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AIMS AND OBJECTIVES: To investigate the feasibility of using peripheral perfusion index (PPI) to monitor acute limb ischaemia (ALI) in newborns after catheterisations. BACKGROUND: ALI is common complication of neonatal peripheral artery cannulation. It is important to address as soon as the early signs of ALI. PPI could aid in noninvasive evaluation of distal extremity perfusion in an effort to notify risk of potential ischaemic injury from catheterisations. DESIGN: A nested case-control study. METHODS: Clinical information of newborns who had been admitted to the Neonatal Intensive Care Unit of Jiangxi Provincial Children's Hospital and had received peripheral artery cannulation from January 2018 to January 2020 was prospectively collected. Transcutaneous blood oxygen saturation (TcSO2 ), PPI and delta-PPI (ΔPPI1; the difference in PPI values of the two arms. ΔPPI2; difference in the PPI values before and after cannulation) were recorded. We used STROBE checklist as an EQUATOR in this study. RESULTS: A total of 25 newborns with ALI were included in the study. These were then paired with 100 newborns without ALI. The PPI and TcSO2 of the cannulated limb were significantly lower in the ALI group than in the non-ALI (NALI) group (p < .05). The area under the receiver-operating characteristic curve was significant for ΔPPI1. The ΔPPI1 had a sensitivity and specificity of 92% and 87%, respectively, for diagnosing ALI. ΔPPI1 greater than 0.315 suggested that the infant was at risk of ALI. CONCLUSIONS: Monitoring the change in the PPI in newborns after catheterisations helped in the early assessment of ALI. RELEVANCE TO CLINICAL PRACTICE: Drops in the PPI and TcSO2 of the cannulated limbs might, to some extent, reflect the possibility of ALI in newborns. ΔPPI1 (the difference in PPI values of the two arms) proved to be a simple, objective parameter to predict the presence of ALI.
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Cateterismo Periférico , Enfermedades Vasculares Periféricas , Arterias , Estudios de Casos y Controles , Cateterismo Periférico/efectos adversos , Niño , Humanos , Recién Nacido , Isquemia/etiología , Índice de Perfusión , Enfermedades Vasculares Periféricas/complicacionesRESUMEN
BACKGROUND: Ferulic acid (FA), a phenolic acid widely occurring in nature, has attracted extensive attention because of its biological activity. Ovalbumin (OVA) is a commonly used carrier protein. The mechanism of FA binding with OVA was investigated by utilizing a variety of spectral analyses, accompanied by computer simulation. RESULTS: It was discovered that the fluorescence quenching mechanism of OVA by FA was a static mode as a result of the formation of an FA-OVA complex, which was verified by the concentration distributions and pure spectrum of the constituents decomposed from the high overlap spectrum signals using multivariate curve resolution-alternate least squares algorithm. Hydrogen bonds and Van der Waals forces drove the formation of FA-OVA complex with a binding constant of 1.69 × 104 L mol-1 . The presence of FA induced the loose structure of OVA with an attenuation of α-helix content and improved the thermal stability of OVA. Computer docking indicated that FA interacted with the amino acid residues Arg84, Asn88, Leu101 and Ser103 of OVA through hydrogen bonds. Molecular dynamics simulation proved that the combination of FA with OVA boosted the conformational stability of OVA and hydrogen bonds brought a crucial part in stabilizing the structure of the complex. CONCLUSIONS: The study may supply the theoretical basis for the design of FA transport system using OVA as carrier protein to improve the instability and low bioavailability of FA. © 2021 Society of Chemical Industry.
