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Тек жазылушылар үшін
Том 90, № 9 (2025)
Articles
MEMBRANE GUANYLATE CYCLASES AS POTENTIAL TARGETS OF GUANYLINS
Аннотация
Guanylins are intestinal natriuretic peptides that regulate water-salt balance at the level of the intestine and kidney. The main receptor through which guanylin peptides influence electrolyte balance is membrane guanylate cyclase C. Alternative functions related to food behavior and olfactory preferences are implemented by guanylins through guanylate cyclase D, expressed exclusively in olfactory neurons. At the same time, there is the evidence for alternative yet undefined "natriuretic" receptors activated by guanylin peptides in the absence of guanylate cyclase C. Among these receptors, there are those that trigger a cGMP-dependent signaling pathway that is specific to guanylate cyclases. This review provides a comparative analysis of existing data on different membrane guanylate cyclases, including both early discoveries and modern studies, with an emphasis on considering different types of membrane guanylate cyclases as potential targets of guanylins' action.
Biochemistry. 2025;90(9):1247-1267
1247-1267
CHEMISTRY OF THE JOINT ORIGIN AND EVOLUTION OF LIFE, DEATH, AND AGING
Аннотация
Reviewing the published insights concerning chemical interactions between small molecules implicated in the origin of life suggests that their chemical properties included not only those that may be suitable for metabolic pathways. Some of the immanent “excessive” potencies of the molecules make them able to form covalent adducts to proteins and nucleic acids. The accumulation of macromolecules damaged in this way could decrease protocells viability with increasing age. Thus, aging (senescence) could emerge concomitantly with life as its chemical heritage. Moreover, the exponential increase in mortality with age (the Gompertz law) could emerge when the kinetics of molecular disintegration according to the Arrhenius equation (disintegration rate depends exponentially on varying temperature at a constant activation barrier) was inherited by the kinetics of protocells dying out in their populations, the role of the independent variable having passed from temperature, which was virtually constant on the Calvin scale, to viability. The cooperation of these two chemical heritages was enough to eliminate effectively old living objects and to make any evolved program of aging needless. Thus, aging did not result from the biological evolution but rather was and still is its independent factor. All this was possible without oxygen, which could only modify rather than form de novo the primary chemical driving force of aging. With all that, the energetic benefits of aerobic metabolism provided for the advent of multicellular organisms, in particular those featuring massive extracellular matter and unrenewable cell populations, including those comprising the brain. Their functions are incompatible with complete renewal. This makes oxygen’s role in aging not limited to being the source of the reactive oxygen species. Oxygen was indispensable for the advent of both the accumulators of chemical damage and the ability to recognize it. In a sense, for nature it was not a problem to develop aging in the course of evolution towards humans for whom being aware of aging is a problem. Its satisfactory solution cannot be chemical, physical, pharmacological or otherwise technical. It can be only mental.
Biochemistry. 2025;90(9):1268-1296
1268-1296
IP3 RECEPTORS MEDIATE CALCIUM AND ANABOLIC SIGNALING ASSOCIATED WITH MUSCLE ATROPHY UPON 3-DAY HIND LIMB UNLOADING IN RATS
Аннотация
Skeletal muscle unloading results in muscle atrophy associated with the upregulation of proteolytic genes and suppression of protein synthesis, often accompanied by altered calcium signaling. Here, we used the inositol trisphosphate receptor (IP3R) inhibitor aminoethoxydiphenyl borate (2-APB) to explore the hypothesis that these changes are mediated by IP3Rs. Male Wistar rats were divided into 4 groups: (i) control, (ii) control with daily injections of 2-APB; (iii) 3 days of hind limb suspension, (iv) 3 days of hind limb suspension with daily administration of 2-APB. At the end-point, soleus muscles from the animals were analyzed by Western blotting for the markers of calcium, anabolic, and catabolic signaling. The 3-day hind limb unloading resulted in a decreased muscle weight index, upregulation of the anabolic suppressor pThr56-eEF2, downregulation of anabolic signaling via the mTOR pathway and rRNA expression, as well as the increase in the content of nuclear pThr286-CaMKII (p < 0.05) and cytosolic calcineurin A. While 2-APB did not affect the mTOR-governed changes in anabolism and catabolism, it significantly attenuated alterations in the calcium-dependent targets, such as CaMKII, calcineurin, and eEF2. By contrast, proteolytic signaling (expression of MuRF1, atrogin-1, Ulk-1, and ubiquitin mRNAs) after 3-day hind limb unloading was equally upregulated in the control and 2-APB-treated animals. These results suggest that IP3Rs are involved in the unloading-induced muscle atrophy by controlling the nuclear content of calcium; however, they are dispensable for reduced mTOR activity and altered metabolism.
