Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 87
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Proc Natl Acad Sci U S A ; 120(22): e2219569120, 2023 05 30.
Artículo en Inglés | MEDLINE | ID: mdl-37216523

RESUMEN

FFAR1 is a G-protein-coupled receptor (GPCR) that responds to circulating free fatty acids to enhance glucose-stimulated insulin secretion and release of incretin hormones. Due to the glucose-lowering effect of FFAR1 activation, potent agonists for this receptor have been developed for the treatment of diabetes. Previous structural and biochemical studies of FFAR1 showed multiple sites of ligand binding to the inactive state but left the mechanism of fatty acid interaction and receptor activation unknown. We used cryo-electron microscopy to elucidate structures of activated FFAR1 bound to a Gq mimetic, which were induced either by the endogenous FFA ligand docosahexaenoic acid or γ-linolenic acid and the agonist drug TAK-875. Our data identify the orthosteric pocket for fatty acids and show how both endogenous hormones and synthetic agonists induce changes in helical packing along the outside of the receptor that propagate to exposure of the G-protein-coupling site. These structures show how FFAR1 functions without the highly conserved "DRY" and "NPXXY" motifs of class A GPCRs and also illustrate how the orthosteric site of a receptor can be bypassed by membrane-embedded drugs to confer full activation of G protein signaling.


Asunto(s)
Ácidos Grasos , Insulina , Insulina/metabolismo , Ligandos , Microscopía por Crioelectrón , Receptores Acoplados a Proteínas G/metabolismo , Ácidos Grasos no Esterificados , Glucosa
2.
J Asthma ; : 1-9, 2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38889078

RESUMEN

OBJECTIVE: To review the efficacy, symptoms, inflammatory factors and pulmonary function of different doses of budesonide aerosol inhalation in the treatment of patients with asthma. METHODS: The Chinese and English literature databases were searched with "Effects of different doses of budesonide aerosol inhalation on the efficacy, lung function, inflammation, symptoms and adverse reactions in patients with asthma" as the search direction, and a Meta-analysis was performed. RESULTS: Compared with the low dose group, the efficacy, PEF and FEV1 were significantly increased and the clinical symptom score, TNF-α and IL-4 were significantly decreased in the high dose group (p < 0.05). There was no significant difference in IFN-γ level and the incidence of adverse reactions between the two groups (p > 0.05). CONCLUSION: High-dose budesonide aerosol inhalation therapy can improve the efficacy and lung function of patients, reduce inflammation and clinical symptoms, and does not increase the risk of adverse reactions, which is worthy of clinical promotion.

3.
Alzheimers Dement ; 19(11): 5074-5085, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37186161

RESUMEN

INTRODUCTION: The prevalence and risk factors for subjective cognitive decline (SCD) and its correlation with objective cognition decline (OCD) among community-dwelling older adults is inconsistent. METHODS: Older adults underwent neuropsychological and clinical evaluations to reach a consensus on diagnoses. RESULTS: This study included 7486 adults without mild cognitive impairment and dementia (mean age: 71.35 years [standard deviation = 5.40]). The sex-, age-, and residence-adjusted SCD prevalence was 58.33% overall (95% confidence interval: 58.29% to 58.37%), with higher rates of 61.25% and 59.87% in rural and female subgroups, respectively. SCD global and OCD language, SCD memory and OCD global, SCD and OCD memory, and SCD and OCD language were negatively correlated in fully adjusted models. Seven health and lifestyle factors were associated with an increased risk for SCD. DISCUSSION: SCD affected 58.33% of older adults and may indicate concurrent OCD, which should prompt the initiation of preventative intervention for dementia. HIGHLIGHTS: SCD affects 58.33% of older adults in China. SCD may indicate concurrent objective cognitive decline. Difficulty finding words and memory impairments may indicate a risk for AD. The presence of SCD may prompt preventative treatment initiation of MCI or dementia. Social network factors may be initial targets for the early prevention of SCD.


