RESUMO
Bioresorbable chitosan scaffolds have shown potential for osteochondral repair applications. Thein vivodegradation of chitosan, mediated by lysozyme and releasing glucosamine, enables progressive replacement by ingrowing tissue. Here the degradation process of a chitosan-nHA based bioresorbable scaffold was investigated for mass loss, mechanical properties and degradation products released from the scaffold when subjected to clinically relevant enzyme concentrations. The scaffold showed accelerated mass loss during the early stages of degradation but without substantial reduction in mechanical strength or structure deterioration. Although not cytotoxic, the medium in which the scaffold was degraded for over 2 weeks showed a transient decrease in mesenchymal stem cell viability, and the main degradation product (glucosamine) demonstrated a possible adverse effect on viability when added at its peak concentration. This study has implications for the design and biomedical application of chitosan scaffolds, underlining the importance of modelling degradation products to determine suitability for clinical translation.
Assuntos
Sobrevivência Celular , Quitosana , Teste de Materiais , Células-Tronco Mesenquimais , Engenharia Tecidual , Alicerces Teciduais , Quitosana/química , Sobrevivência Celular/efeitos dos fármacos , Alicerces Teciduais/química , Células-Tronco Mesenquimais/citologia , Animais , Engenharia Tecidual/métodos , Materiais Biocompatíveis/química , Células Cultivadas , Glucosamina/química , Humanos , Muramidase/química , Implantes AbsorvíveisRESUMO
Inspired by the unique functionalities of biomolecular membraneless organelles (MLOs) formed via liquid-liquid phase separation (LLPS) of intrinsically disordered proteins (IDPs) and nucleic acids, a great deal of effort has been devoted to devising phase-separated artificial subcellular dynamic compartments. These endeavors aim to unravel the molecular mechanism underlying the formation and intracellular delivery of susceptible macromolecular therapeutics. We report herein pyroglutamic acid (PGA)-based well-defined homopolymers featuring stimuli-tunable reversible self-coacervation ability. The polymer exhibits an upper critical solution temperature (UCST) transition in aqueous solutions and has the propensity to undergo cooling-induced LLPS, producing micrometer-sized liquid droplets. This phase separation phenomenon could be modulated by various factors, including polymer concentration, chain length, solution pH, and types and concentrations of different additives. These micrometer droplets are thermally reversible and encapsulate a wide variety of cargoes, including small hydrophobic fluorescent molecules, hydrophilic anticancer drugs, and fluorophore-labeled macromolecular proteins (bovine serum albumin and lysozyme). The payloads were released by exploiting the thermo/pH-mediated disassembly behavior of the coacervates, preserving the bioactivity of the sensitive therapeutics. This environmentally responsive, simple yet versatile artificial MLO model system will provide insights into the biomolecular nonionic condensates and pave the way for the de novo design of dynamic biomolecule depots.
Assuntos
Ligação de Hidrogênio , Humanos , Soroalbumina Bovina/química , Muramidase/química , Ácido Poliglutâmico/química , Ácido Poliglutâmico/análogos & derivados , Antineoplásicos/química , Concentração de Íons de Hidrogênio , Liberação Controlada de Fármacos , Temperatura , Polímeros/química , Interações Hidrofóbicas e HidrofílicasRESUMO
Lysozymes are hydrolytic enzymes, and they are ubiquitous among all living organisms. They are mostly associated with antibacterial properties through their muramidase activity, while other properties such as iso-peptidase activity are also common. Invertebrate-type (i-type) lysozymes include the enzyme Destabilase, which is present in the salivary secretions of the medicinal leach Hirundo medicinalis. Destabilase has the ability to hydrolyse the ε-(γ-glutamyl)-lysine iso-peptide bonds formed by transglutaminase in fibrin of vertebrate blood, thereby destabilising blood clots. We have identified an i-type lysozyme from the hemocytes of the freshwater crayfish Pacifastacus leniusculus, which was found to be upregulated at the protein level in response to an injection of the ß-1,3-glucan laminarin. Based on its sequence we predicted that this lysozyme would lack muramidase activity, and therefore we decided to determine its putative immune function. The P. leniusculus i-type lysozyme (Pl-ilys), is a protein with 159 amino acid residues, including a 29 residue signal peptide, with a predicted molecular weight of 16 kDa and a predicted pI of 5.6. It is expressed primarily in the hemocytes and to a lesser extent in the hematopoietic tissue. A recombinant mature Pl-ilys using an E. coli expression system was produced, and we could ascertain that this enzyme was deficient of muramidase activity. Moreover, no iso-peptidase activity could be detected against the substrate l-γ-glutamine-p-nitroanilide. Analysis of the conserved domains in Pl-ilys showed a putative destabilase domain, and thus we tested the clot dissolving activity of this enzyme. We could show that the purified P. leniusculus clotting protein which had been coagulated and clotted with transglutaminase was dissolved by the addition of Pl-ilys. Taken together our results indicate that Pl-ilys has a clot dissolving or destabilising activity in crustacean blood.
