[Synthetic proteins with antiviral properties of alpha-interferons].

Consensus sequence 30-36 LKDRHDF of human alpha-interferons is inserted into the C- and N-terminal sequences of the artificial protein albeferon using genetic engineering methods in order to obtain artificial proteins with antiviral activity. Albeferon, obtained by Dolgikh et al. (Protein Eng.

[Interaction of synthetic decapeptide SLTCLVKGFY with human T lymphocytes].

The synthetic peptide SLTCLVKGFY, corresponding to the 364-373 amino acid sequence of the human IgG heavy chain (Immunorphin), was found to compete with [125I] beta-endorphin for binding by high-affinity receptors on T lymphocytes isolated from the blood of healthy donors (Ki 0.6 nM). The fragments 3-10, 4-10, 5-10, and 6-10 of Immunorphin also inhibited the binding (Ki 2.

[Hormone-like activity of a synthetic decapeptide with the adrenocorticotropin-like sequence of human immunoglobulin G1].

The antiproliferative and immunosuppressive in vitro effects of immunocortin, a synthetic adrenocorticotropin-like (ACTH-like) decapeptide H-Val-Lys-Lys-Pro-Gly-Ser-Ser-Val-Lys-Val-OH, whose sequence corresponds to segment 11-20 of the variable part of the human IgG1 heavy chain, were studied. At concentrations of 10(-11)-10(-7) M, immunocortin was found to inhibit the growth of the human MT-4 T-lymphoblastoid cell line, to suppress the blast transformation of thymocytes, and to decrease the spontaneous mobility of peritoneal macrophages and their bactericidal action toward the virulent strain Salmonella typhimurium 415. By using a 125I-labeled "addressing" fragment of ACTH ¿[125I]ACTH-(13-24)¿, we showed that MT-4 cells express specific receptors for ACTH (Kd 97 pM).

[Effect of L-glutamic acid on the reception of cytokines by HL-60 cells].

L-Glutamic acid at a concentration of 0.1 microM was found to induce differentiation of the cell line of HL-60 promyelocytic leukemia into granulocytes or neutrophils. The HL-60 cells have no specific glutamate-binding sites, but L-glutamic acid influences the reception of several cytokines by these cells.

[Interaction of L-glutamic acid with human T-lymphocytes].

A specific interaction of [3H]Glu with T lymphocytes from the blood of healthy donors (Kd = 0.236 microM) was revealed and described. It was found that unlabeled quisqualate, a structural analogue of L-glutamic acid, and unlabeled dipeptides Ala-Glu, Glu-Ala, and Glu-Glu competitively inhibit the specific binding of [3H]Glu to T lymphocytes (with Ki 0.

[1H-NMR studies of the ACTH-like immunoregulatory peptides].

A comparative study of the conformational and dynamics properties of the ACTH-like linear peptides, sequences of which correspond to amino acid residues 11-20 of the heavy chain of human immunoglobulin G1 Eu, residues 78-85 of human pro-interleukin-1 alpha and site 10-18 of human ACTH, was performed in aqueous solution and dimethylsulfoxide by 1H-NMR spectroscopy at 400 MHz. The peptides were shown to possess an unordered unfolded flexible conformation in aqueous solution. The revealed structural and dynamic features of the peptides are discussed together with biological activity of this class of compounds.

[1H-NMR study of immunoregulatory peptides].

Conformational and dynamic properties of the synthetic peptides, amino acid sequence of which correspond to biologically active fragments of the following human cytokines: alpha 2, gamma interferons and interleukins 1 beta, 2, were studied in aqueous solution and dimethylsulfoxide by one-dimensional and two-dimensional 1H-NMR spectroscopy (400 MHz). The analysis of nuclear Overhauser effect data, values of vicinal J3(NH-C alpha H) coupling constants of amide protons and their temperature coefficients of chemical shifts indicate an unordered flexible conformation of the peptides in aqueous solutions. The structural and dynamic features of the peptides investigated are discussed together with their biological activity.

[Europium-labelled Staphylococcus aureus protein A as a reagent for determining specific antibodies].

In this work the conditions of labeling protein A with europium ions were studied and the conjugates obtained in this study were compared with traditional peroxidase conjugates currently used in immunochemistry. The conjugates of protein A with Eu3+ chelate were obtained with the use of cyclic dianhydride of diethylenetriaminepentaacetic acid (DADETPA). Conjugation methods with the use of DADETPA was shown to permit obtaining high-quality conjugates with europium chelates.

[The structural and functional classification and evolution of cytokines].

According to the type of secondary structure, cytokines are classified into three categories: alpha-spiral (IFNs-alpha, beta, omega, gamma; ILS-2, 3,4,5,6,7,9; CSFs-G, M, GM, MGF, PDGF), beta-structural (ILs-1 alpha, beta, TNFs-alpha, beta, FGF) and (alpha + beta)-structural proteins (IL-8, IFN-gamma IP-10, PF-4, bTG, GRO, 9E3). According to the type of tertiary structure, alpha-spiral proteins are grouped into IFN- and IL-2-like families and beta-structural ones into IL-1-, and TNF-like families. Two subfamilies can be identified in the IFN-like family.

