Human 14-3-3 Proteins Site-selectively Bind the Mutational Hotspot Region of SARS-CoV-2 Nucleoprotein Modulating its Phosphoregulation.

Phosphorylation of SARS-CoV-2 nucleoprotein recruits human cytosolic 14-3-3 proteins playing a well-recognized role in replication of many viruses. Here we use genetic code expansion to demonstrate that 14-3-3 binding is triggered by phosphorylation of SARS-CoV-2 nucleoprotein at either of two pseudo-repeats centered at Ser197 and Thr205. According to fluorescence anisotropy measurements, the pT205-motif,presentin SARS-CoV-2 but not in SARS-CoV, is preferred over the pS197-motif by all seven human 14-3-3 isoforms, which collectively display an unforeseen pT205/pS197 peptide binding selectivity hierarchy.

Silkworm carotenoprotein as an efficient carotenoid extractor, solubilizer and transporter.

Found in many organisms, water-soluble carotenoproteins are prospective antioxidant nanocarriers for biomedical applications. Yet, the toolkit of characterized carotenoproteins is rather limited: such proteins are either too specific binders of only few different carotenoids, or their ability to transfer carotenoids to various acceptor systems is unknown. Here, by focusing on a recently characterized recombinant ~27-kDa Carotenoid-Binding Protein from Bombyx mori (BmCBP) [Slonimskiy et al.

Electrophoresis-Assisted Multilayer Assembly of Nanoparticles for Sensitive Lateral Flow Immunoassay.

Lateral flow immunoassay (LFIA) is a rapid, simple, and inexpensive point-of-need method. A major limitation of LFIA is a high limit of detection (LOD), which impacts its diagnostic sensitivity. To overcome this limitation, we introduce a signal-enhancement procedure that is performed after completing LFIA and involves controllably moving biotin- and streptavidin-functionalized gold nanoparticles by electrophoresis.

Structural basis for the carotenoid binding and transport function of a START domain.

STARD3, a steroidogenic acute regulatory lipid transfer protein, was identified as a key xanthophyll-binding protein in the human retina. STARD3 and its homologs in invertebrates are known to bind and transport carotenoids, but this lacks structural elucidation. Here, we report high-resolution crystal structures of the apo- and zeaxanthin (ZEA)-bound carotenoid-binding protein from silkworm Bombyx mori (BmCBP).

Development of Lateral Flow Test-System for the Immunoassay of Dibutyl Phthalate in Natural Waters.

The use of a large amount of toxic synthetic materials leads to an increase in the pollution of environmental objects. Phthalates are compounds structurally related to esters of phthalic acid that are widely used in the manufacturing of synthetic packaging materials as plasticizers. Their danger is conditioned by leaching into the environment and penetrating into living organisms with negative consequences and effects on various organs and tissues.

Multifarious analytical capabilities of the UV/Vis protein fluorescence in blood plasma.

Autofluorescence of blood plasma has been broadly considered as a prospective disease screening method. However, the assessment of such intrinsic fluorescence is mostly phenomenological, and its origin is still not fully understood, complicating its use in the clinical practice. Here we present the detailed evaluation of analytical capabilities, variability, and formation of blood plasma protein fluorescence based on the open dataset of excitation-emission matrices measured for ∼300 patients with suspected colorectal cancer, and our supporting model experiments.

Confocal Raman Micro-Spectroscopy for Discrimination of Glycerol Diffusivity in Ex Vivo Porcine .

(DM) is a connective tissue with dense collagen, which is a protective membrane surrounding the human brain. The optical clearing (OC) method was used to make DM more transparent, thereby allowing to increase in-depth investigation by confocal Raman micro-spectroscopy and estimate the diffusivity of 50% glycerol and water migration. Glycerol concentration was obtained, and the diffusion coefficient was calculated, which ranged from 9.

Betaine-Based Deep Eutectic Solvent as a New Media for Laccase-Catalyzed Template-Guided Polymerization/Copolymerization of Aniline and 3-Aminobenzoic Acid.