Assuntos
Proteínas de Artrópodes , Astacoidea , Muramidase , Animais , Muramidase/imunologia , Muramidase/metabolismo , Muramidase/química , Muramidase/genética , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/imunologia , Proteínas de Artrópodes/química , Astacoidea/imunologia , Astacoidea/genética , Sequência de Aminoácidos , Filogenia , Alinhamento de Sequência/veterinária , Imunidade Inata , Hemócitos/imunologia , Sequência de Bases , Coagulação Sanguínea/efeitos dos fármacos , Perfilação da Expressão Gênica/veterináriaRESUMO
One of the main interests in the food industry is the preservation of food from spoilage by microorganisms or lipid oxidation. A novel alternative is the development of additives of natural origin with dual activity. In the present study, a chemically modified lysozyme (Lys) with epigallocatechin gallate (EGCG) was developed to obtain a conjugate (Lys-EGCG) with antibacterial/antioxidant activity to improve its properties and increase its application potential. The modification reaction was carried out using a free radical grafting method for the Lys modification reaction, using ascorbic acid and hydrogen peroxide as radical initiators in an aqueous medium. The synthesis of Lys-EGCG conjugate was confirmed by spectroscopic (FT-IR, 1H-RMN, and XPS) and calorimetry differential scanning (DSC) analyses. The EGCG binding to the Lys biomolecule was quantified by the Folin-Ciocalteu method; the antibacterial activity was evaluated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MCB) against Staphylococcus aureus and Pseudomonas fluorescens; the antioxidant activity was evaluated by ABTS, DPPH, and FRAP. The spectroscopic results showed that the Lys-EGCG conjugate was successfully obtained, and the DSC analysis revealed a 20 °C increase (P < 0.05) in the denaturation temperature of Lys due to EGCG modification. The EGCG concentration in Lys-EGCG was 97.97 ± 4.7 µmol of EGCG/g of sample. The antibacterial and antioxidant activity of the Lys-EGCG conjugate was higher (P < 0.05) than pure EGCG and Lys. The chemical modification of Lys with EGCG allows for the bioconjugate with a dual function (antibacterial/antioxidant), broadening the range of Lys and EGCG applications to different areas such as food, cosmetic, and pharmaceutical industries.
Assuntos
Antibacterianos , Antioxidantes , Catequina , Testes de Sensibilidade Microbiana , Muramidase , Pseudomonas fluorescens , Staphylococcus aureus , Catequina/análogos & derivados , Catequina/química , Catequina/farmacologia , Muramidase/farmacologia , Muramidase/química , Muramidase/metabolismo , Antioxidantes/farmacologia , Antioxidantes/química , Antibacterianos/farmacologia , Antibacterianos/química , Staphylococcus aureus/efeitos dos fármacos , Pseudomonas fluorescens/efeitos dos fármacosRESUMO
Human lysozyme undergoes a phase-separation process to form insoluble amyloid-architects that cause several pathologies including systemic amyloidosis. Here we have tailored 6-gingerol by extending its molecular framework with active functional groups to specifically target lysozyme phase-transition events. Aggregation assay revealed that tailored 6-gingerol with 4-aromatic moieties (MTV4) substantially suppressed the conversion of the lysozyme low-density liquid phase (LDLP) to solid-phase structured amyloids. The data obtained from biophysical, computational, and microscopic imaging tools suggest direct intervention of MTV4 with the liquid-liquid phase separation. The CD data suggest that MTV4 was able to retain the native conformation of lysozyme. Both biomolecular and computational data reveal the interference of MTV4 with the aggregation-prone hydrophobic stretches within the lysozyme, thereby retaining the native structure and reversing the misfolded intermediates to active monomers. Also, MTV4 was able to induce rapid dissolution of preformed-toxic amyloid fibrils. These results reinforce the importance of the aromatic-aromatic interaction in preventing human lysozyme phase separation.
