Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 9.040
Filter
1.
Carbohydr Polym ; 339: 122251, 2024 Sep 01.
Article in English | MEDLINE | ID: mdl-38823918

ABSTRACT

In this study, the disulfide-linked hyaluronic acid (HA) hydrogels were optimised for potential application as a scaffold in tissue engineering through the Quality by Design (QbD) approach. For this purpose, HA was first modified by incorporating the cysteine moiety into the HA backbone, which promoted the formation of disulfide cross-linked HA hydrogel at physiological pH. Utilising a Design of Experiments (DoE) methodology, the critical factors to achieve stable biomaterials, i.e. the degree of HA substitution, HA molecular weight, and coupling agent ratio, were explored. To establish a design space, the DoE was performed with 65 kDa, 138 kDa and 200 kDa HA and variable concentrations of coupling agent to optimise conditions to obtain HA hydrogel with improved rheological properties. Thus, HA hydrogel with a 12 % degree of modification, storage modulus of ≈2321 Pa and loss modulus of ≈15 Pa, was achieved with the optimum ratio of coupling agent. Furthermore, biocompatibility assessments in C28/I2 chondrocyte cells demonstrated the non-toxic nature of the hydrogel, underscoring its potential for tissue regeneration. Our findings highlight the efficacy of the QbD approach in designing HA hydrogels with tailored properties for biomedical applications.


Subject(s)
Biocompatible Materials , Chondrocytes , Disulfides , Hyaluronic Acid , Hydrogels , Rheology , Tissue Engineering , Hyaluronic Acid/chemistry , Hydrogels/chemistry , Hydrogels/chemical synthesis , Disulfides/chemistry , Chondrocytes/drug effects , Chondrocytes/cytology , Biocompatible Materials/chemistry , Biocompatible Materials/chemical synthesis , Tissue Engineering/methods , Tissue Scaffolds/chemistry , Animals , Cell Line , Cell Survival/drug effects , Humans , Hydrogen-Ion Concentration
2.
Mikrochim Acta ; 191(7): 367, 2024 Jun 04.
Article in English | MEDLINE | ID: mdl-38832980

ABSTRACT

An electrochemical aptasensor was used for the fast and sensitive detection of zearalenone (ZEN) based on the combination of Co3O4/MoS2/Au nanocomposites and the hybrid chain reaction (HCR). The glassy carbon electrode was coated with Co3O4/MoS2/Au nanomaterials to immobilize the ZEN-cDNA that had been bound with ZEN-Apt by the principle of base complementary pairing. In the absence of ZEN, the HCR could not be triggered because the ZEN-cDNA could not be exposed. After ZEN was added to the surface of the electrode, a complex structure was produced on the modified electrode by the combination of ZEN and ZEN-Apt. Therefore, the ZEN-cDNA can raise the HCR to produce the long-strand dsDNA structure. Due to the formation of dsDNA, the methylene blue (MB) could be inserted into the superstructure of branched DNA and the peak currents of the MB redox signal dramatically increased. So the concentration of ZEN could be detected by the change of signal intensity. Under optimized conditions, the developed electrochemical biosensing strategy showed an outstanding linear detection range of 1.0×10-10 mol/L to 1.0×10-6 mol/L, a low detection limit (LOD) of 8.5×10-11 mol/L with desirable selectivity and stability. Therefore, the fabricated platform possessed a great application potential in fields of food safety, medical detection, and drug analysis.


Subject(s)
Aptamers, Nucleotide , Biosensing Techniques , Cobalt , Disulfides , Electrochemical Techniques , Gold , Limit of Detection , Molybdenum , Nanocomposites , Oxides , Zearalenone , Zearalenone/analysis , Zearalenone/chemistry , Gold/chemistry , Nanocomposites/chemistry , Electrochemical Techniques/methods , Aptamers, Nucleotide/chemistry , Molybdenum/chemistry , Biosensing Techniques/methods , Cobalt/chemistry , Disulfides/chemistry , Oxides/chemistry , Electrodes , DNA/chemistry , Metal Nanoparticles/chemistry
3.
Brief Bioinform ; 25(3)2024 Mar 27.
Article in English | MEDLINE | ID: mdl-38706323

ABSTRACT

In recent years, cyclic peptides have emerged as a promising therapeutic modality due to their diverse biological activities. Understanding the structures of these cyclic peptides and their complexes is crucial for unlocking invaluable insights about protein target-cyclic peptide interaction, which can facilitate the development of novel-related drugs. However, conducting experimental observations is time-consuming and expensive. Computer-aided drug design methods are not practical enough in real-world applications. To tackles this challenge, we introduce HighFold, an AlphaFold-derived model in this study. By integrating specific details about the head-to-tail circle and disulfide bridge structures, the HighFold model can accurately predict the structures of cyclic peptides and their complexes. Our model demonstrates superior predictive performance compared to other existing approaches, representing a significant advancement in structure-activity research. The HighFold model is openly accessible at https://github.com/hongliangduan/HighFold.