Asunto(s)
Disfunción Cognitiva , Demencia , Humanos , Femenino , Anciano , Estudios de Cohortes , Prevalencia , Vida Independiente , Disfunción Cognitiva/psicología , Cognición , Envejecimiento , Factores de Riesgo , Demencia/etiología , Pruebas Neuropsicológicas
4.
Pharmacogenet Genomics ; 32(2): 43-50, 2022 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-34369425

RESUMEN

OBJECTIVE: Genetic alterations in CDKN2A tumor suppressor gene on chromosome 9p21 confer a predisposition to childhood acute lymphoblastic leukemia (ALL). Genome-wide association studies have identified missense variants in CDKN2A associated with the development of ALL. This study systematically evaluated the effects of CDKN2A coding variants on ALL risk. METHODS: We genotyped the CDKN2A coding region in 308 childhood ALL cases enrolled in CCCG-ALL-2015 clinical trials by Sanger Sequencing. Cell growth assay, cell cycle assay, MTT-based cell toxicity assay, and western blot were performed to assess the CDKN2A coding variants on ALL predisposition. RESULTS: We identified 10 novel exonic germline variants, including 6 missense mutations (p.A21V, p.G45A and p.V115L of p16INK4A; p.T31R, p.R90G, and p.R129L of p14ARF) and 1 nonsense mutation and 1 heterozygous termination codon mutation in exon 2 (p16INK4A p.S129X). Functional studies indicate that five novel variants resulted in reduced tumor suppressor activity of p16INK4A, and increased the susceptibility to the leukemic transformation of hematopoietic progenitor cells. Compared to other variants, p.H142R contributes higher sensitivity to CDK4/6 inhibitors. CONCLUSION: These findings provide direct insight into the influence of inherited genetic variants at the CDKN2A coding region on the development of ALL and the precise clinical application of CDK4/6 inhibitors.


Asunto(s)
Estudio de Asociación del Genoma Completo , Leucemia-Linfoma Linfoblástico de Células Precursoras , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Humanos , Mutación , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteína p14ARF Supresora de Tumor/genética
5.
Angew Chem Int Ed Engl ; 61(33): e202207088, 2022 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-35751877

RESUMEN

Bioinspired palladium-catalyzed intramolecular cyclization of amino acid derivatives containing a vinyl iodide moiety by C-H activation enabled rapid access to a wide range of functionalized proline derivatives with an exocyclic olefin. To demonstrate the practicality of this methodology, the functionalized prolines were used as intermediates for the synthesis of several natural products: lucentamycin A, oxotomaymycin, oxoprothracarcin, and barmumycin.


Asunto(s)
Productos Biológicos , Paladio , Catálisis , Ciclización , Estructura Molecular , Paladio/química , Prolina
6.
Langmuir ; 37(40): 11835-11843, 2021 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-34586807

RESUMEN

A surfactant interfacial adsorption process is highly associated with its micellization behaviors in the water phase, which is of great fundamental and practical significance in enhanced oil recovery. In this paper, the typical anionic surfactant 1-dodecanesulfonic acid sodium (DAS) and nonionic surfactants octylphenol polyoxyethylene ether-n (OP-n, n = 1, 5, and 10) are introduced to investigate their micellization behavior and interfacial adsorption process via molecular dynamics simulation. Number density profiles reveal that the additional OP5 molecules in the water phase generate the mixed micelle with DAS molecules and greatly promote its interfacial adsorption. Interaction energy calculation is employed to confirm the interaction of anionic/nonionic surfactants in the mixed micelle. Then, the radial distribution function, solvent-accessible surface area, and solvation free energy are calculated to further explore and verify the adsorption mechanism of the mixed micelle. It is found that the nonionic surfactant obviously decreases the hydrophilicity of the mixed micelle in the water phase, which should be responsible for its intensive tendency of the interfacial adsorption.

7.
J Phys Chem A ; 125(24): 5397-5405, 2021 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-34114820

RESUMEN

Mercury (Hg) pollution is a global environmental problem. The abiotic formation of dimethylmercury (DMeHg) from monomethylmercury (MMeHg) may account for a large portion of DMeHg in oceans. Previous experimental work has shown that abiotic formation of DMeHg from MMeHg can be facilitated by reduced sulfur groups on sulfide mineral surfaces. In that work, a mechanism was proposed in which neighboring MMeHg moieties bound to sulfide sites on a mineral surface react through an SN2-type mechanism to form DMeHg and incorporate the remaining Hg atoms into the mineral surface. Here, we perform density functional theory calculations to explore the mechanisms of DMeHg formation on the 110 surface of a CdS(s) (hawleyite) nanoparticle. We show that coordination of MMeHg substituents to adjacent reduced sulfur groups protruding from the surface indeed facilitates DMeHg formation and that the reaction proceeds through direct transmethylation from one MMeHg substituent to another. Coordination of Hg by multiple S atoms provides a transition-state stabilization and activates a C-Hg bond for methyl transfer. In addition, solvation effects play an important role in the surface reconstruction of the nanoparticle and in decreasing the energetic barrier for DMeHg formation relative to the corresponding reaction in vacuo.