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Proteínas Portadoras , Simulación de Dinámica Molecular , Sitios de Unión , Proteínas Portadoras/metabolismo , Simulación por Computador , Ácidos Cumáricos , Simulación del Acoplamiento Molecular , Ovalbúmina/química , Unión Proteica , Espectrometría de Fluorescencia , Análisis Espectral , TermodinámicaRESUMEN
Porous organosilica monoliths have attracted much attention from both the academic and industrial fields due to their porous structure; excellent mechanical property and easily functionalized surface. A new mercapto-functionalized silicone monolith from a precursor mixture containing methyltrimethoxysilane; 3-mercaptopropyltrimethoxysilane; and 3-mercaptopropyl(dimethoxy)methylsilane prepared via a two-step acid/base hydrolysis-polycondensation process was reported. Silane precursor ratios and surfactant type were varied to control the networks of porous monolithic gels. Gold nanoparticles were loaded onto the surface of the porous organosilica monolith (POM). Versatile characterization techniques were utilized to investigate the properties of the synthesized materials with and without gold nanoparticles. Scanning electron microscopy was used to investigate the morphology of the as-synthesized porous monolith materials. Fourier transform infrared spectroscopy was applied to confirm the surface chemistry. 29Si nuclear magnetic resonance was used to investigate the hydrolysis and polycondensation of organosilane precursors. Transmission electron microscopy was carried out to prove the existence of well-dispersed gold nanoparticles on the porous materials. Ultraviolet-visible spectroscopy was utilized to evaluate the high catalytic performance of the as-synthesized Au/POM particles.
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Oro/química , Nanopartículas del Metal/química , Silanos/química , Dióxido de Silicio/química , Nanopartículas del Metal/ultraestructura , Microscopía Electrónica de Rastreo , Compuestos de Organosilicio , PorosidadRESUMEN
BACKGROUND: Quinoline yellow (QY), a synthetic colourant widely used in the food industry, has caused extensive concerns because of its potentially harmful effects on human health. In the present work, the interactions between QY and human serum albumin (HSA) were characterized by multiple spectroscopic methods, a chemometric algorithm, and molecular modelling studies. RESULTS: The concentration profiles and pure spectra obtained for the components (QY, HSA and QY-HSA complex) from analyses of the expanded UV-visible absorption data matrices by multivariate curve resolution alternating least squares confirmed the QY-HSA interaction process. QY quenched the fluorescence of HSA through formation of a QY-HSA complex that was stabilized by moderate affinity. Hydrophobic forces and hydrogen bonding play major roles in the binding of QY to HSA. Site-specific marker-induced displacement results suggest that QY binds to subdomain IIA of HSA. This was corroborated by the molecular docking results. Decreases in HSA surface hydrophobicity and free sulfhydryl group content indicate that QY causes a contraction of the peptide strand in HSA, hiding the hydrophobic patches of the protein. Analyses by UV-visible absorption, circular dichroism, and three-dimensional fluorescence spectroscopy found that QY causes microenvironmental perturbations around the fluorophores and secondary structure changes in HSA. CONCLUSION: This work shows that QY binds to HSA, affecting its structural and functional properties, and provides new insights into the binding mechanism and a comprehensive understanding of the toxicity of QY to biological processes. © 2018 Society of Chemical Industry.
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Quinolinas/química , Albúmina Sérica/química , Dicroismo Circular , Humanos , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Simulación del Acoplamiento Molecular , Unión Proteica , EspectrofotometríaRESUMEN
BACKGROUND: The suppression of α-glucosidase activity to retard glucose absorption is an important therapy for type-2 diabetes. Corosolic acid (CRA) is a potential antidiabetic component in many plant-based foods and herbs. In this study, the interplay mechanism between α-glucosidase and corosolic acid was investigated by several methods, including three-dimensional fluorescence spectra, circular dichroism spectra, and molecular simulation. RESULTS: Corosolic acid significantly inhibited α-glucosidase reversibly in an uncompetitive manner and its IC50 value was 1.35 × 10-5 mol L-1 . A combination of CRA with myricetin exerted a weak synergy against α-glucosidase. The intrinsic fluorescence of α-glucosidase was quenched via a static quenching course and the binding constant was 3.47 × 103 L mol-1 at 298 K. The binding of CRA to α-glucosidase was mainly driven by hydrophobic forces and resulted in a partial extension of the protein polypeptide chain with a loss of α-helix content. The molecular simulation illustrated that CRA bound to the entrance part of the active center of α-glucosidase and interacted with the amino acid residues Ser157, Arg442, Phe303, Arg315, Tyr158, and Gln353, which could hinder the release of substrate and catalytic reaction product, eventually suppressing the catalytic activity of α-glucosidase. CONCLUSIONS: These results may suggest new insights into corosolic acid from food sources as a potential α-glucosidase inhibitor that could better control diabetes. © 2019 Society of Chemical Industry.
