 less than [NaCl] less than 5.10(-2) M; 0% less than [methanol] less than 60% (v/v); 5 degrees less than temperature less than 50 degrees.

[Structure of histone fragments and their models. I. Structural features of N-terminal oligopeptides of histone H4].

Circular dichroism (CD) and infrared spectroscopy (IRS) studies of aqueous solutions of fourth N-terminal peptides of histone H4 with different chain length were carried out under various conditions. It was shown that all studied peptides had conformation of extended left-handed helix as well as poly-1-proline II at the acidic and neutral pH, in moderate ionic strength (0,15), in 80% ethanol, 0,2 M sodium dodecylsulphate, in 8 M urea and 5 M guanidinum hydrochloride. This conformation was changed by raising temperature, under transition to the range of basic pH and in the concentrated solutions of CaCl2 (5M).

[Peculiarities of DNA winding with bifunctional cations].

Addition of the bifunctional cations, bis(2-aminoethyl) disulphide-cystamine, and bis(2-guanidoethyl) disulphide-GED, into water solution of DNA results in a decrease in magnitude of the positive circular dichroism (CD) band. However, unlike the similar effect due to alcaline ions or ions of ammonium and guanidinium the above effect occurs at much smaller, stoichiometric with phosphates, concentrations of the dications. Another peculiarity of GED is the attaining of a plato region for the curve of the CD change with the rise of GED concentration.