Deep eutectic solvents (DESs) can compensate for some of the major drawbacks of traditional organic solvents and ionic liquids and meet all requirements of green chemistry. However, the potential of their use as a medium for biocatalytic reactions has not been adequately studied. In this work we used the DES betaine-glycerol with a molar ratio of 1:2 as co-solvent for enzymatic template-guided polymerization/copolymerization of aniline (ANI) and 3-aminobenzoic acid (3ABA).

A primordial Orange Carotenoid Protein: Structure, photoswitching activity and evolutionary aspects.

Cyanobacteria are photosynthesizing prokaryotes responsible for the Great Oxygenation Event on Earth ~2.5 Ga years ago. They use a specific photoprotective mechanism based on the 35-kDa photoactive Orange Carotenoid Protein (OCP), a promising target for developing novel optogenetic tools and for biomass engineering.

Expression of Recombinant CTLA-4 and PD-L1 Proteins Fused with Thioredoxin, and Determination of Their Ligand-Binding Activities.

Background: The use of chimeric proteins that selectively interact with various immune cell receptors to treat oncology patients has increased. One effective way to obtain recombinant proteins is to use the expression system. However, in eukaryotic protein production in , several difficulties arise that can be solved by fusing the target protein with thioredoxin.

The First Yeast Models Expressing Hepatitis B Virus X Protein: Changes in Mitochondrial Morphology and Functions.

Chronic hepatitis B virus infection is the dominant cause of hepatocellular carcinoma, the main cause of cancer death. HBx protein, a multifunctional protein, is essential for pathogenesis development; however, the underlying mechanisms are not fully understood. The complexity of the system itself, and the intricate interplay of many factors make it difficult to advance in understanding the mechanisms underlying these processes.

The Effect of Different Substrates on the Morphological Features and Polyols Production of Yeast during Long-Lasting Cultivation.

The study on the influence of different glucose concentrations (2%, 0.5%, and 0.2%) and glycerol (1%) on the morphological and physiological features, as well as the composition of soluble carbohydrates, was performed using yeast.

Comparative Analysis of and Exoproteomes Demonstrates "Shades of Gray" in the Concept of White-Rotting Fungi.

White-rot basidiomycete fungi are a unique group of organisms that evolved an unprecedented arsenal of extracellular enzymes for an efficient degradation of all components of wood such as cellulose, hemicelluloses and lignin. The exoproteomes of white-rot fungi represent a natural enzymatic toolbox for white biotechnology. Currently, only exoproteomes of a narrow taxonomic group of white-rot fungi-fungi belonging to the Polyporales order-are extensively studied.

"Fundamental principles of photodynamic, laser and PUVA therapy": a session of the Russian Photobiology Society 9th Congress (Shepsi, Krasnodar region, Russia; September, 12-19, 2021).

At the section "Fundamentals of photodynamic, laser and PUVA therapy," 32 reports were presented in full-time and on-line format. Representatives of various scientific schools reported on the results of fundamental and applied research on the processes occurring at the cellular and organismal levels upon irradiation with low-intensity red light and upon the introduction of photosensitizers of various nature, followed by laser irradiation. Scientific reports proposed new photosensitizers, as well as their conjugates with biologically active molecules for fluorescent diagnostics and photodynamic therapy of oncological diseases.

Characterization of optical clearing mechanisms in muscle during treatment with glycerol and gadobutrol solutions.

The recent increasing interest in the application of radiology contrasting agents to create transparency in biological tissues implies that the diffusion properties of those agents need evaluation. The comparison of those properties with the ones obtained for other optical clearing agents allows to perform an optimized agent selection to create optimized transparency in clinical applications. In this study, the evaluation and comparison of the diffusion properties of gadobutrol and glycerol in skeletal muscle was made, showing that although gadobutrol has a higher molar mass than glycerol, its low viscosity allows for a faster diffusion in the muscle.

Anti-Stokes fluorescence excitation reveals conformational mobility of the C-phycocyanin chromophores.

