Том 44, № 6 (2018)

Nicotinic acetylcholine receptors (nAChRs) are the ligand-gated ion channels important for intercellular signaling. These receptors are abundant in neuromuscular junctions, presynaptic and postsynaptic neuronal membranes in the central and peripheral nervous systems. The nAChR dysfunction is associated with a number of neurodegenerative and muscular diseases. The actual information on the structure and function of these receptors is reviewed in this article.

Cysteine proteases, caspases, play an important role in the process of programmed cell death. In apoptosis, the cell signaling pathways overlap at executioner caspases regardless of the initial stimulus. Caspase-3 is the key one. This review considers the sensors for activity of caspase-3 and some other caspases. Over the past decade, many such sensors utilizing a variety of detection principles have been created; fluorescence and luminescence are the most common detection methods. The intracellular sensors are of particular interest; they allow visualization of the activation of caspases in living systems. Herein, we briefly describe sensors of various designs, the advantages and disadvantages of which must be taken into account when choosing a sensor for a particular experimental system.

The growing problem of antibiotic resistance in medicine is focusing attention on antimicrobial compounds targeting non-protein molecules, which have more conserved structures compared to proteins or peptides. One of the most promising and studied targets is lipid II—the bacterial cell wall biosynthetic pathway principal compound. Lipid II is unique for the bacterial membrane only and has a conserved chemical structure. There are several classes of natural antibiotics targeting lipid II, some of which block peptidoglycan synthesis by formation of a strong complex with lipid II; others have an additional bactericidal mechanism involving disruption of the membrane integrity. This review examines the prospects of using such antibacterial substances as new drugs to combat antibiotic-resistant pathogens. The main emphasis is on the studies of the membrane-embedded lipid II structure and how water-soluble antibiotics recognize its molecular structure, as well as on computer modeling of their interaction.

We performed a computer search for the DSIP homologous structures in the protein data bases and found the KND peptide (WKGGDNASGE), which was closely structurally related to DSIP, corresponding to the 324–332 fragment of the human lysine-specific histone demethylase 3B (EC 1.14.11), and possibly was a prototype of the real endogenous DSIP. Previously, we compared some biological effects of DSIP and KND. Antioxidant, anticonvulsant, and behavioral effects of KND proved to be more pronounced than those of DSIP, suggesting the higher efficacy and therapeutic potential of KND and its derivatives. In this study, we synthesized new analogs of DSIP and KND and examined their detoxifying action after the treatment with the cisplatin cytostatin in comparative experiments in vivo on rodents. KND and several its analogs were found to decrease the cisplatin effects on the induced changes in masses of target organs. The correcting effects of the studied peptides on the cisplatin-induced hematological abnormalities, such as the changes in the leukocyte content in blood and thrombocytopenia, were revealed after their intranasal administration to animals in low doses. A decrease in a pronouncement of histological deviation from a norm was shown in the tissues of liver, kidney, and spleen. A significant hepatoprotective and nephroprotective effects of the studied peptides were also observed. Thus, the revealed antitoxic properties of DSIP, KND, and their analogs, could be a basis for the creation of drugs of lower toxicity in the anticancer treatment and therapy of medicinal hepatitis.

From the Bacillus species D6 strain, the restriction endonuclease BspD6II has been isolated and characterized. It recognizes the asymmetric region 5′-CTGAAG-3′/3′-GACTTC-5′ in the double-stranded DNA. The sites of DNA hydrolysis by this enzyme have been determined. They are localized beyond the recognition site 16 nt downstream of the sequence 5′-CTGAAG-3′ toward the 3′-end of DNA and 14 nt toward the 5′-end in the opposite strand. It has been shown that BspD6II differs in properties from isoschizomer enzymes Eco57I (prototype), AcuI, and BspKT5I and has some advantages. It catalyzes the exhaustive hydrolysis of DNA in the absence of S-adenosyl-L-methionine and effectively operates at 50°C, i.e., is a thermophilic enzyme.

A novel approach to the synthesis of α-amino-ω-nucleo carboxylic acids, analogs of willardiin, an activator of the receptor of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid, which is responsible for the transfer of a fast stimulating signal in the synapses of the nervous system of vertebrates, is proposed. Based on substantial differences in the reactivity of halogen atoms in α,ω-dihalogen carboxylic acids, the esters of α-phthaloylimido-ω-chloro carboxylic acids have been synthesized. The alkylation of uracil, thymine, and adenine with these esters gave the key compounds, the esters of α-phthaloylimido-ω-nucleo carboxylic acids. The consecutive removal of the phthalyl protective group and acid hydrolysis led to new polymethylene derivatives of nucleic bases, which are α-amino-ω-nucleo carboxylic acids. The physical and chemical properties of these compounds were studied.

