Vol 50, No 4 (2024)

I have talked about Yuri Anatolyevich in many popular articles. We have more than 30 publications in common. In particular, more than 10 are on RNA polymerase:, 5 are on ATPase, 1 (out of 3) is devoted to photoaffinity modification of the active centers of RNA polymerase; 18 articles and patents on interferons, 10 of which involve Yuri Anatolyevich: 6 of the most significant, 7 articles and patents (3 of which involve Yuri Anatolyevich) are devoted to the problem of a vaccine against the Hepatitis A virus.

I was part of the team that received the USSR State Prize in 1981 for work on RNA polymerase, headed by Yuri Anatolyevich. It should also be noted that with the active assistance of Yu. A. Ovchinnikov, industrial production of interferon was organized, which I called Reaferon (recombinant alpha interferon), and I, together with other participants in this difficult work, was awarded the Lenin Prize. Reaferon is sold in pharmacies to this day and will be used for a very long time. I have provided this data so that it is clear how close our cooperation was.

Ubiquitination, one of the most common posttranslational modifications of proteins, has a significant impact on its functions, such as stability, activity and cellular localization. Disorders in the processes of ubiquitination and deubiquitination are associated with various oncological and neurodegenerative diseases. The complexity of ubiquitin signaling – monoubiquitination and polyubiquitination with different lengths and types of interconnections between ubiquitins – determines their versatility and ability to regulate hundreds of different cellular processes. Advanced biochemical, mass spectrometric and computational methods are required for in-depth understanding of the mechanisms of assembly and disassembly, detection of ubiquitin chains and their signal transmission. Recent scientific achievements make it possible to identify the ubiquitination of proteins and the structure of ubiquitin chains, however, there are still a considerable number of unresolved issues in this area. Current review claims for a detailed analysis of the current understanding of the architectonics of the ubiquitin chains.

Many studies confirm that substances of natural origin have a pronounced affinity for type 2 diabetes mellitus (T2DM) therapeutic targets. At the moment, there is growing interest in bioactive peptides, phytochemicals, and drugs from other natural sources as highly effective, safe and promising antidiabetic agents. Natural sources are a promising resource for regulating several pathological pathways in T2DM. The review describes ways to mitigate insulin resistance and tissue sensitivity to glucose through PTP1β (protein tyrosine phosphatase 1β), GLP-1R (glucagon-like peptide receptor), DPP-4 (dipeptidyl peptidase-4), AMPK (adenosine monophosphate activated protein kinase), MAPK (mitogen-activated protein kinase). Regulation of obesity and oxidative stress development through CCN3 (nephroblastoma overexpressed gene), PPAR-γ (peroxisome proliferator-activated receptor γ), Nrf2 (nuclear factor erythroid-related factor 2), FFAR (free fatty acid receptors), 11β-HSD1 (11β-hydroxysteroid dehydrogenase). Regulation of hyperglycemia through alpha-amylase inhibitors, regulation of glucose metabolism through GFAT (glutamine fructose-6-phosphate aminotransferase), FOXO1 (forkhead box protein O1), GLUT4 (glucose transporter type 4), PGC-1α (receptor gamma coactivator 1α activating peroxisome proliferator). The review examines the use of natural sources, from which low-molecular-weight and peptide compounds are used as T2DM targets modulators.

Optical microscopy has undergone significant changes in recent decades due to the breaking of the diffraction limit of optical resolution and the development of high-resolution imaging techniques, which are collectively known as fluorescence nanoscopy. These techniques allow researchers to observe biological structures and processes at a nanoscale level of detail, revealing previously hidden features and aiding in answering fundamental biological questions. Among the advanced methods of fluorescent nanoscopy are: STED (Stimulated Emission Depletion Microscopy), STORM (STochastic Optical Reconstruction Microscopy), PALM (Photo-activated Localization Microscopy), TIRF (Total Internal Reflection Fluorescence), SIM (Structured Illumination Microscopy), MINFLUX (Minimal Photon Fluxes), PAINT (Points Accumulation for Imaging in Nanoscale Topography) и RESOLFT (REversible Saturable Optical Fluorescence Transitions) and others. In addition, most of these methods make it possible to obtain volumetric (3D) images of the objects under study. In this review, we will look at the principles of these methods, their advantages and disadvantages, and their application in biological researches.