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Inhibidores Enzimáticos/química , Triterpenos/química , alfa-Glucosidasas/química , Secuencias de Aminoácidos , Sitios de Unión , Dicroismo Circular , Humanos , Hipoglucemiantes/química , Simulación del Acoplamiento MolecularRESUMEN
The electrochemical reduction of CO2 is an efficient channel to facilitate energy conversion, but the rapid design and rational screening of high-performance catalysts remain a great challenge. In this work, we investigated the relationships between the configuration, energy, and electronic properties of SnS2 loaded with transition metal single atom (TM@SnS2) and analyzed the mechanism of CO2 activation and reduction by using density functional theory. The "charge transfer bridge" promoted the adsorption of CO2 on TM@SnS2, thus enhancing the binding of HCOOH∗ to the catalyst for further hydrogenation and reduction to high-value CH4. The research revealed that the binding free energy of COOH∗ on TM@SnS2 formed a "volcano curve" with the limiting potential of CO2 reduction to CH4, and the TM@SnS2 (TM = Cr, Ru, Os, and Pt) at the "volcano top" exhibited a high CH4 activity.
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Indole-3-propionic acid (IPA) is a plant growth regulator with good specificity and long action. IPA may be harmful to human health because of its accumulation in vegetables and fruits. Therefore, in this study, the properties of the interaction between calf thymus DNA (ctDNA) and IPA were systematically explored using multispectroscopic and computational modeling approaches. Analysis of fluorescence spectra showed that IPA binding to ctDNA to spontaneously form a complex was mainly driven by hydrogen bonds and hydrophobic interaction. DNA melting analysis, viscosity analysis, DNA cleavage study, and circular dichroism measurement revealed the groove binding of IPA to ctDNA and showed that the binding did not significantly change ctDNA confirmation. Furthermore, molecular docking found that IPA attached in the A-T rich minor groove region of the DNA. Molecular dynamics simulation showed that DNA and IPA formed a stable complex and IPA caused slight fluctuations for the residues at the binding site. Gel electrophoresis experiments showed that IPA did not significantly disrupt the DNA structure. These findings may provide useful information on the potential toxicological effects and environmental risk assessments of IPA residue in food at the molecular level.
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Japanese Encephalitis Virus (JEV), the predominant cause of viral encephalitis in many Asian countries, affects approximately 68,000 people annually. Lysosomes are dynamic structures that regulate cellular metabolism by mediating lysosomal biogenesis and autophagy. Here, we showed that lysosome-associated membrane protein 1 (LAMP1) and LAMP2 were downregulated in cells after JEV infection, resulting in a decrease in the quantity of acidified lysosomes and impaired lysosomal catabolism. What's more, JEV nonstructural protein 4B plays key roles in the reduction of LAMP1/2 via the autophagy-lysosome pathway. JEV NS4B also promoted abnormal aggregation of SLA-DR, an important component of the swine MHC-II molecule family involved in antigen presentation and CD4+ cell activation initiation. Mechanistically, NS4B localized to the ER during JEV infection and interacted with GRP78, leading to the activation of ER stress-mediated autophagy. The 131-204 amino acid (aa) region of NS4B is essential for autophagy induction and LAMP1/2 reduction. In summary, our findings reveal a novel pathway by which JEV induces autophagy and disrupts lysosomal function.