Photodynamic therapy (PDT) is a clinically approved, minimally invasive method for tumor destruction in the presence of a photosensitizer (PS), oxygen, and a light source. The main obstacle for the PDT treatment of deep tumors is the problem of the excitation light delivery inside the body without reduction of light intensity. An internal light source based on a bioluminescence system NanoLuc-furimazine can be considered as an alternative to an external light source. This system can be successfully used to excite a protein photosensitizer miniSOG and induce its phototoxicity in cancer cells as a result of bioluminescent resonance energy transfer. In this paper, the effectiveness of bioluminescent resonance energy transfer in the NanoLuc-miniSOG-furimazine system in living cells was studied. The efficiency of the energy transfer in this system was found to be independent of the furimazine concentration, while intracellular localization of the NanoLuc-miniSOG hybrid protein was found to be a crucial factor.

New derivatives of isobornylphenols containing a sulfur atom in the para-position in various functional groups have been synthesized. The evaluation of antiradical and antioxidant properties using various model systems has been carried out. The study has shown that compounds with a sulfhydryl group display the most antioxidant activity, which is determined by the presence of two reaction centers. It has been noticed that a number of terpenic substitutes in ortho-positions of the phenol molecule as well as the length of spacer between the aromatic nucleus and the functional group affect the activity. 2,6-Diisobornyl-4-sulfanylphenol (in low concentration exceeding the highly effective antioxidant 2,6-diisobornyl-4-methylphenol) shows considerable promise for investigating pharmacological activity.

An electrophile, 2-bromo-N-(5-methyl-1,3-thiazol-2-yl)acetamide, was synthesized by the reaction of 5-methyl-1,3-thiazol-2-amine and bromoacetyl bromide in an aqueous medium. In a parallel scheme, a series of (un)substituted benzoic acids was converted sequentially into respective esters, acid hydrazides, and then into 1,3,4-oxadiazole heterocyclic cores. The electrophile was coupled with the aforementioned 1,3,4-oxadiazoles to obtain the targeted bi-heterocyles. Structural analysis of the synthesized compounds was performed by IR, EI-MS, ¹H NMR, and ¹³C NMR. The enzyme inhibition study of these molecules was carried out against four enzymes, namely, acetylcholinesterase, butyrylcholinesterase, α-glucosidase, and urease. The interactions of these compounds with respective enzymes were recognized by their in silico study. Moreover, their cytotoxicity was also determined to find out their utility as possible therapeutic agents.

The activity of specific tyrosine protein kinases is known to be associated with the production of oncogenes. A specific inhibitor of tyrosine protein kinases can be effective not only as an antitumor agent but also as a tool for studying the physiological role of tyrosine phosphorylation. Among similar inhibitors, the flavonoid genistein was shown to have the most specific effect. This agent almost completely inhibited phosphorylation of tyrosine residues, while the activity of serine and threonine protein kinases was slightly suppressed. At the same time, another flavonoid quercetin inhibited activities of tyrosine kinase and other protein kinases with equal efficacy. The aim of the work was to study the effect of genistein on phosphorylation of maize mitochondrial proteins at the tyrosine residues for the assessment of signal cascades associated with tyrosine protein kinases. It was first revealed that tyrosine phosphorylation occurred in the maize mitochondrial heat shock protein 60 (HSP60) and the protein of 90 kDa. Phosphorylation of the 90-kDa protein is observed only during the treatment of isolated mitochondria with genistein. The study of the activity of mitochondrial respiratory complex V showed a significant decrease in the hydrolytic activity of the mitochondrial ATPase after exposure to genistein. The activating effect of this agent on mitochondrial protein kinases can be explained by changes in the redox state of mitochondria due to inhibition of mitochondrial ATPase by genistein.