The structural organization of natural pigment-protein complexes provides a specific environment for the chromophore groups. Yet, proteins are inherently dynamic and conformationally mobile. In this work, we demonstrate the heterogeneity of chromophores of C-phycocyanin (C-PC) from .

The role of the local environment on the structural heterogeneity of carotenoid β-ionone rings.

Our analysis of the X-ray crystal structure of canthaxanthin (CAN) showed that its ketolated β-ionone rings can adopt two energetically equal, but structurally distinct puckers. Quantum chemistry calculations revealed that the potential energy surface of the β-ionone ring rotation over the plane of the conjugated π-system in carotenoids depends on the pucker state of the β-ring. Considering different pucker states and β-ionone ring rotation, we found six separate local minima on the potential energy surface defining the geometry of the keto-β-ionone ring-two cis and one trans orientation for each of two pucker states.

Optical clearing and testing of lung tissue using inhalation aerosols: prospects for monitoring the action of viral infections.

Optical clearing of the lung tissue aims to make it more transparent to light by minimizing light scattering, thus allowing reconstruction of the three-dimensional structure of the tissue with a much better resolution. This is of great importance for monitoring of viral infection impact on the alveolar structure of the tissue and oxygen transport. Optical clearing agents (OCAs) can provide not only lesser light scattering of tissue components but also may influence the molecular transport function of the alveolar membrane.

Structural basis for the recognition by 14-3-3 proteins of a conditional binding site within the oligomerization domain of human nucleophosmin.

Nucleophosmin 1 (NPM1) is a multifunctional protein regulating ribosome biogenesis, centrosome duplication and chromatin remodeling. Being a major nucleolar protein, NPM1 can migrate to the nucleus and the cytoplasm, which is controlled by changes of NPM1 oligomerization and interaction with other cell factors. NPM1 forms a stable pentamer with its N-terminal structured domain, where two nuclear export signals and several phosphorylation sites reside.

Shotgun proteomic profiling of dormant, 'non-culturable' Mycobacterium tuberculosis.

Dormant cells of Mycobacterium tuberculosis, in addition to low metabolic activity and a high level of drug resistance, are characterized by 'non-culturability'-a specific reversible state of the inability of the cells to grow on solid media. The biochemical characterization of this physiological state of the pathogen is only superficial, pending clarification of the metabolic processes that may exist in such cells. In this study, applying LC-MS proteomic profiling, we report the analysis of proteins accumulated in dormant, 'non-culturable' M.

Application of Genetically Encoded Photoconvertible Protein SAASoti for the Study of Enzyme Activity in a Single Live Cell by Fluorescence Correlation Microscopy.

Fluorescent Correlation Spectroscopy (FCS) allows us to determine interactions of labeled proteins or changes in the oligomeric state. The FCS method needs a low amount of fluorescent dye, near nanomolar concentrations. To control the amount of fluorescent dye, we used new photoconvertible FP SAASoti.

Silent Antibodies Start Talking: Enhanced Lateral Flow Serodiagnosis with Two-Stage Incorporation of Labels into Immune Complexes.

The presence of pathogen-specific antibodies in the blood is widely controlled by a serodiagnostic technique based on the lateral flow immunoassay (LFIA). However, its common one-stage format with an antigen immobilized in the binding zone of a test strip and a nanodispersed label conjugated with immunoglobulin-binding proteins is associated with risks of very low analytical signals. In this study, the first stage of the immunochromatographic serodiagnosis was carried out in its traditional format using a conjugate of gold nanoparticles with staphylococcal immunoglobulin-binding protein A and an antigen immobilized on a working membrane.

Reconstitution of the functional Carotenoid-Binding Protein from silkworm in E. coli.

Natural water-soluble carotenoproteins are promising antioxidant nanocarriers for biomedical applications. The Carotenoid-Binding Protein from silkworm Bombyx mori (BmCBP) is responsible for depositing carotenoids in cocoons. This determines the silk coloration, which is relevant for sericulture for four thousand years.