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Autofagia , Regulación hacia Abajo , Virus de la Encefalitis Japonesa (Especie) , Proteína 2 de la Membrana Asociada a los Lisosomas , Lisosomas , Lisosomas/metabolismo , Animales , Virus de la Encefalitis Japonesa (Especie)/fisiología , Proteína 2 de la Membrana Asociada a los Lisosomas/genética , Proteína 2 de la Membrana Asociada a los Lisosomas/metabolismo , Porcinos , Proteína 1 de la Membrana Asociada a los Lisosomas/metabolismo , Proteína 1 de la Membrana Asociada a los Lisosomas/genética , Encefalitis Japonesa/virología , Encefalitis Japonesa/veterinaria , Línea Celular , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismo , Proteínas de Membrana de los Lisosomas/metabolismo , Proteínas de Membrana de los Lisosomas/genéticaRESUMEN
Japanese encephalitis virus (JEV), a mosquito-borne zoonotic virus, is one of the most important causes of human viral encephalitis. JEV relies on various attachment or entry co-factors to enter host cells. Among these co-factors, hTIM-1 has been identified as an attachment factor to promote JEV infection through interacting with phosphatidylserine (PS) on the viral envelope. However, the reasons why JEV prefers to use hTIM-1 over other PS binding receptors are unknown. Here, we demonstrated that hTIM-1 can directly interact with JEV E protein. The interaction between hTIM-1 and JEV relies on specific binding sites, respectively, ND114115 in the hTIM-1 IgV domain and K38 of the E protein. Furthermore, during the early stage of infection, hTIM-1 and JEV are co-internalized into cells and transported into early and late endosomes. Additionally, we found that the hTIM-1 soluble ectodomain protein effectively inhibits JEV infection in vitro. Moreover, hTIM-1-specific antibodies have been shown to downregulate JEV infectivity in cells. Taken together, these findings suggested that hTIM-1 protein directly interacts with JEV E protein and mediates JEV infection, in addition to the PS-TIM-1 interaction.
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Virus de la Encefalitis Japonesa (Especie) , Encefalitis Japonesa , Animales , Humanos , Virus de la Encefalitis Japonesa (Especie)/fisiología , Proteínas del Envoltorio Viral/metabolismoRESUMEN
Alzheimer's disease (AD) is the most prevalent chronic neurodegenerative disease in elderly individuals, causing dementia. Acetylcholinesterase (AChE) is regarded as one of the most popular drug targets for AD. Herbal secondary metabolites are frequently cited as a major source of AChE inhibitors. In the current study, baicalein, a typical bioactive flavonoid, was found to inhibit AChE competitively, with an associated IC50 value of 6.42 ± 0.07 µM, through a monophasic kinetic process. The AChE fluorescence quenching by baicalein was a static process. The binding constant between baicalein and AChE was an order of magnitude of 104 L mol-1, and hydrogen bonding and hydrophobic interaction were the major forces for forming the baicalein-AChE complex. Circular dichroism analysis revealed that baicalein caused the AChE structure to shrink and increased its surface hydrophobicity by increasing the α-helix and ß-turn contents and decreasing the ß-sheet and random coil structure content. Molecular docking revealed that baicalein predominated at the active site of AChE, likely tightening the gorge entrance and preventing the substrate from entering and binding with the enzyme, resulting in AChE inhibition. The preceding findings were confirmed by molecular dynamics simulation. The current study provides an insight into the molecular-level mechanism of baicalein interaction with AChE, which may offer new ideas for the research and development of anti-AD functional foods and drugs.
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Two flavonoids with similar structures, baicalein (Bai) and chrysin (Chr), were selected to investigate the interactions with ß-lactoglobulin (BLG) and the influences on the structure and functional properties of BLG by multispectral methods combined with molecular docking and dynamic (MD) simulation techniques. The results of fluorescence quenching suggested that both Bai and Chr interacted with BLG to form complexes with the binding constant of the magnitude of 105 L·mol-1. The binding affinity between BLG and Bai was stronger than that of Chr due to more hydrogen bond formation in Bai-BLG binding. The existence of Bai or Chr induced a looser conformation of BLG, but Chr had a greater effect on the secondary structure of BLG. The surface hydrophobicity and free sulfhydryl group content of BLG lessened due to the presence of the two flavonoids. Molecular docking was performed at the binding site of Bai or Chr located in the surface of BLG, and hydrophobic interaction and hydrogen bond actuated the formation of the Bai/Chr-BLG complex. Molecular dynamics simulation verified that the combination of Chr and BLG decreased the stability of BLG, while Bai had little effect on it. Moreover, the foaming properties of BLG got better in the presence of the two flavonoids compounds and Bai improved its emulsification stability of the protein, but Chr had the opposite effect. This work provides a new idea for the development of novel dietary supplements using functional proteins as flavonoid delivery vectors.