The rapid development of lipidomics of human and higher animals stimulated the study of the lipidome of certain groups of marine organisms. Soft corals are an integral part of the tropical and cold-water ecosystems of the World Ocean, but there is almost no data on the lipidome of these animals. The total lipidome of a tropical soft coral Sinularia siaesensis (Cnidaria: Anthozoa: Octocorallia: Alcionacea) containing intracellular symbiotic microalgae (zooxanthellae) was studied by gas and liquid chromatography-mass spectrometry. The structure and content of 144 molecular species of the main classes of acyl lipids of this alcyonaria were determined, including waxes, triglycerides (TG), monoalkyldiacylglycerides (MADAG), ethanolamine, choline, serine, and inositol glycerophospholipids (PE, PC, PS, and PI), ceramide aminoethylphosphonate (CAEP), sulfoquinovosyldiacylglyceride (SQDG), and mono- and digalactosyldiacylglycerides (MGDG and DGDG). The main components of S. siaesensis lipids were waxes 16:0/16:0, 16:0/18:0, and 18:0/16:0; TG 16:0/16:0/16:0 and 16:2/16:0/16:0; MADAG 18:0e/16:0/16:0, 16:0e/16:0/18:0, and 16:0e/16:0/16:0; and PS 18:0e/24:5, lyso-PC 18:0e, PE 18:1e/20:4, PC 18:0e/20:4, CAEP 18:2b/16:0, SQDG 14:0/16:0, and PI 18:0/24:5. The dominance of saturated waxes in reserve lipids is a species-specific feature of tropical alcyonarians. Waxes are synthesized in the host organism, and zooxanthellae can increase the proportion of saturated waxes by transferring saturated fatty acids (FA). The residues of polyunsaturated FA (PUFA) are found in the molecules of TG and MADAG, mainly in the sn-1 and sn-2 positions, respectively. Detection of MADAG with residues of marker FA of zooxanthellae (18:0e/18:3/16:0, 18:0e/18:4/16:0, and 16:0e/18:3/16:0) confirms the transfer of PUFA from the symbionts to the host. Tetracosapolyenoic FA, which is a chemotaxonomic markers of octocorals, are concentrated in molecular species of PS and PI. Most molecular species of PE, PC, and PS are in alkylacyl form, while for PI molecules, a diacyl form is characteristic. A significant proportion of MGDG, DGDG, and SQDG points to the importance of zooxanthellae in the formation of the lipid profile of symbiotic soft corals. Determination of the profile of lipid molecular species requires the development of a lipidomic approach in the study of biochemistry and ecology of corals and other cnidarians.

Preparation of liposomal formulations containing water-soluble drugs in the form of lipophilic prodrugs in their lipid bilayer is of considerable interest. Previously, we synthesized doxorubicin dioleoyl glyceride and oleoyl conjugates intended for incorporation into fluid-phase liposomal bilayers. In this work, we studied the behavior of lipid conjugates in bilayers prepared from palmitoyl oleoyl phosphatidylcholine and dimyristoyl phosphatidylcholine using methods of fluorescence spectroscopy and molecular modeling. The conjugates were shown to have limited mobility in lipid bilayers, which can be explained by the formation of hydrogen bonds between the doxorubicin aglycone and the lipid phosphate groups. In the liposome membrane, lipophilic conjugates also tend to form clusters through interaction of doxorubicin moieties. Oleoyl chains stretch in parallel to the acyl residues of phospholipids. Due to the formation of a larger number of hydrogen bonds, the oleoyl conjugates interacted with the bilayer more effectively than the dioleoyl glyceride counterparts. These properties of doxorubicin conjugates can affect both the possibility of their incorporation into the lipid bilayer (from the therapeutic effect point of view) and intracellular release of the antibiotic drug by means of enzymolysis.

The aim of this work was to identify the spectrum of possible protein-protein interactions (PPI) for six target proteins (CYB5A, RAB27B, SMAD4, CXXC1, RNMT, ТТR) encoded by genes of human chromosome 18, which have a certain medical significance. For this purpose, a comprehensive approach based on the combined application of three technologies, direct molecular fishing based on affinity chromatography, protein mass spectrometry and SPR (surface plasmon resonance) analysis, was used. As a result, from 1 to 11 potential protein partners were isolated from the lysate of the human hepatocellular carcinoma HepG2 cell line for each target protein. Using the Biacore 3000 SPR biosensor, 10 potential PPIs, for which preparations of recombinant proteins were available, were validated. Positive results, which confirm direct interaction of the identified protein partners with target proteins, were obtained for five protein pairs (СYB5A/CPR, СYB5A/CYP2C9, СYB5A/CYCS, CPR/СYP2C9 and CXXC1/CYCS). The values of equilibrium dissociation constants of protein complexes (K_d values ranged from 10^–7 M to 10^–5 M) were determined for these PPIs. To evaluate the specificity of identified PPIs, 16 additional different PPIs of the target proteins were tested. The effectiveness of direct molecular fishing was evaluated using cytochrome b₅ (CYB5A) as the most studied target protein in the context of structural and functional relationships with its protein partners. The new data extend our knowledge in the field of interactomics of proteins encoded by human chromosome 18 genes and reduces the number of unverified bioinformatic predictions of possible PPIs presented in accessible Internet resources.