Subject(s)
Disulfides , Peptides, Cyclic , Peptides, Cyclic/chemistry , Disulfides/chemistry , Software , Models, Molecular , Protein Conformation , Algorithms , Computational Biology/methods
4.
Anal Chem ; 96(21): 8243-8248, 2024 May 28.
Article in English | MEDLINE | ID: mdl-38733603

ABSTRACT

Native mass spectrometry (MS) continues to enjoy growing popularity as a means of providing a wealth of information on noncovalent biopolymer assemblies ranging from composition and binding stoichiometry to characterization of the topology of these assemblies. The latter frequently relies on supplementing MS measurements with limited fragmentation of the noncovalent complexes in the gas phase to identify the pairs of neighboring subunits. While this approach has met with much success in the past two decades, its implementation remains difficult (and the success record relatively modest) within one class of noncovalent assemblies: protein complexes in which at least one binding partner has multiple subunits cross-linked by disulfide bonds. We approach this problem by inducing chemical reduction of disulfide bonds under nondenaturing conditions in solution followed by native MS analysis with online buffer exchange to remove unconsumed reagents that are incompatible with the electrospray ionization process. While this approach works well with systems comprised of thiol-linked subunits that remain stable upon reduction of the disulfide bridges (such as immunoglobulins), chemical reduction frequently gives rise to species that are unstable (prone to aggregation). This problem is circumvented by taking advantage of the recently introduced cross-path reactive chromatography platform (XPRC), which allows the disulfide reduction to be carried out in-line, thereby minimizing the loss of metastable protein subunits and their noncovalent complexes with the binding partners prior to MS analysis. The feasibility of this approach is demonstrated using hemoglobin complexes with haptoglobin 1-1, a glycoprotein consisting of four polypeptide chains cross-linked by disulfide bonds.


Subject(s)
Disulfides , Oxidation-Reduction , Disulfides/chemistry , Mass Spectrometry , Protein Subunits/chemistry , Multiprotein Complexes/chemistry , Multiprotein Complexes/metabolism
5.
Langmuir ; 40(21): 11098-11105, 2024 May 28.
Article in English | MEDLINE | ID: mdl-38739904

ABSTRACT

Disulfide bonding has attracted intense interest in the tumor intracellular microenvironment-activated drug delivery systems (DDSs) in the last decades. Although various molecular structures of redox-responsive disulfide-containing DDSs have been developed, no investigation was reported on the effect of aggregation structures. Here, the effect of aggregation structures on pH/GSH dual-triggered drug release was investigated with the simplest pH/GSH dual-triggered doxorubicin-based drug self-delivery system (DSDS), the disulfide/α-amide-bridged doxorubicin dimeric prodrug (DDOX), as a model. By fast precipitation or slow self-assembly, DDOX nanoparticles were obtained. With similar diameters, they exhibited different pH/GSH dual-triggered drug releases, demonstrating the effect of aggregation structures. The π-π stacking in different degrees was revealed by the UV-vis, fluorescence, and BET analysis of the DDOX nanoparticles. The effect of the π-π stacking between the dimeric prodrug and its activated products on drug release was also explored with the molecular simulation approach. The finding opens new ideas in the design of high-performance DDSs for future precise tumor treatment.