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Japanese encephalitis virus (JEV) is a major causative agent of neurological infection affecting humans and pigs. Human T Cell Immunoglobulin and Mucin Domain 1 (hTIM-1) enhances the infection of JEV through virion-associated phosphatidylserine (PS) binding. Here, five swine TIM-1 (sTIM-1) gene variants were cloned from pig lung tissues by reverse-transcriptase polymerase chain reaction (RT-PCR). Sequence alignment analysis revealed that the gene homology between the sTIM-1 and hTIM-1 was 42.3-43.8%. Furthermore, ectopic expression of all five sTIM-1 variants in 293 T cells can promote JEV entry and infection. However, sTIM-1 V3 exhibited significantly less potent at promoting virus entry compared to the other four variants. Further studies revealed that the 34th amino acid of sTIM-1is critical for the entry of JEV, which is Pro34 in sTIM-1V3 while Leu34 in other four sTIM-1 variants. Mechanically, leucine at locus 34 was associated with the membrane distribution of sTIM-1, thereby affecting viral entry and infection. In total, our findings provide evidence that the PS receptor sTIM-1 promotes the infection of JEV and that the 34th amino acid position is critical for sTIM-1 to mediate viral infection.
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Virus de la Encefalitis Japonesa (Especie) , Encefalitis Japonesa , Porcinos , Animales , Humanos , Virus de la Encefalitis Japonesa (Especie)/genética , Fosfatidilserinas , Leucina/genética , Encefalitis Japonesa/veterinaria , Mutación , Inmunoglobulinas , Mucinas/genéticaRESUMEN
Glutenin has limited applicability in food industry due to poor water solubility and emulsifying properties. In this study, the physicochemical properties of glutenin were improved by combined treatments of alkaline pH-shifting or acidic pH with heating. The surface morphology, structure and physicochemical properties were measured during the modification process of glutenin. Results showed that the smaller square clusters and regular tubular fibrils were observed in modified glutenin and the α-helix proportion of the treated glutenin was finally increased to 59.90 ± 0.01%. Compared with untreated glutenin, the combined treatments of pH-shifting with heating as well as fibrillation process increased the solubility of glutenin by 21.3 and 3.5 times, respectively. Moreover, the treated glutenin showed excellent emulsifying stability (EAI: 50.84 ± 0.51 m2g-1) and thermal stability (peak temperature increased from 109.58 to 149.05 °C). This study provides an informative basis for improving the physicochemical and functional properties of glutenin.
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Glútenes , Triticum , Ácidos , Glútenes/química , Concentración de Iones de Hidrógeno , Solubilidad , Triticum/químicaRESUMEN
Pigs are the amplifying hosts of Japanese encephalitis virus (JEV). Currently, the safe and effective live attenuated vaccine made of JEV strain SA14-14-2, which does not express NS1', is widely used in humans and domestic animals to prevent JEV infection. In this study, we constructed the NS1' expression recombinant virus (rA66G) through a single nucleotide mutation in NS2A of JEV strain SA14-14-2. Animal experiments showed that NS1' significantly enhanced JEV infection in pig central nervous system (CNS) and tonsil tissues. Pigs shed virus in oronasal secretions in the JEV rA66G virus inoculation group, indicating that NS1' may facilitate the horizontal transmission of JEV. Additionally, dendritic cells (DCs) and macrophages are the main target cells of JEV infection in pig tonsils, which are an important site of persistent JEV infection. The reduction of major histocompatibility complex class II (MHC II) and activation of inducible nitric oxide synthase (iNOS) in pig tonsils caused by viral infection may create a beneficial environment for persistent JEV infection. These results are of significance for JEV infection in pigs and lay the foundation for future studies of JEV persistent infection in pig tonsils. IMPORTANCE Pigs are amplification hosts for Japanese encephalitis virus (JEV). JEV can persist in the tonsils for months despite the presence of neutralizing antibodies. The present study shows that NS1' increases JEV infection in pig tonsils. In addition, DCs and macrophages in the tonsils are the target cells for JEV infection, and JEV NS1' promotes virus infection in DCs and macrophages. This study reveals a novel function of JEV NS1' protein and lays the foundation for future studies of JEV persistent infection in pig tonsils.
