Biochemistry (Moscow)最新文献

Abstract

The Keap1-Nrf2 pathway is an essential system that maintains redox homeostasis and modulates key metabolic processes, including metabolism of amino acids to promote the synthesis of antioxidant enzymes. Inhibitors of the protein-protein interaction (PPI) between Keap1 and Nrf2 have emerged as a promising strategy for developing novel classes of antioxidant agents that selectively activate this pathway without off-target effects. Carotenoids, a large family of lipophilic isoprenoids synthesized by all photosynthetic organisms, are well-known for their antioxidant activities. However, the ability of carotenoids to inhibit the Keap1-Nrf2 PPI through the involvement of specific amino acid residues has not yet been revealed. We utilized molecular docking, molecular dynamic simulations, and pharmacokinetic prediction techniques to investigate the potential of eight oxygenated carotenoids, known as xanthophylls, to inhibit Keap1. Among the compounds investigated, fucoxanthin and astaxanthin established multiple hydrogen-bonding and hydrophobic interactions within the Kelch domain of Keap1, showing remarkable binding affinities. Furthermore, fucoxanthin and astaxanthin displayed the ability to form a stable complex with Keap1 and fit into the binding pocket of its Kelch domain. These analyses led to the identification of critical amino acid residues in the binding pocket of Keap1 which are involved in the interaction with carotenoid xanthophylls. Our analyses further revealed that fucoxanthin and astaxanthin demonstrate a favorable safety profile and possess pharmacokinetic properties consistent with acceptable drug-like characteristics. These findings lay the preliminary foundation for developing a novel class of Keap1-Nrf2 PPI inhibitors with potential applications against oxidative stress-related diseases.

Current stage of proteomic research in the field of biology, medicine, development of new drugs, population screening, or personalized approaches to therapy dictates the need to analyze large sets of samples within the reasonable experimental time. Until recently, mass spectrometry measurements in proteomics were characterized as unique in identifying and quantifying cellular protein composition, but low throughput, requiring many hours to analyze a single sample. This was in conflict with the dynamics of changes in biological systems at the whole cellular proteome level upon the influence of external and internal factors. Thus, low speed of the whole proteome analysis has become the main factor limiting developments in functional proteomics, where it is necessary to annotate intracellular processes not only in a wide range of conditions, but also over a long period of time. Enormous level of heterogeneity of tissue cells or tumors, even of the same type, dictates the need to analyze biological systems at the level of individual cells. These studies involve obtaining molecular characteristics for tens, if not hundreds of thousands of individual cells, including their whole proteome profiles. Development of mass spectrometry technologies providing high resolution and mass measurement accuracy, predictive chromatography, new methods for peptide separation by ion mobility and processing of proteomic data based on artificial intelligence algorithms have opened a way for significant, if not radical, increase in the throughput of whole proteome analysis and led to implementation of the novel concept of ultrafast proteomics. Work done just in the last few years has demonstrated the proteome-wide analysis throughput of several hundred samples per day at a depth of several thousand proteins, levels unimaginable three or four years ago. The review examines background of these developments, as well as modern methods and approaches that implement ultrafast analysis of the entire proteome.

One of the most vital processes of the body is the cardiovascular system's proper operation. Physiological processes in the heart are regulated by the balance of cardioprotective and pathological mechanisms. The insulin-like growth factor system (IGF system, IGF signaling pathway) plays a pivotal role in regulating growth and development of various cells and tissues. In myocardium, the IGF system provides cardioprotective effects as well as participates in pathological processes. This review summarizes recent data on the role of IGF signaling in cardioprotection and pathogenesis of various cardiovascular diseases, as well as analyzes severity of these effects in various scenarios.

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome that develops in patients with severe liver dysfunction and/or portocaval shunting. Despite more than a century of research into the relationship between liver damage and development of encephalopathy, pathogenetic mechanisms of hepatic encephalopathy have not yet been fully elucidated. It is generally recognized, however, that the main trigger of neurologic complications in hepatic encephalopathy is the neurotoxin ammonia/ammonium, concentration of which in the blood increases to toxic levels (hyperammonemia), when detoxification function of the liver is impaired. Freely penetrating into brain cells and affecting NMDA-receptor-mediated signaling, ammonia triggers a pathological cascade leading to the sharp inhibition of aerobic glucose metabolism, oxidative stress, brain hypoperfusion, nerve cell damage, and formation of neurological deficits. Brain hypoperfusion, in turn, could be due to the impaired oxygen transport function of erythrocytes, because of the disturbed energy metabolism that occurs in the membranes and inside erythrocytes and controls affinity of hemoglobin for oxygen, which determines the degree of oxygenation of blood and tissues. In our recent study, this causal relationship was confirmed and novel ammonium-induced pro-oxidant effect mediated by excessive activation of NMDA receptors leading to impaired oxygen transport function of erythrocytes was revealed. For a more complete evaluation of "erythrocytic" factors that diminish brain oxygenation and lead to encephalopathy, in this study, activity of the enzymes and concentration of metabolites of glycolysis and Rapoport-Lubering shunt, as well as morphological characteristics of erythrocytes from the rats with acute hyperammoniemia were determined. To elucidate the role of NMDA receptors in the above processes, MK-801, a non-competitive receptor antagonist, was used. Based on the obtained results it can be concluded that it is necessary to consider ammonium-induced morphofunctional disorders of erythrocytes and hemoglobinemia which can occur as a result of alterations in highly integrated networks of metabolic pathways may act as an additional systemic "erythrocytic" pathogenetic factor to prevent the onset and progression of cerebral hypoperfusion in hepatic encephalopathy accompanied by hyperammonemia.