Subject(s)
Disulfides , Doxorubicin , Drug Liberation , Glutathione , Prodrugs , Prodrugs/chemistry , Prodrugs/pharmacology , Doxorubicin/chemistry , Doxorubicin/pharmacology , Hydrogen-Ion Concentration , Disulfides/chemistry , Glutathione/chemistry , Amides/chemistry , Nanoparticles/chemistry , Dimerization , Drug Carriers/chemistry
6.
Anal Methods ; 16(20): 3278-3286, 2024 May 23.
Article in English | MEDLINE | ID: mdl-38738557

ABSTRACT

Dextromethorphan (DXM) is a widely utilized central antitussive agent, which is frequently abused by individuals seeking its recreational effect. But DXM overdose can cause some adverse effects, including brain damage, loss of consciousness, and cardiac arrhythmias, and hence its detection is significant. Herein, an electrochemical sensor based on a Cu-coordinated molecularly imprinted polymer (Cu-MIP) was fabricated for its detection. For constructing the sensor, nitrogen-doped carbon nanosheets (CCNs) were prepared through calcining chitin under an argon atmosphere, and molybdenum disulfide (MoS2) was allowed to grow on their surface. Subsequently, the obtained MoS2/CCNs composite was employed to modify a glassy carbon electrode (GCE), and the Cu-MIP was electrodeposited on the electrode in a Cu-1,10-phenanthroline (Cu-Phen) solution containing DXM, where Cu2+ played a role in facilitating electron transfer and binding DXM. Due to the large specific surface area, good electrocatalytic properties and recognition of the resulting composite, the resulting Cu-MIP/MoS2/CCNs/GCE showed high selectivity and sensitivity. Under optimized experimental conditions, the peak current of DXM and its concentration exhibited a good linear relationship over the concentration range of 0.1-100 µM, and the limit of detection (S/N = 3) was 0.02 µM. Furthermore, the electrochemical sensor presented good stability, and it was successfully used for the determination of DXM in pharmaceutical, human serum and urine samples.


Subject(s)
Carbon , Copper , Dextromethorphan , Disulfides , Electrochemical Techniques , Molecularly Imprinted Polymers , Molybdenum , Molybdenum/chemistry , Disulfides/chemistry , Dextromethorphan/analysis , Dextromethorphan/chemistry , Dextromethorphan/urine , Copper/chemistry , Electrochemical Techniques/methods , Carbon/chemistry , Molecularly Imprinted Polymers/chemistry , Chitin/chemistry , Humans , Limit of Detection , Electrodes , Antitussive Agents/chemistry , Antitussive Agents/analysis , Antitussive Agents/urine
7.
J Phys Chem B ; 128(19): 4590-4601, 2024 May 16.
Article in English | MEDLINE | ID: mdl-38701111

ABSTRACT

Cofilin, a key actin-binding protein, orchestrates the dynamics of the actomyosin network through its actin-severing activity and by promoting the recycling of actin monomers. Recent experiments suggest that cofilin forms functionally distinct oligomers via thiol post-translational modifications (PTMs) that promote actin nucleation and assembly. Despite these advances, the structural conformations of cofilin oligomers that modulate actin activity remain elusive because there are combinatorial ways to oxidize thiols in cysteines to form disulfide bonds rapidly. This study employs molecular dynamics simulations to investigate human cofilin 1 as a case study for exploring cofilin dimers via disulfide bond formation. Utilizing a biasing scheme in simulations, we focus on analyzing dimer conformations conducive to disulfide bond formation. Additionally, we explore potential PTMs arising from the examined conformational ensemble. Using the free energy profiling, our simulations unveil a range of probable cofilin dimer structures not represented in current Protein Data Bank entries. These candidate dimers are characterized by their distinct population distributions and relative free energies. Of particular note is a dimer featuring an interface between cysteines 139 and 147 residues, which demonstrates stable free energy characteristics and intriguingly symmetrical geometry. In contrast, the experimentally proposed dimer structure exhibits a less stable free energy profile. We also evaluate frustration quantification based on the energy landscape theory in the protein-protein interactions at the dimer interfaces. Notably, the 39-39 dimer configuration emerges as a promising candidate for forming cofilin tetramers, as substantiated by frustration analysis. Additionally, docking simulations with actin filaments further evaluate the stability of these cofilin dimer-actin complexes. Our findings thus offer a computational framework for understanding the role of thiol PTM of cofilin proteins in regulating oligomerization, and the subsequent cofilin-mediated actin dynamics in the actomyosin network.