8.
Ecotoxicol Environ Saf ; 222: 112497, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34273850

RESUMEN

Sewage sludge (SS) and garden waste (GW) compost can be used as soil amendments to improve the soil environment. Studies done till date have been focused on the changes of harmful substances during sludge composting, but the safety and efficacy of SS and GW composting on woodland soil environment are still unclear. In the study, a field experiment was performed using to investigate the safety and efficacy of SS and GW compost as a soil amendment on woodland soil. Soil nutrients (such as nitrogen, phosphorus and potassium), organic matter and electrical conductivity were significantly increased after the addition of the SS and GW compost, while there were no significant changes in soil heavy metals content and soil enzyme activities. From these soil properties, it was found that SS and GW compost was safe and efficacious in improving the soil environment. The application of SS and GW compost had no significant effect on microbial diversity. Co-occurrence network analysis revealed that SS and GW compost efficaciously enhanced the interaction between bacterial communities, which proved that it was safe and efficacious. Furthermore, SS and GW compost enhanced ABC transporters and carbohydrate metabolism of bacterial community, while reduced the pathotroph action (such as the plant pathogen) and wood saprotrophs. Overall, these results proved the safety and efficacy of SS and GW compost as soil amendments after being added to the soil. This study contributes to the use of harmless treatments and reutilization processes of SS and GW.


Asunto(s)
Compostaje , Contaminantes del Suelo , Bosques , Jardines , Aguas del Alcantarillado , Suelo , Contaminantes del Suelo/análisis
9.
J Comput Chem ; 41(6): 528-537, 2020 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-31721253

RESUMEN

The mer operon in bacteria encodes a set of proteins and enzymes that impart resistance to environmental mercury toxicity by importing Hg2+ and reducing it to volatile Hg(0). Because the reduction occurs in the cytoplasm, mercuric ions must first be transported across the cytoplasmic membrane by one of a few known transporters. MerF is the smallest of these, containing only two transmembrane helices and two pairs of vicinal cysteines that coordinate mercuric ions. In this work, we use molecular dynamics simulations to characterize the dynamics of MerF in its apo and Hg2+ -bound states. We find that the apo state positions one of the cysteine pairs closer to the periplasmic side of the membrane, while in the bound state the same pair approaches the cytoplasmic side. This finding is consistent with the functional requirement of accepting Hg2+ from the periplasmic space, sequestering it on acceptance, and transferring it to the cytoplasm. Conformational changes in the TM helices facilitate the functional interaction of the two cysteine pairs. Free-energy calculations provide a barrier of 16 kcal/mol for the association of the periplasmic Hg2+ -bound protein MerP with MerF and 7 kcal/mol for the subsequent association of MerF's two cysteine pairs. Despite the significant conformational changes required to move the binding site across the membrane, coarse-grained simulations of multiple copies of MerF support the expectation that it functions as a monomer. Our results demonstrate how conformational changes and binding thermodynamics could lead to such a small membrane protein acting as an ion transporter. Published 2019. This article is a U.S. Government work and is in the public domain in the USA.


Asunto(s)
Proteínas Bacterianas/química , Escherichia coli/química , Mercurio/química , Simulación de Dinámica Molecular , Termodinámica , Proteínas Bacterianas/metabolismo , Transporte Biológico , Escherichia coli/metabolismo , Mercurio/metabolismo
10.
J Comput Chem ; 41(2): 147-155, 2020 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-31603259