Assuntos
Amiloide , Catecóis , Álcoois Graxos , Muramidase , Muramidase/química , Muramidase/metabolismo , Álcoois Graxos/química , Humanos , Catecóis/química , Amiloide/química , Amiloide/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Estrutura Molecular , Transição de Fase , Agregados Proteicos , Separação de FasesRESUMO
Gas cluster ion beam (GCIB)-assisted deposition is used to build multilayered protein-based structures. In this process, Ar3000-5000+ clusters bombard and sputter molecules from a reservoir (target) to a collector, an operation that can be sequentially repeated with multiple targets. The process occurs under a vacuum, making it adequate for further sample conservation in the dry state, since many proteins do not have long-term storage stability in the aqueous state. First of all, the stability in time and versatility in terms of molecule selection are demonstrated with the fabrication of peptide multilayers featuring a clear separation. Then, lysozyme and trypsin are used as protein models to show that the activity remaining on the collector after deposition is linearly proportional to the argon ion dose. The energy per atom (E/n) of the Ar clusters is a parameter that was also changed for lysozyme deposition, and its increase negatively affects activity. The intact detection of larger protein molecules by SDS-PAGE gel electrophoresis and a bioassay (trypsin at ≈25 kDa and glucose oxidase (GOx) at ≈80 kDa) is demonstrated. Finally, GOx and horseradish peroxidase, two proteins involved in the same enzymatic cascade, are successively deposited on ß-d-glucose to build an on-demand release material in which the enzymes and the substrate (ß-d-glucose) are combined in a dry trilayer, and the reaction occurs only upon reintroduction in aqueous medium.
Assuntos
Glucose Oxidase , Peroxidase do Rábano Silvestre , Muramidase , Tripsina , Muramidase/química , Muramidase/metabolismo , Glucose Oxidase/química , Glucose Oxidase/metabolismo , Tripsina/química , Tripsina/metabolismo , Peroxidase do Rábano Silvestre/química , Peroxidase do Rábano Silvestre/metabolismo , Peptídeos/química , Animais , Glucose/químicaRESUMO
The hallmark of amyloidosis, such as Alzheimer's disease and Parkinson's disease, is the deposition of amyloid fibrils in various internal organs. The onset of the disease is related to the strength of cytotoxicity caused by toxic amyloid species. Furthermore, amyloid fibrils show polymorphism, where some types of fibrils are cytotoxic while others are not. It is thus essential to understand the molecular mechanism of cytotoxicity, part of which is caused by the interaction between amyloid polymorphic fibrils and cell membranes. Here, using amyloid polymorphs of hen egg white lysozyme, which is associated with hereditary systemic amyloidosis, showing different levels of cytotoxicity and liposomes of DMPC and DMPG, changes in the secondary structure of the polymorphs and the structural state of phospholipid membranes caused by the interaction were investigated using vacuum-ultraviolet circular dichroism (VUVCD) and Laurdan fluorescence measurements, respectively. Analysis has shown that the more cytotoxic polymorph increases the antiparallel ß-sheet content and causes more disorder in the membrane structure while the other less cytotoxic polymorph shows the opposite structural changes and causes less structural disorder in the membrane. These results suggest a close correlation between the structural properties of amyloid fibrils and the degree of structural disorder of phospholipid membranes, both of which are involved in the fundamental process leading to amyloid cytotoxicity.
