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BioRxiv : the Preprint Server For... Jun 2024How can a single protein domain encode a conformational landscape with multiple stably-folded states, and how do those states interconvert? Here, we use real-time and...
How can a single protein domain encode a conformational landscape with multiple stably-folded states, and how do those states interconvert? Here, we use real-time and relaxation-dispersion NMR to characterize the conformational landscape of the circadian rhythm protein KaiB from . Unique among known natural metamorphic proteins, this KaiB variant spontaneously interconverts between two monomeric states: the "Ground" and "Fold-switched" (FS) state. KaiB in its FS state interacts with multiple binding partners, including the central KaiC protein, to regulate circadian rhythms. We find that KaiB itself takes hours to interconvert between the Ground and FS state, underscoring the ability of a single sequence to encode the slow process needed for function. We reveal the rate-limiting step between the Ground and FS state is the isomerization of three prolines in the fold-switching region by demonstrating interconversion acceleration by the prolyl isomerase CypA. The interconversion proceeds through a "partially disordered" (PD) state, where the C-terminal half becomes disordered while the N-terminal half remains stably folded. We discovered two additional properties of KaiB's landscape. Firstly, the Ground state experiences cold denaturation: at 4°C, the PD state becomes the majorly populated state. Secondly, the Ground state exchanges with a fourth state, the "Enigma" state, on the millisecond timescale. We combine AlphaFold2-based predictions and NMR chemical shift predictions to predict this "Enigma" state is a beta-strand register shift that eases buried charged residues, and support this structure experimentally. These results provide mechanistic insight in how evolution can design a single sequence that achieves specific timing needed for its function.
PubMed: 38895306
DOI: 10.1101/2024.06.03.597139 -
International Journal of Molecular... May 2024Dermatology and cosmetology currently prioritize healthy, youthful-looking skin. As a result, research is being conducted worldwide to uncover natural substances and...
Dermatology and cosmetology currently prioritize healthy, youthful-looking skin. As a result, research is being conducted worldwide to uncover natural substances and carriers that allow for controlled release, which could aid in the battle against a variety of skin illnesses and slow the aging process. This study examined the biological and physicochemical features of novel hydrogels containing cannabidiol (CBD) and α-terpineol (TER). The hydrogels were obtained from ε-caprolactone (CL) and poly(ethylene glycol) (PEG) copolymers, diethylene glycol (DEG), poly(tetrahydrofuran) (PTHF), 1,6-diisocyanatohexane (HDI), and chitosan (CHT) components, whereas the biodegradable oligomers were synthesized using the enzyme ring-opening polymerization (e-ROP) method. The in vitro release rate of the active compounds from the hydrogels was characterized by mainly first-order kinetics, without a "burst release". The antimicrobial, anti-inflammatory, cytotoxic, antioxidant, and anti-aging qualities of the designed drug delivery systems (DDSs) were evaluated. The findings indicate that the hydrogel carriers that were developed have the ability to scavenge free radicals and impact the activity of antioxidant enzymes while avoiding any negative effects on keratinocytes and fibroblasts. Furthermore, they have anti-inflammatory qualities by impeding protein denaturation as well as the activity of proteinase and lipoxygenase. Additionally, their ability to reduce the multiplication of pathogenic bacteria and inhibit the activity of collagenase and elastase has been demonstrated. Thus, the developed hydrogel carriers may be effective systems for the controlled delivery of CBD, which may become a valuable tool for cosmetologists and dermatologists.
Topics: Hydrogels; Cannabidiol; Skin; Humans; Cyclohexane Monoterpenes; Antioxidants; Regeneration; Polymers; Biocompatible Materials; Keratinocytes; HaCaT Cells; Drug Carriers; Drug Delivery Systems; Anti-Infective Agents
PubMed: 38892121
DOI: 10.3390/ijms25115934 -
Foods (Basel, Switzerland) Jun 2024Soy remains the legume protein of excellence for plant-based meat alternatives due to its fiber-forming potential. In this study, protein-rich powders from soy protein...