Subject(s)
Actin Cytoskeleton , Disulfides , Molecular Dynamics Simulation , Disulfides/chemistry , Humans , Actin Cytoskeleton/chemistry , Actin Cytoskeleton/metabolism , Cofilin 1/chemistry , Cofilin 1/metabolism , Protein Multimerization , Actins/chemistry , Actins/metabolism , Actin Depolymerizing Factors/chemistry , Actin Depolymerizing Factors/metabolism , Thermodynamics
8.
Bioresour Technol ; 401: 130761, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38692370

ABSTRACT

Cr (VI) is a common heavy metal pollutant in electroplating wastewater. This study introduces the liquid-phase product from the hydrothermal reaction of coffee grounds (CGHCL) into the synthesis process of molybdenum disulfide, assisting in the fabrication of an intercalated, expanded core-shell structured molybdenum disulfide adsorbent (C-MoS2), designed for the adsorption and reduction of Cr (VI) from electroplating wastewater. The addition of CGHCL significantly enhances the adsorption performance of MoS2. Furthermore, C-MoS2 exhibits exceedingly high removal efficiency and excellent regenerative capability for Cr (VI)-containing electroplating wastewater. The core-shell structure effectively minimizes molybdenum leaching to the greatest extent, while the oleophobic interface is unaffected by oily substances in water, and the expanded interlayer structure ensures the long-term stability of C-MoS2 in air (90 days). This study provides a viable pathway for the resource utilization of biomass and the application of molybdenum disulfide-based materials in wastewater treatment.


Subject(s)
Biomass , Chromium , Disulfides , Molybdenum , Wastewater , Water Purification , Molybdenum/chemistry , Disulfides/chemistry , Adsorption , Wastewater/chemistry , Water Purification/methods , Chromium/chemistry , Electroplating , Water Pollutants, Chemical , Solutions
9.
ACS Appl Bio Mater ; 7(5): 3337-3345, 2024 May 20.
Article in English | MEDLINE | ID: mdl-38700956

ABSTRACT

A stimuli-responsive drug delivery nanocarrier with a core-shell structure combining photothermal therapy and chemotherapy for killing cancer cells was constructed in this study. The multifunctional nanocarrier ReS2@mSiO2-RhB entails an ReS2 hierarchical nanosphere coated with a fluorescent mesoporous silica shell. The three-dimensional hierarchical ReS2 nanostructure is capable of effectively absorbing near-infrared (NIR) light and converting it into heat. These ReS2 nanospheres were generated by a hydrothermal synthesis process leading to the self-assembly of few-layered ReS2 nanosheets. The mesoporous silica shell was further coated on the surface of the ReS2 nanospheres through a surfactant-templating sol-gel approach to provide accessible mesopores for drug uploading. A fluorescent dye (Rhodamine B) was covalently attached to silica precursors and incorporated during synthesis in the mesoporous silica walls toward conferring imaging capability to the nanocarrier. Doxorubicin (DOX), a known cancer drug, was used in a proof-of-concept study to assess the material's ability to function as a drug delivery carrier. While the silica pores are not capped, the drug molecule loading and release take advantage of the pH-governed electrostatic interactions between the drug and silica wall. The ReS2@mSiO2-RhB enabled a drug loading content as high as 19.83 mg/g doxorubicin. The ReS2@mSiO2-RhB-DOX nanocarrier's cumulative drug release rate at pH values that simulate physiological conditions showed significant pH responsiveness, reaching 59.8% at pH 6.8 and 98.5% and pH 5.5. The in vitro testing using HeLa cervical cancer cells proved that ReS2@mSiO2-RhB-DOX has a strong cancer eradication ability upon irradiation with an NIR laser owing to the combined drug delivery and photothermal effect. The results highlight the potential of ReS2@mSiO2-RhB nanoparticles for combined cancer therapy in the future.


Subject(s)
Doxorubicin , Drug Liberation , Drug Screening Assays, Antitumor , Materials Testing , Nanoparticles , Particle Size , Photothermal Therapy , Rhenium , Silicon Dioxide , Silicon Dioxide/chemistry , Humans , Doxorubicin/pharmacology , Doxorubicin/chemistry , Hydrogen-Ion Concentration , Nanoparticles/chemistry , Rhenium/chemistry , Rhenium/pharmacology , Disulfides/chemistry , Porosity , Biocompatible Materials/chemistry , Biocompatible Materials/pharmacology , Biocompatible Materials/chemical synthesis , Cell Survival/drug effects , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Drug Carriers/chemistry , HeLa Cells
10.
Virology ; 595: 110091, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38718446