Assuntos
Amiloide , Dicroísmo Circular , Muramidase , Fosfolipídeos , Muramidase/química , Muramidase/metabolismo , Amiloide/química , Fosfolipídeos/química , Animais , Estrutura Secundária de Proteína , Dimiristoilfosfatidilcolina/química , Fosfatidilgliceróis/química , Lipossomos/química , Galinhas , VácuoRESUMO
Lysozyme, a well-known bacteriolytic enzyme, exhibits a fascinating yet complex behavior when it comes to protein aggregation. Under certain conditions, this enzyme undergoes flexible transformation, transitioning from partially unfolded intermediate units of native conformers into complex cross-ß-rich nano fibrillar amyloid architectures. Formation of such lysozyme amyloids has been implicated in a multitude of pathological and medical severities, like hepatic dysfunction, hepatomegaly, splenic rupture as well as spleen dysfunction, nephropathy, sicca syndrome, renal dysfunction, renal amyloidosis, and systemic amyloidosis. In this comprehensive review, we have attempted to provide in-depth insights into the aggregating behavior of lysozyme across a spectrum of variables, including concentrations, temperatures, pH levels, and mutations. Our objective is to elucidate the underlying mechanisms that govern lysozyme's aggregation process and to unravel the complex interplay between its structural attributes. Moreover, this work has critically examined the latest advancements in the field, focusing specifically on novel strategies and systems, that have been implemented to delay or inhibit the lysozyme amyloidogenesis. Apart from this, we have tried to explore and advance our fundamental understanding of the complex processes involved in lysozyme aggregation. This will help the research community to lay a robust foundation for screening, designing, and formulating targeted anti-amyloid therapeutics offering improved treatment modalities and interventions not only for lysozyme-linked amyloidopathy but for a wide range of amyloid-related disorders.
Assuntos
Amiloide , Muramidase , Nanoestruturas , Transição de Fase , Muramidase/química , Muramidase/metabolismo , Amiloide/química , Amiloide/metabolismo , Amiloide/antagonistas & inibidores , Humanos , Nanoestruturas/química , Animais , Amiloidose/metabolismo , Amiloidose/patologia , Amiloidose/tratamento farmacológicoRESUMO
Under the influence of various conditions, misfolding of soluble proteins occurs, leading to the formation of toxic insoluble amyloids. The formation and deposition of such amyloids within the body are associated with detrimental biological consequences such as the onset of several amyloid-related diseases. Previously, we established a strategy for the rational design of peptide inhibitors against amyloid formation based on the amyloidogenic-prone region of the protein. In the current study, we have designed and identified an Asp-containing rationally designed hexapeptide (SqP4) as an excellent inhibitor of hen egg-white lysozyme (HEWL) amyloid progression in vitro. First, SqP4 showed strong affinity toward the native monomeric HEWL leading to the stabilization of the native form and restriction in the unfolding process of monomeric HEWL. Second, SqP4 was found to arrest the amyloidogenic misfolded structure of HEWL in a nonfibrillar monomer-like stage. We also observed the differential effect of the protonation state of the charged amino acid (Asp) within the peptide inhibitor on the amyloid formation of HEWL and explored the reason behind the observations. The findings of this study can be implemented in future strategies for the development of potent therapeutics against other amyloid-related diseases.
Assuntos
Muramidase , Prótons , Muramidase/química , Muramidase/metabolismo , Animais , Amiloide/química , Amiloide/antagonistas & inibidores , Amiloide/metabolismo , Galinhas , Peptídeos/química , Peptídeos/farmacologia , Peptídeos/síntese química , Dobramento de ProteínaRESUMO
The effects of two macromolecular cosolutes, specifically the polysaccharide dextran-20 and the protein lysozyme, on the aggregation kinetics of a pathogenic huntingtin exon-1 protein (hhtex1) with a 35 polyglutamine repeat, httex1Q35, are described. A unified kinetic model that establishes a direct connection between reversible tetramerization occurring on the microsecond time scale and irreversible fibril formation on a time scale of hours/days forms the basis for quantitative analysis of httex1Q35 aggregation, monitored by measuring cross-peak intensities in a series of 2D 1H-15N NMR correlation spectra acquired during the course of aggregation. The primary effects of the two cosolutes are associated with shifts in the prenucleation tetramerization equilibrium resulting in substantial changes in concentration of "preformed" httex1Q35 tetramers. Similar effects of the two cosolutes on the tetramerization equilibrium observed for a shorter, nonaggregating huntingtin variant with a 7-glutamine repeat, httex1Q7, lend confidence to the conclusions drawn from the fits to the httex1Q35 aggregation kinetics.