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Virus de la Encefalitis Japonesa (Especie) , Encefalitis Japonesa , Animales , Línea Celular , Células Dendríticas , Virus de la Encefalitis Japonesa (Especie)/genética , Virus de la Encefalitis Japonesa (Especie)/metabolismo , Encefalitis Japonesa/prevención & control , Macrófagos , Tonsila Palatina , Porcinos , Vacunas AtenuadasRESUMEN
Epicatechin gallate (ECG) is one of the main components of catechins and has multiple bioactivities. In this work, the inhibitory ability and molecular mechanism of ECG on XO were investigated systematically. ECG was determined as a mixed xanthine oxidase (XO) inhibitor with an IC50 value of 19.33 ± 0.45 µM. The promotion of reduced XO and the inhibition of the formation of uric acid by ECG led to a decrease in O2- radical. The stable ECG-XO complex was formed by hydrogen bonds and van der Waals forces, with the binding constant of the magnitude of 104 L mol-1, and ECG influenced the stability of the polypeptide skeleton and resulted in a more compact conformation of XO. Computational simulations further characterized the binding characteristics and revealed that the inhibitory mechanism of ECG on XO was likely that ECG bound to the vicinity of flavin adenine dinucleotide (FAD) and altered the conformation of XO, hindering the entry of substrate and the diffusion of catalytic products. ECG and allopurinol bound to different active sites of XO and exerted a synergistic inhibitory effect through enhancing their binding stability with XO and changing the target amino acid residues of XO. These findings may provide a theoretical basis for the further application of ECG in the fields of food nutrition and functional foods.
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In this study, the antiglycation potential and mechanisms of vitexin were explored in vitro by multispectroscopy, microscope imaging, high-resolution mass spectrometry, and computational simulations. Vitexin was found to show much stronger antiglycation effects than aminoguanidine. The inhibition against the fluorescent advanced glycation end products was more than 80% at 500 µM vitexin in both bovine serum albumin (BSA)-fructose and BSA-methylglyoxal (MGO) models. Treated with 100 and 200 µM vitexin for 24 h, the contents of MGO were reduced to 4.97 and 0.2%, respectively, and only one vitexin-mono-MGO adduct was formed. LC-Orbitrap-MS/MS analysis showed that vitexin altered the glycated sites and reduced the glycation degree of some sites. The mechanisms of vitexin against protein glycation were mainly through BSA structural protection, MGO trapping, and alteration of glycation sites induced by interaction with BSA. These findings provided valuable information about the functional development of vitexin as a potential antiglycation agent.
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Piruvaldehído , Espectrometría de Masas en Tándem , Apigenina , Productos Finales de Glicación Avanzada/metabolismo , Glicosilación , Albúmina Sérica Bovina/metabolismoRESUMEN
4-Octylphenol (OP) is an environmental estrogen that can enter organisms through the food chain and cause various toxic effects. Here, the interaction between OP and human serum albumin (HSA) was explored through multipectral, molecular docking and dynamics simulation. The results showed that OP and HSA formed a ground state complex through a static quenching mechanism, and the interaction was spontaneously driven by hydrogen bonds and hydrophobic interaction forces. The binding constant at different temperatures was measured to be on the order of 105 L mol-1. Site competition experiments suggested that OP interacted with amino acid residues Lys195, Cy245 and Cys246 located at the Sudlow site I of HSA, resulting in a more stretched protein peptide. The presence of OP increased the surface hydrophobicity of HSA, and reduced the content of α-helix in HSA by 3.4%. FT-IR spectra showed that OP interacted with the C=O and C-H groups of the polypeptide backbone. Molecular docking demonstrated that OP mainly bound to Site I of HSA and hydrogen bonds participated in the interaction. In addition, molecular dynamics simulations further explored the stability and dynamic behavior of the OP-HSA complex through RMSD, RMSF, SASA and Rg.
