Lel A. Drachev and the Direct Electrometric Method
AbstractIn the bioenergetics studies, the direct electrometric method played an important role. This method is based on measuring the electrical potential difference (Δψ) between two compartments of the experimental cell generated by some membrane proteins. These proteins are incorporated into closed lipid –protein membrane vesicles associated with an artificial lipid membrane that separates the compartments. The very existence of such proteins able to generate Δψ was one of the consequences of Peter Mitchell ’s chemiosmotic concept. The discovery and investigation of their functioning contributed to the recognit...
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
A Novel Two-Domain Laccase with Middle Redox Potential: Physicochemical and Structural Properties
AbstractThe gene for a previously unexplored two-domain laccase was identified in the genome of actinobacteriumStreptomyces carpinensis VKM Ac-1300. The two-domain laccase, named ScaSL, was produced in a heterologous expression system (Escherichia coli strain M15 [pREP4]). The enzyme was purified to homogeneity using affinity chromatography. ScaSL laccase, like most two-domain laccases, exhibited activity in the homotrimer form. However, unlike the most two-domain laccases, it was also active in multimeric forms. The enzyme exhibited maximum activity at 80 °C and was thermally stable. Half-inactivation time of ScaSL at 80...
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
Proteomic Approach to Investigating Expression, Localization, and Functions of the SOWAHD Gene Protein Product during Granulocytic Differentiation
AbstractCataloging human proteins and evaluation of their expression, cellular localization, functions, and potential medical significance are important tasks for the global proteomic community. At present, localization and functions of protein products for almost half of protein-coding genes remain unknown or poorly understood. Investigation of organelle proteomes is a promising approach to uncovering localization and functions of human proteins. Nuclear proteome is of particular interest because many nuclear proteins, e.g., transcription factors, regulate functions that determine cell fate. Meta-analysis of the nuclear p...
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
Femtosecond Dynamics of Excited States of Chlorophyll Tetramer in Water-Soluble Chlorophyll-Binding Protein BoWSCP
AbstractThe paper reports on the absorption dynamics of chlorophyll a in a symmetric tetrameric complex of the water-soluble chlorophyll-binding protein BoWSCP. It was measured by a broadband femtosecond laser pump-probe spectroscopy within the range from 400 to 750 nm and with a time resolution of 20 fs-200 ps. When BoWSCP was excited in the region of the Soret band at a wavelength of 430 nm, nonradiative intramolecular conversion S3→S1 was observed with a characteristic time of 83 ± 9 fs. When the complex was excited in the region of the Qy band at 670 nm, relaxation transition between two excitonic state...
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
Catalytic and Electrocatalytic Mechanisms of Cytochromes P450 in the Development of Biosensors and Bioreactors
AbstractCytochromes P450 are a unique family of enzymes found in all Kingdoms of living organisms (animals, bacteria, plants, fungi, and archaea), whose main function is biotransformation of exogenous and endogenous compounds. The review discusses approaches to enhancing the efficiency of electrocatalysis by cytochromes P450 for their use in biotechnology and design of biosensors and describes main methods in the development of reconstituted and electrochemical catalytic systems based on the biochemical mechanism of cytochromes P450, as well as and modern trends for their practical application. (Source: Biochemistry (Moscow))
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
Similarities and Differences in Photochemistry of Type I and Type II Rhodopsins
AbstractThe diversity of the retinal-containing proteins (rhodopsins) in nature is extremely large. Fundamental similarity of the structure and photochemical properties unites them into one family. However, there is still a debate about the origin of retinal-containing proteins: divergent or convergent evolution? In this review, based on the results of our own and literature data, a comparative analysis of the similarities and differences in the photoconversion of the rhodopsin of types I and II is carried out. The results of experimental studies of the forward and reverse photoreactions of the bacteriorhodopsin (type ...
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
Retinal-Based Anion Pump from the Cyanobacterium Tolypothrix campylonemoides
AbstractIn this work, TcaR rhodopsin from the cyanobacteriumTolypothrix campylonemoides was characterized. Analysis of the amino acid sequence of TcaR revealed that this protein possesses a TSD motif that differs by only one amino acid from the TSA motif of the known halorhodopsin chloride pump. The TcaR protein was expressed inE. coli, purified, and incorporated into proteoliposomes and nanodiscs. Functional activity was measured by electric current generation through the planar bilayer lipid membranes (BLMs) with proteoliposomes adsorbed on one side of the membrane surface, as well as by fluorescence using the voltage-...