Assuntos
Proteína Huntingtina , Muramidase , Proteína Huntingtina/química , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Cinética , Muramidase/química , Muramidase/metabolismo , Humanos , Dextranos/química , Peptídeos/química , Ressonância Magnética Nuclear Biomolecular , Agregados Proteicos/efeitos dos fármacos , Substâncias Macromoleculares/química , Multimerização Proteica/efeitos dos fármacos , Espectroscopia de Ressonância MagnéticaRESUMO
Lysozyme (LYZ) plays a crucial role in the body's immune defense system. Monitoring LYZ levels can provide valuable insights into the diagnosis and severity assessment of various diseases. Traditionally, antibody-based sandwich assays are employed for LYZ detection, but they are often time-consuming and operationally complicated. In this research, a novel sandwich FRET biosensor was developed, which enables rapid detection of LYZ based on peptide-functionalized gold nanoparticles (pAuNPs) and FAM-labeled aptamer (Apt-FAM). Initially, a mixture of Apt-FAM and pAuNPs resulted in partial quenching of the Apt-FAM fluorescence emission through an inner filter effect (IFE), with negligible energy transfer because of the electrostatic repulsion between the negatively charged pAuNPs and Apt-FAM. The introduction of LYZ into the mixture drove the specific binding of Apt-FAM and pAuNPs to LYZ, facilitating the formation of a pAuNPs-LYZ-aptamer sandwich structure. The formation of this complex drew the pAuNPs and Apt-FAM into close enough proximity to enable FRET to occur, which in turn effectively quenched the fluorescence emission of FAM. The decrease in FAM fluorescence intensity was correlated with the increasing concentration of LYZ. Thus, a sandwich FRET biosensor was successfully developed for LYZ detection with a linear detection range of 0-1.75 µM and a detection limit of 85 nM. Additionally, the biosensor allowed visual detection of LYZ in a 96-well microplate, with a rapid response time of just 15 s. This study introduces a innovative sandwich FRET biosensor that combines aptamer and peptide recognition elements, offering a fast and antibody-free method for protein detection.
Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Transferência Ressonante de Energia de Fluorescência , Ouro , Nanopartículas Metálicas , Muramidase , Peptídeos , Ouro/química , Transferência Ressonante de Energia de Fluorescência/métodos , Muramidase/análise , Muramidase/química , Nanopartículas Metálicas/química , Técnicas Biossensoriais/métodos , Aptâmeros de Nucleotídeos/química , Peptídeos/química , Limite de Detecção , Corantes Fluorescentes/química , RodaminasRESUMO
The reactivity of the anticancer drug picoplatin (cis-amminedichlorido(2-methylpyridine)platinum(II) complex) with the model proteins hen egg white lysozyme (HEWL) and bovine pancreatic ribonuclease (RNase A) was investigated by electrospray ionisation mass spectrometry (ESI MS) and X-ray crystallography. The data were compared with those previously obtained for the adducts of these proteins with cisplatin, carboplatin and oxaliplatin under the same experimental conditions. ESI-MS data show binding of Pt to both proteins, with fragments retaining the 2-methylpyridine ligand and, possibly, a chloride ion. X-ray crystallography identifies different binding sites on the two proteins, highlighting a different behaviour of picoplatin in the absence or presence of dimethyl sulfoxide (DMSO). Metal-containing fragments bind to HEWL close to the side chains of His15, Asp18, Asp119 and both Lys1 and Glu7, whereas they bind to RNase A on the side chain of His12, Met29, His48, Asp53, Met79, His105 and His119. The data suggest that the presence of DMSO favours the loss of 2-methylpyridine and alters the ability of the Pt compound to bind to the two proteins. With both proteins, picoplatin appears to behave similarly to cisplatin and carboplatin when dissolved in DMSO, whereas it behaves more like oxaliplatin in the absence of the coordinating solvent. This study provides important insights into the pharmacological profile of picoplatin and supports the conclusion that coordinating solvents should not be used to evaluate the biological activities of Pt-based drugs.