Soy remains the legume protein of excellence for plant-based meat alternatives due to its fiber-forming potential. In this study, protein-rich powders from soy protein isolate (SPI), concentrate (SPC), and their mixture (SPM) were thoroughly characterized for their proximate composition, nutritional quality, and physicochemical properties to understand their structuring behavior during high-moisture extrusion. SPI presented higher degrees of protein denaturation and aggregation, least gelation concentration and lower essential amino acid contents. Thus, an SPI:SPC combination (1:9 ratio, 70% protein) was extruded at three different screw speeds (300, 350, and 400 rpm) and two temperature profiles (120 and 140 °C maximum temperature). The effects of the processing parameters on the extrudates were evaluated for their appearance (fibrousness), texture (TPA, cutting force, and anisotropy), color, protein structure (FTIR), and trypsin inhibitors. Higher temperatures resulted in softer and darker extrudates, with increased visual and instrumental anisotropy. Increasing screw speeds led to softer and lighter extrudates, without a clear fibrousness effect. β-sheet structures decreased and intermolecular aggregates (A1) increased after extrusion, especially at 140 °C, together with the formation of intramolecular aggregates (A2). Extrusion also significantly decreased the amount of trypsin inhibitors (>90%). This study demonstrates that extrusion parameters need to be carefully selected to achieve meat analogs with optimal textural and nutritional characteristics.
PubMed: 38890977
DOI: 10.3390/foods13111748 -
Frontiers in Nutrition 2024Composite natural emulsifiers such as whey protein isolate (WPI) and chitosan (CS) are commonly used in Pickering emulsions to address the effect of thermal deformation...
Composite natural emulsifiers such as whey protein isolate (WPI) and chitosan (CS) are commonly used in Pickering emulsions to address the effect of thermal deformation of proteins before complexation with CS and heating after complexation. In this study, the properties of WPI and CS composites were investigated by complexing CS with either unmodified WPI or thermally denatured WPI (DWPI). Three types of composite particles were prepared, WPI-CS, DWPI-CS, and D(WPI-CS). Atomic force microscopy revealed that the composite particles formed larger aggregates with increased contour size and surface roughness compared to CS and WPI, whereas the interfacial tension decreased, indicating improved emulsifying abilities. Fourier-transform infrared analysis revealed differences in the hydrogen bonds between CS and WPI/DWPI. All three composite particles formed stable emulsions with droplet sizes of 20.00 ± 0.15, 27.80 ± 0.35, and 16.77 ± 0.51 μm, respectively. Thermal stability experiments revealed that the curcumin emulsion stabilized with WPI-CS and DWPI-CS exhibited relatively better thermal stability than that stabilized with D(WPI-CS). experiments results indicated that the bioaccessibility of the curcumin emulsion stabilized with WPI-CS was 61.18 ± 0.16%, significantly higher than that of the emulsions prepared with the other two composite particles ( < 0.05). This study will enable the customized design of WPI composite-based Pickering emulsions for application in the food and nutrition industries.
PubMed: 38887503
DOI: 10.3389/fnut.2024.1418120 -
Journal of Pharmacy & Bioallied Sciences Apr 2024contains andrograpanin, which is both anti-inflammatory and anti-infective. comprises over 150-200 species from the family . exerts various properties, including...
contains andrograpanin, which is both anti-inflammatory and anti-infective. comprises over 150-200 species from the family . exerts various properties, including anti-inflammatory property. Herbal mouthwash was made using and extract. The anti-inflammatory effect was evaluated using an albumin denaturation assay and egg albumin denaturation. The percentage of protein denaturation that is inhibited by the formulation of and indicates that it has strong anti-inflammatory effect. According to the findings, as concentration is raised, the formulation's anti-inflammatory activity rises. The formulation's percentage inhibition values are also equivalent to those of a typical anti-inflammatory medicine, indicating that it may be effective as a natural anti-inflammatory agent.