[Study of the structural properties of recombinant gamma-interferon by circular dichroism and differential scanning microcalorimetry].

Recombinant human gamma-interferon is dimeric in solution at pH 7-4 as revealed by analytical gel-filtration. It was shown by circular dichroism that decreasing pH to 5.0 does not affect the secondary and tertiary structures of gamma-interferon macromolecule.

[Study of the structural properties of recombinant leukocyte interferon A by means of fluorescence polarization, circular dichroism, and differential microcalorimetry].

Human leukocyte interferon-A1 (IFN-alpha A) structure in solution was investigated by fluorescence polarization, circular dichroism and scanning microcalorimetry techniques. Using gel-filtration it was established that at neutral pH values and at concentration not exceeding 0.3 mg/ml IFN-alpha A has a dimeric configuration in solution.

[Study of the structural-functional properties of immunoglobulins G and their fragments using 1H-NMR].

Data on NMR-spectroscopy studies of the structure-function interrelation in immunoglobulins G and their proteolytic fragments are reviewed. Relationship between structural and dynamic characteristics of immunoglobulins G and their functional properties is discussed.

[Manifestations of domain organization of the Staphylococcus aureus protein A during heat denaturation of its structure].

Melting of protein A from Staphylococcus aureus has been studied in neutral medium by the methods of microcalorimetry and circular dichroism. The melting process of protein A is shown to consist of, at least, 5 independent transitions. The transition with the heat absorption maximum at 38 degrees is ascribed to the melting of the C-terminal domain of protein A.

[The role of the immunoglobin G "hinge" region in heat aggregation and activation of complex-formation].

A high degree of correlation between the capability of subclasses of human immunoglobulins G to form aggregates due to thermal treatment, and their complement-binding activity was established. On the basis of the experimental data obtained by the methods of light scattering, circular dichroism, microcalorimetry, it was supposed that "hinge" region of immunoglobulins G participates in the initial stage of thermal aggregation and in the activation of the process of complement binding.

[Comparative study of conformation properties of Fc-fragments of human immunoglobulin G subclasses using 1H-NMR].

Conformational properties of the Fc- and pFc'-fragments of human myeloma immunoglobulins G of the first and third subclasses were studied by 1H-NMR method (270 and 400 MHz). It was found that the globular structures (domains) of the Fc-fragments of IgG1 and IgG3 in solution are characterized by high segmental mobility, and have no significant differences in their spatial arrangement. Comparative analysis of the spectra obtained at different temperatures (30-70 degrees C) revealed that the Fc-fragment of IgG3 has a more heat-stable conformation than the Fc of IgG1.

[1H-NMR study of the peptide corresponding to the ACTH-like sequence of the variable region of human G1 Eu heavy chain immunoglobin].

Synthetic decapeptide corresponding to ACTH-like sequence of the variable part of the heavy chain of immunoglobulin G1 Eu was studied by two-dimensional 1H-NMR spectroscopy (400 MHz). A complete assignment of signals in the peptide spectrum was made. The decapeptide was shown not to have any ordered spatial structure, and was characterized by a high extent of flexibility of the oligopeptide chain, except for the peptide bond with an N-terminal residue.

[The role of intermolecular electrostatic cooperative interactions causing cryoprecipitation of human monoclonal immunoglobin M].

A chemical modification of carboxylic groups of monoclonal human cryoglobulin M has been studied. The modification by a chromophoric carbodiimide was accompanied by complete loss of IgM cryoprecipitating properties. The number of carboxylic groups important for biological activity was estimated by the Tsou method and found to be 2.

[Theoretical and experimental studies on the conformation of the hinge regions in human immunoglobulin G subclasses].

Using the methods of difference adiabatic scanning microcalorimetry and difference thermal perturbation spectrophotometry it was established that both the Fc subunits within the intact immunoglobulins G of different subclasses, and the Fc fragments corresponding to them significantly differ in conformational properties. These differences are associated with a different energy of interactions between the CH2 and CH3 domains and also with a different rigidity of structure of the N- and C-terminal parts of the CH2 domains. The analysis of these data allowed to suggest that the "hinge region" interacts with the CH2 domains and the difference in the structure of this region affect the conformation of the Fc subunits.

[Comparative investigation of the dynamic conformational properties of human myeloma immunoglobulin G of different subclasses using impulse NMR].

The evidence of the intramolecular flexibility of human myeloma immunoglobulin G belonging to the second, third and fourth subclasses has been obtained using the impulse NMR method. It has been found that the degree of intramolecular flexibility for the myeloma immunoglobulin G belonging to the first subclass decreases significantly by cooling from 37 to 10 degrees.