Biochemistry. 2025;90(9):1297-1310
1297-1310
ION TRANSPORTERS GENE EXPRESSION IN GILLS AND INTESTINE OF MALE AND FEMALE THREESPINED STICKLEBACKS DURING FRESHWATER ADAPTATION
Аннотация
In euryhaline fish species, including the three-spined stickleback, a key physiological response to freshwater adaptation aimed at maintaining osmotic homeostasis is the enhancement of ion uptake from the environment and the reduction of ion loss. The hormone prolactin, a central regulator of this process, primarily targets the gills and intestine. Our previous work demonstrated that, in a model of freshwater adaptation in sticklebacks, prolactin expression and the sensitivity of osmoregulatory tissues to prolactin differ between males and females. In the present study, we measured the expression levels of genes encoding the α1a and α3a subunits of Na+/K+-ATPase, as well as ion transporters NKCC1a, NKCC2, NCC, and NHE2, in the gill and intestinal tissues of male and female three-spined sticklebacks (Gasterosteus aculeatus L.) under conditions of acute (24 h) and chronic (72 h) freshwater adaptation, relative to control conditions. During freshwater adaptation, females – but not males – exhibited increased intestinal expression of nhe2 and atp1a3 (as well as the atp1a1/atp1a3 expression ratio), and nkcc1a, along with decreased expression of nkcc2. In contrast, only males showed an increase in ncc expression in the intestine. In both sexes, freshwater exposure led to a significant decrease in nkcc1a expression in the gills. These findings support our hypothesis of sex-dependent plasticity in osmoregulatory function in sticklebacks, with females exhibiting a more pronounced response. This pattern further aligns with previously reported stronger activation of the prolactin axis in females under freshwater adaptation conditions.
Biochemistry. 2025;90(9):1311-1324
1311-1324
APPROACHES TO HUMANIZATION OF MITOCHONDRIAL PROTEINS IN Saccharomyces cerevisiae ON THE EXAMPLE OF REPLACING THE YEAST MITOCHONDRIAL TRANSLATION TERMINATION FACTOR MRF1 WITH ITS HUMAN HOMOLOGS
Аннотация
Mitochondrial translation is a highly specialized process of synthesizing mitochondrically encoded proteins, mainly the components of the oxidative phosphorylation system. It involves four key stages: initiation, elongation, termination, and recycling of mitochondrial ribosomes. Each of these stages is regulated by a specific set of translation factors, most of which are encoded by the nuclear genome and imported into mitochondria. The termination of mitochondrial translation in yeast (Saccharomyces cerevisiae) is carried out by the MRF1 release factor. This nuclear-encoded factor is crucial for ensuring accurate protein synthesis within the organelle, as it recognizes stop codons and facilitates the release of completed polypeptide chains from the ribosome. In addition to its main function, MRF1 participates in maintaining mitochondrial genome stability. The aim of this study was to investigate the capacity of human homologs, hMTRF1, hMTRF1A, and mitoribosome rescue factors hMTRFR and hMRPL58, to compensate for the absence of the yeast mitochondrial translation termination factor MRF1 in S. cerevisiae cells. The results obtained suggest that human orthologs of MRF1, such as hMTRF1 and hMTRF1A, can contribute to maintaining the integrity of yeast mitochondrial genome. However, they do not fully make up for the absence of MRF1, as they do not restore normal respiration of the mutant yeast strains.