Assuntos
Muramidase , Compostos Organoplatínicos , Ribonuclease Pancreático , Muramidase/química , Muramidase/metabolismo , Ribonuclease Pancreático/química , Ribonuclease Pancreático/metabolismo , Animais , Cristalografia por Raios X , Compostos Organoplatínicos/química , Compostos Organoplatínicos/metabolismo , Bovinos , Ligação Proteica , Sítios de Ligação , Modelos Moleculares , Galinhas , Espectrometria de Massas por Ionização por Electrospray , Dimetil Sulfóxido/química , Carboplatina/química , Carboplatina/metabolismoRESUMO
Micro- and nano-plastics (NPs) are found in human milk, blood, tissues, and organs and associate with aberrant health outcomes including inflammation, genotoxicity, developmental disorders, onset of chronic diseases, and autoimmune disorders. Yet, interfacial interactions between plastics and biomolecular systems remain underexplored. Here, we have examined experimentally, in vitro, in vivo, and by computation, the impact of polystyrene (PS) NPs on a host of biomolecular systems and assemblies. Our results reveal that PS NPs essentially abolished the helix-content of the milk protein ß-lactoglobulin (BLG) in a dose-dependent manner. Helix loss is corelated with the near stoichiometric formation of ß-sheet elements in the protein. Structural alterations in BLG are also likely responsible for the nanoparticle-dependent attrition in binding affinity and weaker on-rate constant of retinol, its physiological ligand (compromising its nutritional role). PS NP-driven helix-to-sheet conversion was also observed in the amyloid-forming trajectory of hen egg-white lysozyme (accelerated fibril formation and reduced helical content in fibrils). Caenorhabditis elegans exposed to PS NPs exhibited a decrease in the fluorescence of green fluorescent protein-tagged dopaminergic neurons and locomotory deficits (akin to the neurotoxin paraquat exposure). Finally, in silico analyses revealed that the most favorable PS/BLG docking score and binding energies corresponded to a pose near the hydrophobic ligand binding pocket (calyx) of the protein where the NP fragment was found to make nonpolar contacts with side-chain residues via the hydrophobic effect and van der Waals forces, compromising side chain/retinol contacts. Binding energetics indicate that PS/BLG interactions destabilize the binding of retinol to the protein and can potentially displace retinol from the calyx region of BLG, thereby impairing its biological function. Collectively, the experimental and high-resolution in silico data provide new insights into the mechanism(s) by which PS NPs corrupt the bimolecular structure and function, induce amyloidosis and onset neuronal injury, and drive aberrant physiological and behavioral outcomes.
Assuntos
Caenorhabditis elegans , Lactoglobulinas , Muramidase , Animais , Muramidase/química , Muramidase/metabolismo , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Caenorhabditis elegans/metabolismo , Poliestirenos/química , Nanopartículas/química , Vitamina A/química , Vitamina A/metabolismo , Humanos , Homeostase/efeitos dos fármacos , Plásticos/químicaRESUMO
Carbon dots (CDs) are carbon nano materials (CNMs) that find use across several biological applications because of their water solubility, biocompatible nature, eco-friendliness, and ease of synthesis. Additionally, their physiochemical properties can be chemically tuned for further optimization towards specific applications. Here, we investigate the efficacy of C70-derived Graphene Acid Quantum Dots (GAQDs) in mitigating the transformation of soluble, monomeric Hen Egg-White Lysozyme (HEWL) to mature fibrils during its amyloidogenic trajectory. Our findings reveal that GAQDs exhibit dose-dependent inhibition of HEWL fibril formation (up to 70 % at 5 mg/mL) without affecting mitochondrial membrane potential or inducing apoptosis at the same density. Furthermore, GAQDs scavenged reactive oxygen species (ROS); achieving a 50 % reduction in ROS levels at a mere 100 µg/mL when exposed to a standard free radical generator. GAQDs were not only found to be biocompatible with a human neuroblastoma-derived SHSY-5Y cell line but also rescued the cells from rotenone-induced apoptosis. The GAQD-tolerance of SHSY-5Y cells coupled with their ability to restitute cells from rotenone-dependent apoptosis, when taken in conjunction with the biocompatibility data, indicate that GAQDs possess neuroprotective potential. The data position this class of CNMs as promising candidates for resolving aberrant cellular outputs that associate with the advent and progress of multifactorial neurodegenerative disorders including Parkinson's (PD) and Alzheimer's diseases (AD) wherein environmental causes are implicated (95 % etiology). The data suggest that GAQDs are a multifunctional carbon-based sustainable nano-platform at the intersection of nanotechnology and neuroprotection for advancing green chemistry-derived, sustainable healthcare solutions.