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
Biomarkers of the End-Stage Renal Disease Progression: Beyond the GFR
AbstractChronic kidney disease can progress to the end-stage renal disease (ESRD) characterized by a high risk of morbidity and mortality. ESRD requires immediate therapy or even dialysis or kidney transplantation, therefore, its timely diagnostics is critical for many patients. ESRD is associated with pathological changes, such as inflammation, fibrosis, endocrine disorders, and epigenetic changes in various cells, which could serve as ESRD markers. The review summarizes information on conventional and new ESRD biomarkers that can be assessed in kidney tissue, blood, and urine. Some biomarkers are specific to a particular...
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
Electrical Signals at the Plasma Membrane and Their Influence on Chlorophyll Fluorescence of Chara Chloroplasts in vivo
AbstractAction potentials of plant cells are engaged in the regulation of many cell processes, including photosynthesis and cytoplasmic streaming. Excitable cells of characean algae submerged in a medium with an elevated K+ content are capable of generating hyperpolarizing electrical responses. These active responses of plasma membrane originate upon the passage of inward electric current comparable in strength to natural currents circulating in illuminatedChara internodes. So far, it remained unknown whether the hyperpolarizing electrical signals inChara affect the photosynthetic activity. Here, we showed that the negativ...
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
Investigation of the Mechanism of Membrane Potential Generation by Heme-Copper Respiratory Oxidases in a Real Time Mode
AbstractHeme-copper respiratory oxidases are highly efficient molecular machines. These membrane enzymes catalyze the final step of cellular respiration in eukaryotes and many prokaryotes: the transfer of electrons from cytochromes or quinols to molecular oxygen and oxygen reduction to water. The free energy released in this redox reaction is converted by heme-copper respiratory oxidases into the transmembrane gradient of the electrochemical potential of hydrogen ions ΔμH+). Heme-copper respiratory oxidases have a unique mechanism for generating ΔμH+, namely, a redox-coupled proton pump. A combination of direct electro...
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
Channelrhodopsins: From Phototaxis to Optogenetics
AbstractChannelrhodopsins stand out among other retinal proteins because of their capacity to generate passive ionic currents following photoactivation. Owing to that, channelrhodopsins are widely used in neuroscience and cardiology as instruments for optogenetic manipulation of the activity of excitable cells. Photocurrents generated by channelrhodopsins were first discovered in the cells of green algae in the 1970s. In this review we describe this discovery and discuss the current state of research in the field. (Source: Biochemistry (Moscow))
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
Role and Molecular Mechanisms of Alternative Splicing of Th2-Cytokines IL-4 and IL-5 in Atopic Bronchial Asthma
AbstractBronchial asthma (BA) is a heterogeneous chronic inflammatory disease of the respiratory tract. Allergic (atopic) asthma is the most common (up to 80% of cases) phenotype developing through the Th2-dependent mechanisms involving cytokines: IL-4, IL-5, IL-9, and IL-13. The genes encoding Th2-cytokines have a mosaic structure (encode exons and introns). Therefore, several mature mRNA transcripts and protein isoforms can be derived from a single mRNA precursor through alternative splicing, and they may contribute to BA pathogenesis. Analysis of the published studies and databases revealed existence of the alternative ...
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
Ion Channels in Electrical Signaling in Higher Plants
AbstractElectrical signals (ESs) appearing in plants under the action of various external factors play an important role in adaptation to changing environmental conditions. Generation of ES in higher plant cells is associated with activation of Ca2+, K+, and anion fluxes, as well as with changes in the activity of plasma membrane H+-ATPase. In the present review, molecular nature of the ion channels contributing to ESs transmission in higher plants is analyzed based on comparison of the data from molecular-genetic and electrophysiological studies. Based on such characteristics of ion channels as selectivity, activation mec...
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
Electron Transport in Chloroplasts: Regulation and Alternative Pathways of Electron Transfer
AbstractThis work represents an overview of electron transport regulation in chloroplasts as considered in the context of structure-function organization of photosynthetic apparatus in plants. Main focus of the article is on bifurcated oxidation of plastoquinol by the cytochrome b6f complex, which represents the rate-limiting step of electron transfer between photosystems II and I. Electron transport along the chains of non-cyclic, cyclic, and pseudocyclic electron flow, their relationships to generation of the trans-thylakoid difference in electrochemical potentials of protons in chloroplasts, and pH-dependent mechan...
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
Generation of Membrane Potential by Cytochrome bd
AbstractAn overview of current notions on the mechanism of generation of a transmembrane electric potential difference (Δψ) during the catalytic cycle of abd-type triheme terminal quinol oxidase is presented in this work. It is suggested that the main contribution to Δψ formation is made by the movement of H+ across the membrane along the intra-protein hydrophilic proton-conducting pathway from the cytoplasm to the active site for oxygen reduction of this bacterial enzyme. (Source: Biochemistry (Moscow))
Source: Biochemistry (Moscow) - October 1, 2023 Category: Biochemistry Source Type: research