ABSTRACT

Preliminary investigations have demonstrated that the cysteines located at the C-terminus of HEV ORF2 protein exhibits disulfide bonding capability during virus-like particles (VLPs) assembly. However, the effect and mechanism underlying the pairing of disulfide bonds formed by C627, C630, and C638 remains unclear. The p222 protein encompasses C-terminus and serves as a representative of HEV ORF2 to investigate the specific impacts of C627, C630, and C638. The three cysteines were subjected to site-directed mutagenesis and expressed in prokaryotes; Both the mutated proteins and p222 underwent polymerization except for p222A; Surprisingly, only p222 was observed as abundant spherical particles under transmission electron microscope (TEM); Stability and immunogenicity of the p222 exhibited higher than other mutated proteins; LC/MS/MS analysis identified four disulfide bonds in the p222. The novel findings suggest that the three cysteines contribute to structural and functional properties of ORF2 protein, highlighting the indispensability of each cysteine.


Subject(s)
Cysteine , Hepatitis E virus , Viral Proteins , Cysteine/chemistry , Cysteine/metabolism , Hepatitis E virus/genetics , Hepatitis E virus/chemistry , Viral Proteins/genetics , Viral Proteins/chemistry , Viral Proteins/metabolism , Mutagenesis, Site-Directed , Disulfides/chemistry , Disulfides/metabolism , Animals , Humans
11.
J Mater Chem B ; 12(21): 5024-5038, 2024 May 29.
Article in English | MEDLINE | ID: mdl-38712810

ABSTRACT

Composite materials can take advantages of the functional benefits of multiple pure nanomaterials to a greater degree than single nanomaterials alone. The UCNPs-MoS2 composite is a nano-application platform that combines upconversion luminescence and photothermal properties. Upconversion nanoparticles (UCNPs) are inorganic nanomaterials with long-wavelength excitation and short-wavelength tunable emission capabilities, and are able to effectively convert near-infrared (NIR) light into visible light for increased photostability. However, UCNPs have a low capacity for absorbing visible light, whereas MoS2 shows better absorption in the ultraviolet and visible regions. By integrating the benefits of UCNPs and MoS2, UCNPs-MoS2 nanocomposites can convert NIR light with a higher depth of detection into visible light for application with MoS2 through fluorescence resonance energy transfer (FRET), which compensates for the issues of MoS2's low tissue penetration light-absorbing wavelengths and expands its potential biological applications. Therefore, starting from the construction of UCNPs-MoS2 nanoplatforms, herein, we review the research progress in biological applications, including biosensing, phototherapy, bioimaging, and targeted drug delivery. Additionally, the current challenges and future development trends of UCNPs-MoS2 nanocomposites for biological applications are also discussed.


Subject(s)
Disulfides , Molybdenum , Nanocomposites , Molybdenum/chemistry , Disulfides/chemistry , Nanocomposites/chemistry , Humans , Biosensing Techniques , Animals , Phototherapy/methods , Drug Delivery Systems
12.
Biomed Mater ; 19(4)2024 May 30.
Article in English | MEDLINE | ID: mdl-38772383

ABSTRACT

The traditional chemotherapeutic agents' disadvantages such as high toxicity, untargeting and poor water solubility lead to disappointing chemotherapy effects, which restricts its clinical application. In this work, novel size-appropriate and glutathione (GSH)-responsive nano-hydrogels were successfully prepared via the active ester method between chitosan (containing -NH2) and cross-linker (containing NHS). Especially, the cross-linker was elaborately designed to possess a disulfide linkage (SS) as well as two terminal NHS groups, namely NHS-SS-NHS. These functionalities endowed chitosan-based cross-linked scaffolds with capabilities for drug loading and delivery, as well as a GSH-responsive mechanism for drug release. The prepared nano-hydrogels demonstrated excellent performance applicable morphology, excellent drug loading efficiency (∼22.5%), suitable size (∼100 nm) and long-term stability. The prepared nano-hydrogels released over 80% doxorubicin (DOX) after incubation in 10 mM GSH while a minimal DOX release less than 25% was tested in normal physiological buffer (pH = 7.4). The unloaded nano-hydrogels did not show any apparent cytotoxicity to A 549 cells. In contrast, DOX-loaded nano-hydrogels exhibited marked anti-tumor activity against A 549 cells, especially in high GSH environment. Finally, through fluorescent imaging and flow cytometry analysis, fluorescein isothiocyanate-labeled nano-hydrogels show obvious specific binding to the GSH high-expressing A549 cells and nonspecific binding to the GSH low-expressing A549 cells. Therefore, with this cross-linking approach, our present finding suggests that cross-linked chitosan nano-hydrogel drug carrier improves the anti-tumor effect of the A 549 cells and may serve as a potential injectable delivery carrier.