Assuntos
Apoptose , Grafite , Muramidase , Pontos Quânticos , Espécies Reativas de Oxigênio , Pontos Quânticos/química , Humanos , Grafite/química , Grafite/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Muramidase/química , Muramidase/metabolismo , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/metabolismo , Animais , Tamanho da Partícula , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/química , Carbono/química , Propriedades de Superfície , Potencial da Membrana Mitocondrial/efeitos dos fármacosRESUMO
Bioconjugation of polymers to proteins is a method to impart improved stability and pharmacokinetic properties to biologic systems. However, the precise effects of polymer architecture on the resulting bioconjugates are not well understood. Particularly, cyclic polymers are known to possess unique features such as a decreased hydrodynamic radius when compared to their linear counterparts of the same molecular weight, but have not yet been studied. Here, we report the first bioconjugation of a cyclic polymer, poly(ethylene glycol) (PEG), to a model protein, T4 lysozyme, containing a single engineered cysteine residue (V131C). We compare the stability and activity of this conjugate with those of a linear PEG-T4 lysozyme analogue of similar molecular weight. Furthermore, we used molecular dynamics (MD) simulations to determine the behavior of the polymer-protein conjugates in solution. We introduce cyclic polymer-protein conjugates as potential candidates for the improvement of biologic therapeutics.
Assuntos
Simulação de Dinâmica Molecular , Muramidase , Polietilenoglicóis , Polietilenoglicóis/química , Muramidase/química , Bacteriófago T4/enzimologiaRESUMO
We introduce a novel and straightforward methodology for photoredox arylation of an indole scaffold using aryldiazonium salts under mild and metal-free conditions. Our approach enables the regioselective and chemoselective introduction of several aryl groups to the C(2) position of indoles and tryptophan, even in competition with other amino acids. This approach extends to the late-stage functionalization of peptides and lysozyme, heralding the unprecedented arylation of tryptophan residues in wild-type proteins and offering broad utility in chemical biology.
Assuntos
Indóis , Oxirredução , Triptofano , Triptofano/química , Indóis/química , Estrutura Molecular , Processos Fotoquímicos , Muramidase/química , Peptídeos/química , Estereoisomerismo , CatáliseRESUMO
Cyclometallated Pt(II) complexes possessing hydrophobic 2-phenylpyridine (ppy) ligands and hydrophilic acetonylacetone (acac) ligands have been investigated for their ability to detect amyloid fibrils via luminescence response. Using hen egg-white lysozyme (HEWL) as a model amyloid protein, Pt(II) complexes featuring benzanilide-substituted ppy ligands and ethylene glycol-functionalized acac ligands demonstrated enhanced luminescence in the presence of HEWL fibrils, whereas Pt(II) complexes lacking complementary hydrophobic/hydrophilic ligand sets displayed little to no emission enhancement. An amphiphilic Pt(II) complex incorporating a bis(ethylene glycol)-derivatized acac ligand was additionally found to trigger restructuring of HEWL fibrils into smaller spherical aggregates. Amphiphilic Pt(II) complexes were generally non-toxic to SH-SY5Y neuroblastoma cells, and several complexes also exhibited enhanced luminescence in the presence of Aß42 fibrils associated with Alzheimer's disease. This study demonstrates that easily prepared and robust (ppy)PtII(acac) complexes show promising reactivity toward amyloid fibrils and represent attractive molecular scaffolds for design of small-molecule probes targeting amyloid assemblies.
Assuntos
Amiloide , Muramidase , Humanos , Amiloide/química , Amiloide/metabolismo , Muramidase/química , Muramidase/metabolismo , Linhagem Celular Tumoral , Complexos de Coordenação/química , Complexos de Coordenação/síntese química , Luminescência , Peptídeos beta-Amiloides/metabolismo , Peptídeos beta-Amiloides/química , Animais , Interações Hidrofóbicas e Hidrofílicas , Agregados Proteicos/efeitos dos fármacos , Platina/química , Compostos Organoplatínicos/química , Compostos Organoplatínicos/farmacologia , Compostos Organoplatínicos/síntese química , Ligantes , Tensoativos/química , Tensoativos/síntese químicaRESUMO
An assay that integrates histidine-rich peptides (HisRPs) with high-affinity aptamers was developed enabling the specific and sensitive determination of the target lysozyme. The enzyme-like activity of HisRP is inhibited by its interaction with a target recognized by an aptamer. In the presence of the target, lysozyme molecules progressively assemble on the surface of HisRP in a concentration-dependent manner, resulting in the gradual suppression of enzyme-like activity. This inhibition of HisRP's enzyme-like activity can be visually observed through color changes in the reaction product or quantified using UV-visible absorption spectroscopy. Under optimal conditions, the proposed colorimetric assay for lysozyme had a detection limit as low as 1 nM and exhibited excellent selectivity against other nonspecific interferents. Furthermore, subsequent research validated the practical applicability of the developed colorimetric approach to saliva samples, indicating that the assay holds significant potential for the detection of lysozymes in samples derived from humans.