Biochemistry. 2025;90(9):1325-1337
1325-1337
EFFECT OF NON-MUSCLE TROPOMYOSIN ISOFORMS ENCODED BY THE TPM1 GENE ON COFILIN-1 ACTIVITY TOWARD ACTIN FILAMENTS
Аннотация
The actin cytoskeleton is an integral participant in a large number of cellular processes, such as organelle transport, motility, contractility, exocytosis and endocytosis. At the same time, it plays an important role in pathological processes, for example, malignant invasion of cancer cells. Actin-binding proteins, in particular proteins of the tropomyosin family (Tpm) and cofilins, participate in the remodeling of the actin cytoskeleton. For the study, we selected the least studied Tpm isoforms expressed from the TPM1 gene – Tpm1.7, Tpm1.8, and Tpm1.9 – as well as the more well-known Tpm1.1 and Tpm1.6. In this work, we studied the mutual influence of these Tpm isoforms and cofilin-1 (cof-1) on the dynamics of the actin cytoskeleton. Using the method of co-precipitation of these proteins, it was shown that Tpm1.7, Tpm1.8 and Tpm1.9 isoforms significantly interfere with cof-1 binding to the F-actin surface. Viscometry was used to evaluate the depolymerizing and severing effect of cof-1 on actin filament. Isoforms Tpm1.1, Tpm1.8, and Tpm1.6 effectively prevented the depolymerizing/severing effect of cof-1, while the protective effect of Tpm1.7 and Tpm1.9 was less pronounced. The rhodamine-phalloidin release assay was used to analyze conformational changes in F-actin induced by cof-1. All studied Tpm isoforms effectively prevented the effect of cof-1 on actin filament. The study showed that TPM1 gene products generally have an inhibitory effect on cof-1 activity in relation to the dynamics of actin filament polymerization/depolymerization. Such properties of Tpm isoforms may be important for the formation of specific intracellular populations of actin filaments.
Biochemistry. 2025;90(9):1338-1350
1338-1350
17β-HYDROXYSTEROID DEHYDROGENASE FROM THE FUNGUS Cochliobolus lunatus: BIOSYNTHESIS IN Mycolicibacterium neoaurum ACTINOBACTERIAL CELLS AND FUNCTIONAL CHARACTERISTICS
Аннотация
17β-Hydroxysteroid dehydrogenase (17β-HSD) is an enzyme used in biotechnology for obtaining testosterone from phytosterol. Heterologous 17β-HSD from the fungus Cochliobolus lunatus catalyzes the NADPH-dependent reduction of the 17-oxo group of androstenedione/androstadienedione, formed in the cells of mycolicibacteria as a result of their inherent polyenzyme process of oxidation of the aliphatic side chain of phytosterol, with the formation of testosterone/Δ1-dehydrotestosterone, respectively. The object of the study was heterologous 17β-HSD from the fungus C. lunatus (17β-HSDCl) with a 6xHis tag (6×His-17β-HSDCl), synthesized in the cells of actinobacteria Mycolicibacterium neoaurum. Isolation and purification of the recombinant enzyme was carried out using affinity chromatography. The enzyme preparation 6×His-17β-HSDCl exhibited the highest activity towards androstenedione. The activity of 6×His-17β-HSDCl depended on NADPH and was manifested in the pH range from 6.0 to 9.0 with an optimum at pH 7.0. Analysis of kinetic characteristics showed that the properties of the heterologous 6×His-17β-HSDCl enzyme synthesized in M. neoaurum cells are comparable to those obtained for the 17β-HSD enzyme isolated from the fungus C. lunatus, as well as for the recombinant 17β-HSDCl enzymes synthesized in Escherichia coli and Mycolicibacterium smegmatis cells. The results expand our knowledge of microbial 17β-HSDs and indicate the potential for using recombinant M. neoaurum strains expressing a codon-optimized cDNA sequence encoding 17β-HSDCl from the fungus C. lunatus for producing testosterone from phytosterol.