PubMed: 38882775
DOI: 10.4103/jpbs.jpbs_581_23 -
Environmental Science and Pollution... Jun 2024Salinity, resulting from various contaminants, is a major concern to global crop cultivation. Soil salinity results in increased osmotic stress, oxidative stress,... (Review)
Review
Salinity, resulting from various contaminants, is a major concern to global crop cultivation. Soil salinity results in increased osmotic stress, oxidative stress, specific ion toxicity, nutrient deficiency in plants, groundwater contamination, and negative impacts on biogeochemical cycles. Leaching, the prevailing remediation method, is expensive, energy-intensive, demands more fresh water, and also causes nutrient loss which leads to infertile cropland and eutrophication of water bodies. Moreover, in soils co-contaminated with persistent organic pollutants, heavy metals, and textile dyes, leaching techniques may not be effective. It promotes the adoption of microbial remediation as an effective and eco-friendly method. Common microbes such as Pseudomonas, Trichoderma, and Bacillus often struggle to survive in high-saline conditions due to osmotic stress, ion imbalance, and protein denaturation. Halophiles, capable of withstanding high-saline conditions, exhibit a remarkable ability to utilize a broad spectrum of organic pollutants as carbon sources and restore the polluted environment. Furthermore, halophiles can enhance plant growth under stress conditions and produce vital bio-enzymes. Halophilic microorganisms can contribute to increasing soil microbial diversity, pollutant degradation, stabilizing soil structure, participating in nutrient dynamics, bio-geochemical cycles, enhancing soil fertility, and crop growth. This review provides an in-depth analysis of pollutant degradation, salt-tolerating mechanisms, and plant-soil-microbe interaction and offers a holistic perspective on their potential for soil restoration.
PubMed: 38877191
DOI: 10.1007/s11356-024-33949-9 -
Food Chemistry Jun 2024This study aimed to explore how pulsed electric field (PEF) treatment affects the structural, physicochemical, and emulsification properties of porcine-derived...
Mechanisms underlying the changes in the structural, physicochemical, and emulsification properties of porcine myofibrillar proteins induced by prolonged pulsed electric field treatment.
This study aimed to explore how pulsed electric field (PEF) treatment affects the structural, physicochemical, and emulsification properties of porcine-derived myofibrillar proteins (MPs). Increasing PEF treatment induced partial polarization and protein unfolding, resulting in notable denaturation that affected both the secondary and tertiary structures. PEF treatment also improved the solubility and emulsification ability of MPs by reducing their pH and surface hydrophobicity. Confocal laser scanning microscopy confirmed the effective adsorption of MPs and PEF-treated MPs at the oil/water interface, resulting in well-fabricated Pickering emulsions. A weak particle network increased the apparent viscosity in short-term PEF-treated Pickering emulsions. Conversely, in emulsions with long-term PEF-treated MP, rheological variables decreased, and dispersion stability increased. These results endorse the potential application of PEF-treated porcine-derived MPs as efficient Pickering stabilizers, offering valuable insights into the creative use of PEF for enhancing high-quality meat products, meeting the increasing demand for clean-label choices.
PubMed: 38870818
DOI: 10.1016/j.foodchem.2024.140024 -
Biometals : An International Journal on... Jun 2024Schiff bases of existing antimicrobial drugs are an area, which is still to be comprehensively explored to improve drug efficiency against consistently resisting...