Subject(s)
Antineoplastic Agents , Chitosan , Cross-Linking Reagents , Doxorubicin , Glutathione , Hydrogels , Chitosan/chemistry , Humans , Doxorubicin/pharmacology , Doxorubicin/chemistry , Glutathione/chemistry , Glutathione/metabolism , Hydrogels/chemistry , Cross-Linking Reagents/chemistry , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Cell Survival/drug effects , Drug Liberation , Cell Line, Tumor , A549 Cells , Drug Carriers/chemistry , Drug Delivery Systems , Disulfides/chemistry , Delayed-Action Preparations/chemistry
13.
Talanta ; 275: 126156, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-38692048

ABSTRACT

The development of simple methods for the isolation and quantification of exosomes in biological samples is important. By using the typical two-dimensional (2D) nanomaterials, graphene oxide (GO), the present work first studied the interaction of liposomes with the nanocomposites formed by adsorbing HRP on the GO surface and found the presence of liposomes led to the release of HRP from the GO surface to the solution phase triggering the luminol-H2O2 chemiluminescence (CL) reaction to emit light. Benefiting from the similarity of exosomes to liposomes in both composition and morphology aspects, the GO-HRP nanocomposites with a mass ratio of 120:1 and 160:1 were employed for the quantitative detection of exosomes in 100-fold diluted serum samples. The whole detection process took about 15 min and as low as 3.2 × 102 particles µL-1 of exosomes could be sensitively detected. In addition to GO-HRP nanocomposites, the CL responses of other nanocomposites obtained from adsorbing HRP on other 2D nanomaterials such as layered MoS2 for exosomes were also tested. MoS2-HRP exhibited similar behavior and the LODs for the detection of exosomes were 5.8 × 102 particles µL-1. The proposed assays were a biomarker-independent quantitative method that achieved the quantification of exosomes in serum samples directly without an isolation process.


Subject(s)
Exosomes , Graphite , Horseradish Peroxidase , Luminescent Measurements , Nanostructures , Exosomes/chemistry , Graphite/chemistry , Horseradish Peroxidase/chemistry , Luminescent Measurements/methods , Adsorption , Humans , Nanostructures/chemistry , Luminol/chemistry , Molybdenum/chemistry , Disulfides/chemistry , Hydrogen Peroxide/chemistry , Limit of Detection , Liposomes/chemistry , Nanocomposites/chemistry
14.
Nat Commun ; 15(1): 3827, 2024 May 07.
Article in English | MEDLINE | ID: mdl-38714735

ABSTRACT

The main protease (Mpro) of SARS-CoV-2 is critical for viral function and a key drug target. Mpro is only active when reduced; turnover ceases upon oxidation but is restored by re-reduction. This suggests the system has evolved to survive periods in an oxidative environment, but the mechanism of this protection has not been confirmed. Here, we report a crystal structure of oxidized Mpro showing a disulfide bond between the active site cysteine, C145, and a distal cysteine, C117. Previous work proposed this disulfide provides the mechanism of protection from irreversible oxidation. Mpro forms an obligate homodimer, and the C117-C145 structure shows disruption of interactions bridging the dimer interface, implying a correlation between oxidation and dimerization. We confirm dimer stability is weakened in solution upon oxidation. Finally, we observe the protein's crystallization behavior is linked to its redox state. Oxidized Mpro spontaneously forms a distinct, more loosely packed lattice. Seeding with crystals of this lattice yields a structure with an oxidation pattern incorporating one cysteine-lysine-cysteine (SONOS) and two lysine-cysteine (NOS) bridges. These structures further our understanding of the oxidative regulation of Mpro and the crystallization conditions necessary to study this structurally.