High-affinity and specific agents are widely applied in various areas, including diagnostics, scientific research, and disease therapy (as drugs and drug delivery systems). It takes significant time to develop them. For this reason, development of high-affinity agents extensively utilizes computer methods at various stages for the analysis and modeling of these molecules. The review describes the main affinity and specific agents, such as monoclonal antibodies and their fragments, antibody mimetics, aptamers, and molecularly imprinted polymers. The methods of their obtaining as well as their main advantages and disadvantages are briefly described, with special attention focused on the molecular modeling methods used for their analysis and development.

The lipoxygenase cascade in plants is a source of oxylipins (oxidized fatty acid derivatives), which play an important role in regulatory processes and formation of plant response to stress factors. Some of the most common enzymes of the lipoxygenase cascade are 13-specific hydroperoxide lyases (HPLs, also called hemiacetal synthases) of the CYP74B subfamily. In this work, we identified and cloned the CYP74B34 gene from carrot (Daucus carota L.) and described the biochemical properties of the corresponding recombinant enzyme. The CYP74B34 enzyme was active towards 9- and 13-hydroperoxides of linoleic (9-HPOD and 13-HPOD, respectively) and α-linolenic (9-HPOT and 13-HPOT, respectively) acids. CYP74B34 specifically converted 9-HPOT and 13-HPOT into aldo acids (HPL products). The transformation of 13-HPOD led to the formation of aldo acids and epoxyalcohols [products of epoxyalcohol synthase (EAS) activity] as major and minor products, respectively. At the same time, conversion of 9-HPOD resulted in the formation of epoxyalcohols as the main products and aldo acids as the minor ones. Therefore, CYP74B34 is the first enzyme with a double HPL/EAS activity described in carrot. The presence of these catalytic activities was confirmed by analysis of the oxylipin profiles for the roots from young seedlings and mature plants. In addition, we substituted amino acid residues in one of the catalytically essential sites of the CYP74B34 and CYP74B33 proteins and investigated the properties of the obtained mutant enzymes.

The phenomenon of paramutation describes the interaction between two alleles, in which one allele initiates inherited epigenetic conversion of another allele without affecting the DNA sequence. Epigenetic transformations due to paramutation are accompanied by the change in DNA and/or histone methylation patterns, affecting gene expression. Studies of paramutation in plants and animals have identified small non-coding RNAs as the main effector molecules required for the initiation of epigenetic changes in gene loci. Due to the fact that small non-coding RNAs can be transmitted across generations, the paramutation effect can be inherited and maintained in a population. In this review, we will systematically analyze examples of paramutation in different living systems described so far, highlighting common and different molecular and genetic aspects of paramutation between organisms, and considering the role of this phenomenon in evolution.

Optogenetics, the method of light-controlled regulation of cellular processes is based on the use of the channelrhodopsins that directly generate photoinduced currents. Most of the channelrhodopsin genes have been identified in the green microalgae Chlorophyta, and the demand for increasing the number of functionally characterized channelrhodopsins and the diversity of their photochemical parameters keeps growing. We performed the expression analysis of cation channelrhodopsin (CCR) genes in natural isolates of microalgae of the genera Haematococcus and Bracteacoccus from the unique Arctic Circle region. The identified full-length CCR transcript of H. lacustris is the product of alternative splicing and encodes the Hl98CCR2 protein with no photochemical activity. The 5'-partial fragment of the B. aggregatus CCR transcript encodes the Ba34CCR protein containing a conserved TM1-TM7 membrane domain and a short cytosolic fragment. Upon heterologous expression of the TM1-TM7 fragment in CHO-K1 cell culture, light-dependent current generation was observed with the parameters corresponding to those of the CCR. The first discovered functional channelrhodopsin of Bracteacoccus has no close CCR homologues and may be of interest as a candidate for optogenetics.