Scorpion α-neurotoxins are classical ligands of voltage-gated sodium channels that inhibit their inactivation. The strength of this effect depends on the organism and channel isoform, and the precise mechanisms explaining the differences in activity are still unknown. Previously, we have shown that scorpion α-toxins are characterized by a modular structure. They consist of a conserved and structurally stable core module and a variable and mobile specificity module, which determines the selectivity for different channels. We noted a higher mobility of the specificity module in toxins active against mammals compared to insect-active toxins. We then hypothesized that the enhanced mobility in mammal toxins was provided by two conserved glycine residues that enclose the N-terminal loop of the specificity module. To test this assumption, we obtained a derivative of the neurotoxin BeM9 from the venom of the scorpion Mesobuthus eupeus with two replacements of amino acid residues in the corresponding positions with glycine (A4G and Y17G). Unexpectedly, it turned out that BeM9^GG lost its activity against Na_v1.5 channel isoform, characteristic of mammalian cardiac muscle. A comparison of two known structures of voltage-gated sodium channel complexes with scorpion toxins made it possible to explain the observed effect. We hypothesize an essential role of the membrane in the interaction of toxins with the Na_v1.5 isoform.

Most of the modern cancer therapies are non-specific and have adverse side effects on the body. Nowadays, targeted cancer therapies are being developed, in particular using targeting peptides that selectively bind to cancer cells. The aim of the present work is to explore the prospects of using a peptide pHLIP that binds to cancer cells at decreased pH values, as a part of recombinant protein-peptide construct for cancer diagnosis and targeted therapy. Hybrid structures based on the fluorescent protein EGFP and a linker sequence connecting fluorescent protein to two different pHLIP variants were obtained. The effect of different linkers on the pH-dependent binding of the constructs to cells, as well as on the efficiency of EGFP chromophore synthesis within the hybrid construct was investigated.

A number of histidine-containing synthetic antifungal peptides with a “linear” type of amphipathicity (SAMP LTA) (F2Hx, H10F2, H10, where x = 7, 10, 13 and 16) have been synthesized and studied. Biological screening of such histidine-containing peptides for their antifungal and hemolytic activity was carried out. It has been shown that the presented histidine-containing SAMP LTAs are capable of effectively inhibiting the growth of opportunistic fungi Candida albicans and have low hemolytic activity in most cases not exceeding 10% even at their relatively high concentration of 400 μM in a medium containing erythrocytes. The antifungal activity of the studied peptides increases with increasing histidine residues in their composition, reaching the maximum value for the histidine-containing peptide F2H16 (MIC₅₀ = 1.0 µM). It has been shown that as the chain length of peptides increases, their hemolytic toxicity also increases. In terms of therapeutic significance, the optimal peptides in the presented series of peptides were F2H10 and F2H13, which have higher selectivity than the short or longer peptides F2H7 or F2H16. The therapeutic index (TI) for these peptides was 233, 247, 79 and 60, respectively. It has been shown that histidine-containing derivatives of peptides with phenylalanine residues at the N-terminus of the peptide (F2H10) are less effective compared to similar peptides (H10F2) containing phenylalanine residues at the C-terminus. Among all the studied peptides, the most active was the H10 peptide (MIC₅₀ = 0.7 µM), which does not contain phenylalanine residues, which in its antifungal activity is not only more effective than all other histidine-containing peptides, including the F2H16 peptide with 16 histidine residues, but also 4-5 times more effective than the antifungal peptide P113 (MIC₅₀ = 3.4 µM), a short active fragment of natural histatin 5, well known in the literature. Due to its relatively low hemolytic and high antifungal activity, the presented histidine-containing SAMP LTAs have relatively high TI values, more than 60. Among all the studied peptides, peptides H10 and P113 have minimal, almost zero, hemolytic activity. However, due to its higher antifungal activity, the selectivity of peptide H10 (TI > 1400) exceeds that of peptide P113 (TI > 340) by more than 4 times. Thus, peptide H10, due to its high antifungal activity, low hemolytic toxicity and, accordingly, high therapeutic significance, can be used as a promising antifungal peptide drug.

Two pairs of Cy-5-labeled dU and dC triphosphates with similar electroneutral fluorophore structures differing in the length of the hydrocarbon linker between the fluorophore and the nitrogenous base were synthesized. A comparative analysis of their substrate behavior in the rolling circle amplification (RCA) using Bst 3.0 DNA polymerase was carried out. It was found that nucleotides with a long linker between the fluorophore and pyrimidine base are more efficiently incorporated into the growing DNA chain, while nucleotides with a short linker inhibit RCA less. In each of the dU and dC pairs with similar fluorophores and linkers, fluorescently labeled uridine derivatives demonstrated a high embedding density. It was found that with simultaneous incorporation of labeled dU and dC, the inhibitory effect does not summarise. This gives grounds for a more careful study of various Cy5-dC variants in order to increase a sensitivity of the analysis with simultaneous introduction of labeled dU and dC.