RESUMEN

To assess the chemical reactivity, toxicity, and mobility of pollutants in the environment, knowledge of their species distributions is critical. Because their direct measurement is often infeasible, speciation modeling is widely adopted. Mercury (Hg) is a representative pollutant for which study of its speciation benefits from modeling. However, Hg speciation modeling is often hindered by a lack of reliable thermodynamic constants. Although computational chemistry (e.g., density functional theory [DFT]) can generate these constants, methods for directly coupling DFT and speciation modeling are not available. Here, we combine computational chemistry and continuum-scale modeling with curated online databases to ameliorate the problem of unreliable inputs to Hg speciation modeling. Our AQUA-MER databases and web server (https://aquamer.ornl.gov) provides direct speciation results by combining web-based interfaces to a speciation calculator, databases of thermodynamic constants, and a computational chemistry toolkit to estimate missing constants. Although Hg is presented as a concrete use case, AQUA-MER can also be readily applied to other elements. © 2019 Wiley Periodicals, Inc.

11.
Langmuir ; 36(7): 1839-1847, 2020 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-32009407

RESUMEN

The interfacial assembly process and configuration of the pseudogemini surfactant fabricated by sodium dodecyl benzene sulfonate (SDBS) and 4,4'-oxydianilinium chloride (ODC) were studied using quantum mechanical calculations and molecular dynamics (MD) simulations. The MD simulation results revealed that SDBS and ODC showed the vertical and horizontal arrangements at the oil/water interface, respectively, and the interfacial assembled configuration presented an unexpected "H" shape rather than the traditional "U" shape. The radial distribution functions between the head groups and water molecules were employed to explore the effects of the surrounding water molecules on the SDBS/ODC interaction. Furthermore, the results of the nonbonded interaction calculations and the reduced density gradient method directly confirmed that the cation-π interaction should be responsible for the SDBS/ODC assembly mechanism and the final configuration at the oil/water interface.

12.
Soft Matter ; 15(27): 5529-5536, 2019 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-31241648

RESUMEN

Additional HCl can facilely control the dynamic noncovalent interaction between anionic surfactant sodium dodecyl benzene sulfonate (SDBS) and additional organic matter, 4,4'-oxydianiline (ODA), at the water/oil interface. At low HCl concentration (ODA/HCl molar ratio (r) = 1 : 1.5, [ODA] = 250 mg L-1), the ODA+ ions effectively enhanced the SDBS ability to reduce the water/oil interfacial tension (IFT) by about two orders of magnitude, while the (SDBS)2/ODA2+ gemini-like surfactants could be constructed at a relatively high HCl concentration (r = 1 : 4, [ODA] = 250 mg L-1), which could largely reduce the IFT to 1.19 × 10-3 mN m-1. Molecular simulation was employed to explore the interfacial activity of ODAn+ (ODA+/ODA2+) ions and the SDBS/ODAn+ interaction. The control experiments used another three surfactants to verify the proposed model. The pH-switchable gradual protonation of amino groups in ODA molecules determined the SDBS/ODA interfacial assembly, which was responsible for the reversal of IFT variations and the related emulsion behaviors.

13.
Inorg Chem ; 57(8): 4590-4601, 2018 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-29600856

RESUMEN

The mononuclear [Cl-FeIII(dpa)-Cl]+ (1Cl) complex containing a square planar tetradentate polypyridine ligand has been reported to catalyze water oxidation in pH = 1 aqueous medium with ceric ammonium nitrate (CAN) as a chemical oxidant. The reaction mechanism of the oxygen evolution driven by this catalyst was investigated by means of density functional calculations. The results showed that one chloride ligand of 1Cl has to exchange with a water molecule to generate 1, [Cl-FeIII(dpa)-OH2]2+, as the starting species of the catalytic cycle. The initial one-electron oxidation of 1 is coupled with the release of two protons, generating [Cl-FeIV(dpa)═O]+ (2). Another one-electron transfer from 2 leads to the formation of an FeV═O complex [Cl-FeV(dpa)═O]2+ (3), which triggers the critical O-O bond formation. The electronic structure of 3 was found to be very similar to that of the high-valent heme-iron center of P450 enzymes, termed Compound I, in which a π-cation radical ligand is believed to support a formal iron(IV)-oxo core. More importantly, 3 and Compound I share the same tendency toward electrophilic reactions. Two competing pathways were suggested for the O-O bond formation based on the present calculations. One is the nitrate nucleophilic attack on the iron(V)-oxo moiety with a total barrier of 12.3 kcal mol-1. In this case, nitrate functions as a co-catalyst for the dioxygen formation. The other is the water nucleophilic attack on iron(V)-oxo with a greater barrier of 16.5 kcal mol-1. In addition, ligand degradation via methyl hydrogen abstraction was found to have a barrier similar to that of the O-O bond formation, while the aromatic carbon hydroxylation has a higher barrier.