Biochemistry. 2025;90(9):1351-1364
1351-1364
OBTAINING A MULTI-TARGET FUSION PROTEIN BASED ON THE ANTITUMOR CYTOKINE TRAIL-DRS-B
Аннотация
The cytokine TRAIL is distinguished by its remarkable ability to preferentially induce apoptosis in transformed but not normal cells. Clinical trials of the recombinant extracellular domain of TRAIL and other first-generation DR4 and DRS death receptor agonists have shown very limited antitumor activity in patients. To enhance the antitumor effect, in this work we developed a multitarget recombinant fusion protein SRH-DRS-B-p48 based on the DRS-selective variant of the cytokine TRAIL-DRS-B for simultaneously effect on tumor cells (DR5-B-mediated apoptosis) and the tumor microenvironment, in particular, to suppress angiogenesis. For this purpose, a recombinant SRH-DRS-B-p48 fusion protein with antagonistic synthetic peptides (SRH and p48) to the VEGFR2 and FGFR1 receptors was modeled and produced. Interaction analysis of molecular trajectories in molecular dynamics showed that the SRH and p48 peptides form non-specific temporary contacts with the DRS-B domain. Using enzyme-linked immunosorbent assay, we showed that SRH-DRS-B-p48 was similar to DRS-B in its affinity for the death receptor DRS, and showed high affinity for VEGFR2 and FGFR1 with a dissociation constant in the nanomolar range. SRH-DRS-B-p48 killed tumor cells of various origin more effectively than DRS-B, and effectively destroyed tumor-like structures in 3D cell models. In addition, the fusion protein inhibited FGF2-mediated stimulation of fibroblast proliferation. Thus, the SRH-DRS-B-p48 fusion can be considered as a promising agent for the therapy of solid tumors of various origin.
Biochemistry. 2025;90(9):1365-1376
1365-1376
PROGRAMMABLE DNA CLEAVAGE BY CYANOBACTERIAL ARGONAUTES
Аннотация
Argonautes are an evolutionarily conserved family of proteins that can recognize and cleave nucleic acids using complementary guide molecules. Eukaryotic Argonautes play a major role in RNA interference, using small RNAs to target mRNA. Prokaryotic Argonautes are much more diverse and predominantly recognize target DNA. Studying new Argonaute proteins, which are active under a wide range of conditions, is important for both understanding their functions and developing new genetic tools. The disadvantage of many previously studied Argonautes is their low activity at low and moderate temperatures. In this work, we isolated and characterized Argonautes from psychrotolerant cyanobacteria Cyanobacterium stanieri and Calothrix sp., CstAgo and CspAgo. Both proteins use short DNA guides to recognize DNA targets. CstAgo does not have strong preferences for the structure of the 5' end of guide DNA, while CspAgo demonstrates a weak preference for the 5'-terminal nucleotide. CstAgo has higher activity and is able to cleave single-stranded DNA at temperatures between 10 and 50 °C. CspAgo is more cold-sensitive but is capable of cleaving double-stranded plasmid DNA using specific guides. Therefore, the studied proteins could potentially be used for genetic manipulations of DNA.
Biochemistry. 2025;90(9):1377-1390
1377-1390
THE OVERALL EQUATION OF PHOTOSYNTHESIS AND THE SOURCE OF MOLECULAR OXYGEN: TUTORIAL ANALYSIS OF THE FORMAL PARADOX
Аннотация
In the article, we discuss the seeming paradox associated with molecular oxygen being evolved during photosynthesis. After van Niel's work in the early 1930s, it became clear that in oxygenic photosynthesis, molecular oxygen originates from the water oxygen atoms rather than those of carbon dioxide. At the same time, one can see from the overall equation of photosynthesis, n CO2 + n H2O — hν → (C H2O)n + n O2, that the amount of photosynthetically produced oxygen exceeds the amount that could be provided by the water molecules involved in the reactions. This paradox can be resolved by a detailed (although not going beyond the basic course of biochemistry) analysis of the light and dark reactions of photosynthesis leading to the incorporation of a carbon from dioxide molecule into a carbohydrate and the formation of molecular oxygen. However, despite this paradox can be solved simply enough, it is not widely discussed, and the solution does not seem quite evident. Among the reasons for this, the fact that the dark reactions of photosynthesis are commonly written schematically both in scientific and educational literature, without carefully specifying all the components included in the reactions, may play a role. We believe that the analysis of this paradox and the underlying physico-chemical principles of photosynthesis can be useful for students specializing in biochemistry as a spectacular educational and methodological example.
Biochemistry. 2025;90(9):1391-1400
1391-1400