Subject(s)
Catalytic Domain , Coronavirus 3C Proteases , Cysteine , Disulfides , Oxidation-Reduction , SARS-CoV-2 , Disulfides/chemistry , Disulfides/metabolism , SARS-CoV-2/metabolism , SARS-CoV-2/chemistry , Coronavirus 3C Proteases/metabolism , Coronavirus 3C Proteases/chemistry , Cysteine/chemistry , Cysteine/metabolism , Crystallography, X-Ray , Humans , Models, Molecular , Protein Multimerization , COVID-19/virology
15.
J Proteomics ; 301: 105194, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38723850

ABSTRACT

This study explores the disulfide bridges present in the human milk proteome by a novel approach permitting both positional identification and relative quantification of the disulfide bridges. Human milk from six donors was subjected to trypsin digestion without reduction. The digested human milk proteins were analyzed by nanoLC-timsTOF Pro combined with data analysis using xiSEARCH. A total of 85 unique disulfide bridges were identified in 25 different human milk proteins. The total relative abundance of disulfide bridge-containing peptides constituted approximately 5% of the total amount of tryptic-peptides. Seven inter-molecular disulfide bridges were identified between either α-lactalbumin and lactotransferrin (5) or αS1-casein and κ-casein (2). All cysteines involved in the observed disulfide bridges of α-lactalbumin and lactotransferrin were mapped onto protein models using AlphaFold2 Multimer to estimate the length of the observed disulfide bridges. The lengths of the disulfide bridges of lactotransferrin indicate a potential for multi- or poly-merization of lactotransferrin. The high number of intramolecular lactotransferrin disulfide bridges identified, suggests that these are more heterogeneous than previously presumed. SIGNIFICANCE: Disulfide-bridges in the human milk proteome are an often overseen post-transaltional modification. Thus, mapping the disulfide-bridges, their positions and relative abundance, are valuable new knowledge needed for an improved understanding of human milk protein behaviour. Although glycosylation and phosphorylation have been described, even less information is available on the disulfide bridges and the disulfide-bridge derived protein complexes. This is important for future work in precision fermentation for recombinant production of human milk proteins, as this will highlight which disulfide-bridges are naturally occouring in human milk proteins. Further, this knowledge would be of value for the infant formula industry as it provides more information on how to humanize bovine-milk based infant formula. The novel method developed here can be broadly applied in other biological systems as the disulfid-brigdes are important for the structure and functionality of proteins.


Subject(s)
Disulfides , Milk, Human , Proteome , Proteomics , Humans , Milk, Human/chemistry , Disulfides/chemistry , Disulfides/analysis , Proteomics/methods , Proteome/analysis , Lactoferrin/analysis , Lactoferrin/chemistry , Milk Proteins/analysis , Milk Proteins/chemistry , Lactalbumin/chemistry , Lactalbumin/analysis , Female
16.
J Chromatogr A ; 1722: 464828, 2024 May 10.
Article in English | MEDLINE | ID: mdl-38581973

ABSTRACT

The linkages of disulfide bond (DSB) play important roles in protein stability and activity. Mass spectrometry-based (MS-based) techniques become accepted tools for DSB analysis in the recent decade. In the bottom-up approach, after enzyme digestion, the neighbouring amino acids of cysteines have great impacts on the physicochemical properties of resulting disulfide bond peptides, determining their retention behaviour on liquid chromatography (LC) and their MS ionization efficiency. In this study, the addition of supercharging reagent in LC mobile phase was used to examine the impact of supercharging reagent on the charge states of disulfide-bond peptides. The results showed that 0.1 % m-nitrobenzyl alcohol (m-NBA) in LC mobile phase increased the sensitivity and charge states of DSB peptides from our model protein, equine Interleukin-5 (eIL5), as well as the resolution of reversed-phase chromatography. Notably, also the sensitivity of C-terminal peptide with His-tag significantly improved. Our findings highlight the effectiveness of employing m-NBA as a supercharging reagent when investigating disulfide-linked peptides and the C-terminal peptide with a His-tag through nano-liquid chromatography mass spectrometry.


Subject(s)
Benzyl Alcohols , Disulfides , Peptides , Disulfides/chemistry , Benzyl Alcohols/chemistry , Benzyl Alcohols/isolation & purification , Peptides/chemistry , Peptides/isolation & purification , Animals , Horses , Histidine/chemistry , Chromatography, Liquid/methods , Chromatography, Reverse-Phase/methods , Chromatography, High Pressure Liquid/methods
18.
J Environ Manage ; 358: 120827, 2024 May.
Article in English | MEDLINE | ID: mdl-38608575