14.
Int J Colorectal Dis ; 33(9): 1241-1249, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29931408

RESUMEN

PURPOSE: We investigated the prognostic value of distant metastasis sites among patients with metastatic colorectal cancer (CRC) and the significance of metastasectomy and resection of the primary CRC. METHODS: Between 2010 and 2014, patients diagnosed with metastatic colorectal adenocarcinoma were selected using the surveillance, epidemiology, and end results (SEER) database. The prognosis of these patients was compared according to the site of metastasis (liver, lung, bone, and brain). A total of 15,133 patients suffered from isolated organ involvement, while 5135 patients experienced multiple organ metastases. RESULTS: In the isolated organ metastasis cohort, median overall survival (OS) for patients with liver, lung, bone, and brain metastases was 16, 20, 7, and 5 months, respectively. Patients with isolated lung metastases had better cancer-specific survival (CSS) and OS as compared to patients with metastases at any other sites (p < 0.0001 for both CSS and OS). Patients with isolated liver metastases had better prognosis as compared to patients with isolated bone or brain metastases (p < 0.0001 for both CSS and OS). Moreover, patients with a single metastatic site had better prognosis than patients with multiple organs involved (p < 0.0001 for both CSS and OS). Multivariate analysis in patients with isolated organ metastases demonstrated that age ≤ 60 years, rectal cancer, being married, non-black race, N0 stage, and surgery of the primary and distant lesions showed more favorable prognosis. CONCLUSIONS: The metastatic site was an independent prognostic factor in stage IV colorectal cancer. Also, carefully chosen patients may benefit from surgery.


Asunto(s)
Adenocarcinoma/secundario , Adenocarcinoma/cirugía , Colectomía , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/cirugía , Metastasectomía , Adenocarcinoma/mortalidad , Toma de Decisiones Clínicas , Colectomía/efectos adversos , Colectomía/mortalidad , Neoplasias Colorrectales/mortalidad , Supervivencia sin Enfermedad , Femenino , Humanos , Masculino , Metastasectomía/efectos adversos , Metastasectomía/mortalidad , Persona de Mediana Edad , Estadificación de Neoplasias , Selección de Paciente , Estudios Retrospectivos , Medición de Riesgo , Factores de Riesgo , Programa de VERF , Factores de Tiempo , Estados Unidos/epidemiología
15.
J Phys Chem A ; 122(17): 4366-4374, 2018 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-29633840

RESUMEN

Developing accurate quantum chemical approaches for calculating p Kas is of broad interest. Useful accuracy can be obtained by using density functional theory (DFT) in combination with a polarizable continuum solvent model. However, some classes of molecules present problems for this approach, yielding errors greater than 5 p K units. Various methods have been developed to improve the accuracy of the combined strategy. These methods perform well but either do not generalize or introduce additional degrees of freedom, increasing the computational cost. The Solvation Model based on Density (SMD) has emerged as one of the most commonly used continuum solvent models. Nevertheless, for some classes of organic compounds, e.g., thiols, the p Kas calculated with the original SMD model show errors of 6-10 p K units, and we traced these errors to inaccuracies in the solvation free energies of the anions. To improve the accuracy of p Kas calculated with DFT and the SMD model, we developed a scaled solvent-accessible surface approach for constructing the solute-solvent boundary. By using a "direct" approach, in which all quantities are computed in the presence of the continuum solvent, the use of thermodynamic cycles is avoided. Furthermore, no explicit water molecules are required. Three benchmark data sets of experimentally measured p Ka values, including 28 carboxylic acids, 10 aliphatic amines, and 45 thiols, were used to assess the optimized SMD model, which we call SMD with a scaled solvent-accessible surface (SMDsSAS). Of the methods tested, the M06-2X density functional approximation, 6-31+G(d,p) basis set, and SMDsSAS solvent model provided the most accurate p Kas for each set, yielding mean unsigned errors of 0.9, 0.4, and 0.5 p K units, respectively, for carboxylic acids, aliphatic amines, and thiols. This approach is therefore useful for efficiently calculating the p Kas of environmentally relevant functional groups.