Assuntos
Colorimetria , Muramidase , Saliva , Muramidase/análise , Muramidase/química , Muramidase/metabolismo , Colorimetria/métodos , Humanos , Saliva/química , Saliva/enzimologia , Limite de Detecção , Peptídeos/química , Aptâmeros de Nucleotídeos/química , Proteínas/análise , Técnicas Biossensoriais/métodos , Histidina/análise , Histidina/químicaRESUMO
Biocompatible nanoparticles as drug carriers can improve the therapeutic efficiency of hydrophobic drugs. However, the synthesis of biocompatible and biodegradable polymeric nanoparticles can be time-consuming and often involves toxic solvents. Here, a simple method for protein-based stable drug-loaded particles with a narrow polydispersity is introduced. In this process, lysozyme is mixed with hydrophobic drugs (curcumin, ellipticine, and dasatinib) and fructose to prepare lysozyme-based drug particles of around 150 nm in size. Fructose is mixed with the drug to generate nanoparticles that serve as templates for the lysozyme coating. The effect of lysozyme on the physicochemical properties of these nanoparticles is studied by transmission electron microscopy (TEM) and scattering techniques (e.g., dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS)). We observed that lysozyme significantly stabilized the curcumin fructose particles for 7 days. Moreover, additional drugs, such as ellipticine and dasatinib, can be loaded to form dual-drug particles with narrow polydispersity and spherical morphology. The results also reveal that lysozyme dual ellipticine/dasatinib curcumin particles enhance the cytotoxicity and uptake on MCF-7 cells, RAW 264.7 cells, and U-87 MG cells due to the larger and rigid hydrophobic core. In summary, lysozyme in combination with fructose and curcumin can serve as a powerful combination to form protein-based stable particles for the delivery of hydrophobic drugs.
Assuntos
Curcumina , Dasatinibe , Portadores de Fármacos , Elipticinas , Muramidase , Nanopartículas , Muramidase/química , Muramidase/metabolismo , Nanopartículas/química , Curcumina/química , Curcumina/farmacologia , Animais , Humanos , Camundongos , Portadores de Fármacos/química , Dasatinibe/química , Dasatinibe/farmacologia , Elipticinas/química , Elipticinas/farmacologia , Células RAW 264.7 , Células MCF-7 , Tamanho da Partícula , Frutose/química , Interações Hidrofóbicas e Hidrofílicas , Sobrevivência Celular/efeitos dos fármacos , Linhagem Celular TumoralRESUMO
Two of the deadliest infectious diseases, COVID-19 and tuberculosis (TB), have combined to establish a worldwide pandemic, wreaking havoc on economies and claiming countless lives. The optimised, multitargeted medications may diminish resistance and counter them together. Based on computational expression studies, 183 genes were co-expressed in COVID-19 and TB blood samples. We used the multisampling screening algorithms on the top ten co-expressed genes (CD40, SHP2, Lysozyme, GATA3, cCBL, SIVmac239 Nef, CD69, S-adenosylhomocysteinase, Chemokine Receptor-7, and Membrane Protein). Imidurea is a multitargeted inhibitor for COVID-19 and TB, as confirmed by extensive screening and post-filtering utilising MM\GBSA algorithms. Imidurea has shown docking and MM\GBSA scores of -8.21 to -4.75 Kcal/mol and -64.16 to -29.38 Kcal/mol, respectively. The DFT, pharmacokinetics, and interaction patterns suggest that Imidurea may be a drug candidate, and all ten complexes were tested for stability and bond strength using 100 ns for all MD atoms. The modelling findings showed the complex's repurposing potential, with a cumulative deviation and fluctuation of <2 Å and significant intermolecular interaction, which validated the possibilities. Finally, an inhibition test was performed to confirm our in-silico findings on SARS-CoV-2 Delta variant infection, which was suppressed by adding imidurea to Vero E6 cells after infection.