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Simulación de Dinámica Molecular , Albúmina Sérica Humana , Sitios de Unión , Dicroismo Circular , Humanos , Simulación del Acoplamiento Molecular , Fenoles , Unión Proteica , Albúmina Sérica Humana/metabolismo , Espectrometría de Fluorescencia , Espectroscopía Infrarroja por Transformada de Fourier , TermodinámicaRESUMEN
Japanese encephalitis virus (JEV) is a flavivirus transmitted by mosquitoes that causes severe encephalitis in humans and animals. It has been suggested that AXL, a transmembrane protein, can promote the replication of various flaviviruses, such as dengue (DENV), Zika (ZIKV), and West Nile (WNV) viruses. However, the effect of AXL on JEV infection has not yet been determined. In the present study, we demonstrate that AXL is down-regulated after JEV infection in the late stage. JEV NS2B-3 protein specifically interacted with AXL, and promoted AXL degradation through the ubiquitin-proteasome pathway. AXL-degradation increased cell apoptosis by disrupting phosphatidylinositol 3-kinase (PI3K)/Akt signal transduction. In addition, the degradation of AXL promoted JEV release to supernatant, whereas the virus in the cell lysates decreased. The supplementation of AXL ligand Gas6 inhibited the JEV-mediated degradation of AXL. Altogether, we discover a new function of NS2B-3 during the process of JEV replication, and provide a new insight into the interactions between JEV and cell hosts.
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Apoptosis , Virus de la Encefalitis Japonesa (Especie) , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Tirosina Quinasas Receptoras/metabolismo , Proteínas no Estructurales Virales/metabolismo , Liberación del Virus , Animales , Células Cultivadas , Virus de la Encefalitis Japonesa (Especie)/fisiología , Encefalitis Japonesa , Humanos , Fosfatidilinositol 3-Quinasas , Virión , Tirosina Quinasa del Receptor AxlRESUMEN
The Japanese encephalitis serogroup of the neurogenic Flavivirus has a specific feature that expresses a non-structural protein NS1' produced through a programmed -1 ribosomal frameshifting (-1 PRF). Herein, C19orf66, a novel member of interferon-stimulated gene (ISG) products, exhibited significant activity of antagonizing Japanese encephalitis virus (JEV) infection. Overexpression of C19orf66 in 293T cells significantly inhibited JEV replication, while knock-down of endogenous C19orf66 in HeLa cells and A549 cells significantly increased virus replication. Notably, C19orf66 had an inhibitory effect on frameshift production of JEV NS1'. The inhibition was more significant when C19orf66 and JEV NS1-NS2A were co-expressed in the 293T cells. Both C19orf66-209 and C19orf66-Zincmut did not significantly change the NS1' to NS1 ratio and had weaker antiviral effects than C19orf66. Similarly, C19orf66-209 and C19orf66-Zincmut had no significant effect on the expression of the JEV NS3 protein, whose expression was down-regulated by C19orf66 via the lysosome-dependent pathway. These findings suggest that C19orf66 may possess at least two different mechanisms of antagonizing JEV infection. This study identified C19orf66 as a novel interferon-stimulated gene product that can inhibit JEV replication by targeting -1 PRF and the NS3 protein. The study provides baseline information for the future development of broad-spectrum antiviral agents against JEV.
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Virus de la Encefalitis Japonesa (Especie) , Encefalitis Japonesa , Proteínas de Unión al ARN , Proteínas no Estructurales Virales , Replicación Viral , Células A549 , Virus de la Encefalitis Japonesa (Especie)/genética , Virus de la Encefalitis Japonesa (Especie)/fisiología , Células HeLa , Humanos , ARN Helicasas , Serina Endopeptidasas , Proteínas no Estructurales Virales/genéticaRESUMEN
Inhibition of tyrosinase activity contributes to the control of food browning and skin pigmentation diseases. Herein, the inhibitory mechanism of epigallocatechin-3-gallate (EGCG) and gallocatechin gallate (GCG) on tyrosinase were investigated. Both EGCG and GCG inhibited tyrosinase in a mixed manner with the IC50 values of 39.4 ± 0.54 µM and 36.8 ± 0.21 µM, and showed a synergism with their combination, while EGCG and GCG combined with kojic acid (IC50 = 19.2 ± 0.26 µM) exhibited antagonism and additive effect, respectively. EGCG and GCG interacted with tyrosinase mainly by hydrogen bonding and hydrophobic interactions and induced a looser conformation of tyrosinase. Molecular docking indicated that EGCG and GCG bound to the active center of tyrosinase and interacted with copper ions and key amino acid residues. Molecular dynamics simulation further characterized the structure and property of EGCG/GCG-tyrosinase complex. This study provides novel insights into the mechanism of catechins as tyrosinase inhibitors.