ABSTRACT

The environmental safety of nanoscale molybdenum disulfide (MoS2) has attracted considerable attention, but its influence on the horizontal migration of antibiotic resistance genes and the ecological risks entailed have not been reported. This study addressed the influence of exposure to MoS2 at different concentrations up to 100 mg/L on the conjugative transfer of antibiotic resistance genes carried by RP4 plasmids with two strains of Escherichia coli. As a result, MoS2 facilitated RP4 plasmid-mediated conjugative transfer in a dose-dependent manner. The conjugation of RP4 plasmids was enhanced as much as 7-fold. The promoting effect is mainly attributable to increased membrane permeability, oxidative stress induced by reactive oxygen species, changes in extracellular polymer secretion and differential expression of the genes involved in horizontal gene transfer. The data highlight the distinct dose dependence of the conjugative transfer of antibiotic resistance genes and the need to improve awareness of the ecological and health risks of nanoscale transition metal dichalcogenides.


Subject(s)
Disulfides , Drug Resistance, Microbial , Escherichia coli , Molybdenum , Plasmids , Molybdenum/chemistry , Plasmids/genetics , Disulfides/chemistry , Escherichia coli/genetics , Escherichia coli/drug effects , Drug Resistance, Microbial/genetics , Conjugation, Genetic , Anti-Bacterial Agents/pharmacology , Gene Transfer, Horizontal
19.
Colloids Surf B Biointerfaces ; 238: 113885, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38574405

ABSTRACT

We demonstrate light-triggered dynamic covalent assembly of a linear short tetrapeptide containing two terminal cysteine residues in an AND logic manner. A photobase generator is introduced to accomplish light-mediated pH regulation to increase the reduction potential of thiols in the tetrapeptide, which activates its oxidative polymerization through disulfide bonds. Interestingly, it is elucidated that under light irradiation, mere co-existence of photobase generator and the oxidizing agent permits the polymerization performance of this tetrapeptide. Hence, a light-triggered AND logic dynamic covalent assembly of a tetrapeptide is achieved. Further, upon redox response, the reversible aggregation and disaggregation can be transformed for numerous times due to the dynamic covalent feature of disulfide bond. As a comparison, no assembly occurs for a short peptide containing one terminal cysteine residue under the same stimuli condition. This work offers a new approach to remotely control programmable molecular assembly of short linear peptides based on dynamic covalent bond, holding great potential in wide bioapplications.


Subject(s)
Light , Hydrogen-Ion Concentration , Oligopeptides/chemistry , Oxidation-Reduction , Polymerization , Cysteine/chemistry , Disulfides/chemistry , Sulfhydryl Compounds/chemistry , Logic
20.
Chemosphere ; 357: 142033, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38615961

ABSTRACT

The design and preparation of dual-functional photocatalysts for simultaneously realizing photocatalytic wastewater purification and hydrogen energy generation pose significant challenges. This article presents the engineering of a binary heterostructured photocatalyst by combining TiO2 (nanorods) and MoS2 nanosphere using a straightforward solvothermal method and the assessment of the phase structures, morphologies, and optical properties of the resulting nanocomposites using diverse analytical techniques. The TiO2(Rod)/MoS2 composite exhibits remarkable efficacy in degrading ciprofloxacin, achieving 93% removal rate within 1 h, which is four times higher than that of bare TiO2. Moreover, the optimized TiO2(Rod)/MoS2 presents an outstanding hydrogen production rate of 7415 µmol g-1, which is ∼24 times higher than that of pristine TiO2. Under UV-visible light irradiation, the TiO2(Rod)/MoS2 heterojunction displays an exceptional photocatalytic performance in terms of both photodegradation and hydrogen production, surpassing the performance of TiO2 particle/MoS2. The study findings demonstrate that TiO2(Rod)/MoS2 nanocomposites exhibit considerably improved photocatalytic degradation and hydrogen generation activities. Based on the experimental results, a possible mechanism is proposed for the transfer and separation of charge carriers in Z-scheme heterojunctions.


Subject(s)
Anti-Bacterial Agents , Disulfides , Hydrogen , Molybdenum , Nanospheres , Nanotubes , Titanium , Titanium/chemistry , Molybdenum/chemistry , Catalysis , Anti-Bacterial Agents/chemistry , Nanospheres/chemistry , Hydrogen/chemistry , Disulfides/chemistry , Nanotubes/chemistry , Nanocomposites/chemistry , Photolysis , Water Pollutants, Chemical/chemistry , Wastewater/chemistry , Ciprofloxacin/chemistry
SELECTION OF CITATIONS
SEARCH DETAIL
...