Schiff bases of existing antimicrobial drugs are an area, which is still to be comprehensively explored to improve drug efficiency against consistently resisting bacterial species. In this study, we have targeted a new and eco-friendly method of condensation reaction that allows the "green synthesis" as well as improved biological efficacy. The transition metal complexes of cefpodoxime with well-enhanced biological activities were synthesized. The condensation reaction product of cefpodoxime and vanillin was further reacted with suitable metal salts of [Mn (II), Cu (II), Fe (II), Zn (II), and Ni (II)] with 1:2 molar ratio (metal: ligand). The characterization of all the products were carried out by using UV-Visible, elemental analyzer, FTIR, H-NMR, ICP-OES, and LC-MS. Electronic data obtained by UV-Visible proved the octahedral geometry of metal complexes. The biological activities Schiff base ligand and its transition metal complexes were tested by using in-vitro anti-bacterial analysis against various Gram-negative, as well as Gram-positive bacterial strains. Proteinase and protein denaturation inhibition assays were utilized to evaluate the products in-vitro anti-inflammatory activities. The in vitro antioxidant activity of the ligand and its complexes was evaluated by utilizing the 2,2-diphenyl-1-picrylhydrazyl (DPPH) in-vitro method. The final results proved metal complexes to be more effective against bacterial microorganisms as compared to respective parent drug as well as their free ligands. Patch Dock, a molecular docking tool, was used to dock complexes 1a-5e with the crystal structure of GlcN-6-P synthase (ID: 1MOQ). According to the docking results, complex 2b exhibited a highest score (8,882; ACE = -580.43 kcal/mol) that is well correlated with a high inhibition as compared to other complexes which corresponds to the antibacterial screening outcomes.
PubMed: 38864936
DOI: 10.1007/s10534-024-00601-5 -
International Journal of Biological... Jun 2024Given the severe protein denaturation and self-aggregation during the high-temperature desolubilization, denatured soy meal (DSM) is limited by its low reactivity, high...
Given the severe protein denaturation and self-aggregation during the high-temperature desolubilization, denatured soy meal (DSM) is limited by its low reactivity, high viscosity, and poor water solubility. Preparing low-cost and high-performance adhesives with DSM as the key feedstock is still challenging. Herein, this study reveals a double-enzyme co-activation method targeting DSM with the glycosidic bonds in protein-carbohydrate complexes and partial amide bonds in protein, increasing the protein dispersion index from 10.2 % to 75.1 % improves the reactivity of DSM. The green crosslinker transglutaminase (TGase) constructs a robust adhesive isopeptide bond network with high water-resistant bonding strength comparable to chemical crosslinkers. The adhesive has demonstrated high dry/wet shear strength (2.56 and 0.93 MPa) for plywood. After molecular recombination by enzyme strategy, the adhesive had the proper viscosity, high reactivity, and strong water resistance. This research showcases a novel perspective on developing a DSM-based adhesive and blazes new avenues for changes in protein structural function and adhesive performance.
PubMed: 38862054
DOI: 10.1016/j.ijbiomac.2024.133054 -
Soft Matter Jun 2024Biogenic CaCO formation is regulated by crystallization proteins during crystal growth. Interactions of proteins with nascent mineral surfaces trigger proteins to be...
Biogenic CaCO formation is regulated by crystallization proteins during crystal growth. Interactions of proteins with nascent mineral surfaces trigger proteins to be incorporated into the crystal lattice. As a result of incorporation, these intracrystalline proteins are protected in the lattice, an example of which is ancient eggshell proteins that have persisted in CaCO for thousands of years even under harsh environmental conditions. OC17 is an eggshell protein known to interact with CaCO during eggshell formation during which OC17 becomes incorporated into the lattice. Understanding protein incorporation into CaCO could offer insights into protein stability inside crystals. Here, we study the protection of OC17 in the CaCO lattice. Using thermogravimetric analysis we show that the effect of temperature on intracrystalline proteins of eggshells is negligible below 250 °C. Next, we show that lattice incorporation protects the OC17 structure despite a heat-treatment step that is shown to denature the protein. Because incorporated proteins need to be released from crystals, we verify metal chelation as a safe crystal dissolution method to avoid protein denaturation during reconstitution. Finally, we optimize the recombinant expression of OC17 which could allow engineering OC17 for engineered intracrystalline entrapment studies.
Topics: Calcium Carbonate; Egg Proteins; Crystallization; Animals; Temperature
PubMed: 38860646
DOI: 10.1039/d4sm00371c