16.
Cancer Cell Int ; 15: 120, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26689843

RESUMEN

BACKGROUND: DIXDC1 (Dishevelled-Axin domain containing 1) is a positive regulator of the Wnt pathway. In the field of cancer research, the role of DIXDC1 is unclear. Our previous in vitro study showed that DIXDC1 enhances ß-catenin nuclear accumulation in gastric cancer cell lines. The aim of this study was to detect the expression of DIXDC1 in different histological subtypes of gastric carcinoma and to evaluate the correlation between the expression of DIXDC1 and ß-catenin localization and clinicopathological parameters, including patients' survival. METHODS: Immunohistochemical staining was performed to characterize the expression of DIXDC1 and ß-catenin in archived materials from 259 cases of gastric carcinoma. The χ2 test and the Fisher's test were used to analyze correlations between DIXDC1 expression, ß-catenin localization, and clinicopathological parameters. Univariate analyses were performed using the Kaplan-Meier method, and the survival difference between groups was assessed by the log-rank test. Multivariate analysis was performed using the Cox proportional hazards regression model. RESULTS: Positive DIXDC1 staining was detected in tumor cells in 123 of 259 (47.5 %) cases. DIXDC1 expression in gastric carcinoma was significantly correlated with the histological intestinal-type (P < 0.001), the depth of tumor invasion (P < 0.001) and the lymph node metastasis (P = 0.006). In the intestinal-type, DIXDC1 was correlated with the nuclear and cytoplasmic ß-catenin expression (P = 0.002). Kaplan-Meier analysis indicated that patients with high DIXDC1 expression had poor disease-specific survival (P < 0.001), especially in the intestinal-type. Moreover, multivariate regression analysis showed that positive expression of DIXDC1 was an independent prognostic predictor of intestinal-type gastric carcinoma. CONCLUSION: Our study indicated that DIXDC1 is a significant independent prognostic indicator in intestinal-type gastric carcinoma that plays an important role in carcinogenesis and progression of gastric carcinoma through the Wnt signaling pathway.

17.
J Chem Inf Model ; 55(8): 1616-27, 2015 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-26131601

RESUMEN

Discovery of high-affinity and high-selectivity agonists of 5-HT1AR has become very attractive due to their potential therapeutic effects on multiple 5-HT1AR-related psychological and neurological problems. On the basis of our previously designed lead compound FW01 (Ki = 51.9 nM, denoted as 9a in the present study), we performed large-scale molecular dynamics simulations and molecular docking operations on 5-HT1AR-9a binding. We found the flip-packing events for the headgroup of 9a, and we also found that its tail group could bind flexibly at the agonist-binding site of 5-HT1AR. By finely tuning the flip-packing phenomenon of the 9a headgroup and tuning the binding flexibility of 9a tail group, we virtually designed a series of new 9a derivatives through molecular docking operations and first-principles calculations and predicted that these newly designed 9a derivatives should be higher-affinity agonists of 5-HT1AR. The computational predictions on the new 9a derivatives have been confirmed by our wet-experimental studies as chemical synthesis, binding affinity assays, and agonistic-function assays. The consistency between our computational design and wet-experimental measurements has led to our discovery of higher-affinity agonists of 5-HT1AR, with ∼50-fold increase in receptor-binding affinity and ∼25-fold improvements in agonistic function. In addition, our newly designed 5-HT1AR agonists showed very high selectivity of 5-HT1AR over subtype 5-HT2AR and also over three subtypes of dopamine receptors (D1, D2, and D3).


Asunto(s)
Diseño de Fármacos , Receptor de Serotonina 5-HT1A/metabolismo , Agonistas del Receptor de Serotonina 5-HT1/química , Agonistas del Receptor de Serotonina 5-HT1/farmacología , Sitios de Unión , Humanos , Modelos Moleculares , Receptor de Serotonina 5-HT1A/química , Receptor de Serotonina 5-HT2A/química , Receptor de Serotonina 5-HT2A/metabolismo , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/metabolismo
18.
Adv Exp Med Biol ; 827: 311-24, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25387972

RESUMEN

The multiscale model strategy, hybrid quantum mechanics and molecular mechanics (QM/MM), has become more and more prevalent in the theoretical study of enzymatic reactions. It combines both the efficiency of the Newtonian molecular calculations and the accuracy of the quantum mechanical methods. Simulation using QM/MM multiscale model may be one of the most promising approaches that could further narrow the gap between the theoretical models and the real problems. It is capable of dealing with not only the conformational changes of biomacromolecules, but also the catalytic reactions. Herein, we reviewed some of our recent work to demonstrate the application of the QM/MM simulations in exploring the enzymatic reactions.


Asunto(s)
Citocromos c/metabolismo , Teoría Cuántica , Citocromos c/química , Protones
19.
Biochemistry ; 53(46): 7211-22, 2014 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-25343681

RESUMEN

Mercuric reductase, MerA, is a key enzyme in bacterial mercury resistance. This homodimeric enzyme captures and reduces toxic Hg2+ to Hg0, which is relatively unreactive and can exit the cell passively. Prior to reduction, the Hg2+ is transferred from a pair of cysteines (C558' and C559' using Tn501 numbering) at the C-terminus of one monomer to another pair of cysteines (C136 and C141) in the catalytic site of the other monomer. Here, we present the X-ray structure of the C-terminal Hg2+ complex of the C136A/C141A double mutant of the Tn501 MerA catalytic core and explore the molecular mechanism of this Hg transfer with quantum mechanical/molecular mechanical (QM/MM) calculations. The transfer is found to be nearly thermoneutral and to pass through a stable tricoordinated intermediate that is marginally less stable than the two end states. For the overall process, Hg2+ is always paired with at least two thiolates and thus is present at both the C-terminal and catalytic binding sites as a neutral complex. Prior to Hg2+ transfer, C141 is negatively charged. As Hg2+ is transferred into the catalytic site, a proton is transferred from C136 to C559' while C558' becomes negatively charged, resulting in the net transfer of a negative charge over a distance of ∼7.5 Å. Thus, the transport of this soft divalent cation is made energetically feasible by pairing a competition between multiple Cys thiols and/or thiolates for Hg2+ with a competition between the Hg2+ and protons for the thiolates.


Asunto(s)
Proteínas Bacterianas/química , Mercurio/metabolismo , Oxidorreductasas/química , Pseudomonas aeruginosa/química , Proteínas Bacterianas/metabolismo , Dominio Catalítico , Cristalografía por Rayos X , Cisteína/química , Cisteína/metabolismo , Modelos Moleculares , Oxidorreductasas/metabolismo , Conformación Proteica , Multimerización de Proteína , Pseudomonas aeruginosa/metabolismo
20.
Exp Anim ; 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38960678

RESUMEN

Acute lung injury (ALI) is a common complication after hemorrhagic shock (HS), which is associated with HS-induced inflammatory response, oxidative stress, and cell apoptosis. This study aimed to investigate the therapeutic efficacy of 8-Gingerol, a constituent extracted from ginger, on ALI after HS in rats. We established a fixed press hemorrhage model in SD rats, in which the HS rats were administered 15 or 30 mg/kg of 8-Gingerol by intraperitoneal injection before fluid resuscitation. H&E staining and TUNEL staining were performed to evaluate histopathological changes and cell apoptosis in lung tissues, respectively. Quantitative reverse transcription PCR and Western blot were used to measure gene and protein expression. Pro-inflammatory cytokines were detected by ELISA kits. Immunofluorescence of myeloperoxidase was used to evaluate neutrophil infiltration. 8-Gingerol reduced pulmonary edema, alveolar wall thickness, and cell apoptosis in lung tissues of HS rats. Regarding inflammatory responses, 8-Gingerol attenuated neutrophil infiltration in lung tissues, reduced pro-inflammatory cytokines in lung tissues and bronchoalveolar lavage fluid, and decreased the levels of NLRP3, ASC, and cleaved caspase 1 in lung tissues. Additionally, 8-Gingerol ameliorated oxidative stress in lung tissues as evidenced by increased antioxidant indicators (SOD and GSH) and decreased production of MDA and ROS. The therapeutic effects of 8-Gingerol were associated with the regulation of MAPK and Nrf2/HO-1 pathways. These results support 8-Gingerol as a promising drug for the treatment of HS-induced ALI.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA