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1.
Food Chem ; 454: 139788, 2024 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-38810459

RESUMEN

Licochalcone A (LCA) is extracted from licorice plants and used as a food additive. Citric acid (CA) and alanine (Ala) are food additives with good regulatory functions. This study aims to investigate the formation and in vitro release mechanism of the LCA eutectogel using supramolecular self-assembly technology. The mechanism of self-assembly indicates that the resulting eutectogel has strong intermolecular interactions. The formation mechanism of LCA eutectogel suggests that LCA is dispersed in nano form in the DES solution before self-assembly and dispersed in molecular form in the eutectogel after self-assembly. Mesoscopic MD simulation studies indicate that the interaction energy between LCA Ala-CA(5:5) eutectogel and the solvent interface is relatively low, suggesting it may have a better drug release rate, consistent with the in vitro release results. In conclusion, the study successfully prepares LCA eutectogel and provides theoretical guidance for the development and application of novel eutectogel for food application.

2.
Adv Mater ; : e2404120, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38727702

RESUMEN

This study innovatively addresses challenges in enhancing upconversion efficiency in lanthanide-based nanoparticles (UCNPs) by exploiting Shewanella oneidensis MR-1, a microorganism capable of extracellular electron transfer. Electroactive membranes, rich in c-type cytochromes, are extracted from bacteria and integrated into membrane-integrated liposomes (MILs), encapsulating core-shelled UCNPs with an optically inactive shell, forming UCNP@MIL constructs. The electroactive membrane, tailored to donate electrons through the inert shell, independently boosts upconversion emission under near-infrared excitation (980 or 1550 nm), bypassing ligand-sensitized UCNPs. The optically inactive shell restricts energy migration, emphasizing electroactive membrane electron donation. Density functional theory calculations elucidate efficient electron transfer due to the electroactive membrane hemes' highest occupied molecular orbital being higher than the valence band maximum of the optically inactive shell, crucial for enhancing energy transfer to emitter ions. The introduction of a SiO2 insulator coating diminishes light enhancement, underscoring the importance of unimpeded electron transfer. Luminescence enhancement remains resilient to variations in emitter or sensitizing ions, highlighting the robustness of the electron transfer-induced phenomenon. However, altering the inert shell material diminishes enhancement, emphasizing the role of electron transfer. This methodology holds significant promise for diverse biological applications. UCNP@MIL offers an advantage in cellular uptake, which proves beneficial for cell imaging.

3.
J Ethnopharmacol ; 325: 117739, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38301986

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Licorice is the dry roots and rhizomes of Glycyrrhiza uralensis Fisch., Glycyrrhiza glabra L. and Glycyrrhiza inflata Bat., which was first recorded in Shengnong's herbal classic. Licorice flavonoid (LF) is the main compound isolated from licorice with an indispensable action in treating gastric ulcer (GU). However, the underlying mechanisms need to be further explored. AIM OF THE STUDY: This study aimed to investigate and further elucidate the mechanisms of LF against ethanol-induced GU using an integrated approach. MATERIALS AND METHODS: The anti-GU effects of LF were evaluated in an ethanol-induced gastric injury rat model. Then, the metabolomics approach was applied to explore the specific metabolites and metabolic pathways. Next, the network pharmacology combined with metabolomics strategy was employed to predict the targets and pathways of LF for GU. Finally, these predictions were validated by molecular docking, RT-qPCR, and western blotting. RESULTS: LF had a positive impact on gastric injury and regulated the expression of GU-related factors. Upon serum metabolomics analysis, 25 metabolic biomarkers of LF in GU treatment were identified, which were primarily involved in amino acid metabolism, carbohydrate metabolism, and other related processes. Subsequently, a "components-targets-metabolites" network was constructed, revealing six key targets (HSP90AA1, AKT1, MAPK1, EGFR, ESR1, PIK3CA) that may be associated with GU treatment. More importantly, KEGG analysis highlighted the importance of the PI3K/AKT pathway including key targets, as a critical route through which LF exerted its anti-GU effects. Molecular docking analyses confirmed that the core components of LF exhibited a strong affinity for key targets. Furthermore, RT-qPCR and western blotting results indicated that LF could reverse the expression of these targets, activate the PI3K/AKT pathway, and ultimately reduce apoptosis. CONCLUSION: LF exerted a gastroprotective effect against gastric ulcer induced by ethanol, and the therapeutic mechanism may involve improving metabolism and suppressing apoptosis through the PI3K-AKT pathway.


Asunto(s)
Glycyrrhiza , Úlcera Gástrica , Animales , Ratas , Úlcera Gástrica/inducido químicamente , Úlcera Gástrica/tratamiento farmacológico , Fosfatidilinositol 3-Quinasas , Proteínas Proto-Oncogénicas c-akt , Simulación del Acoplamiento Molecular , Apoptosis , Etanol , Flavonoides/farmacología , Flavonoides/uso terapéutico , Transducción de Señal
4.
Heliyon ; 9(12): e22421, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38076040

RESUMEN

Melasma is a pigmentation disease with refractory and high recurrence risk. Therefore, finding effective treatment has become the focus of research. This study aimed to reveal the mechanism of Licorice rose beverage (LRB) in treating melasma from the perspective of network pharmacology and in vitro and in vivo experimental techniques. Network pharmacological studies have shown that Isolicoflavonol, quercetin, and kaempferol are the main active components of anti-melasma and tyrosinase is the main target. Molecular docking studies have shown that these compounds have a good affinity for these targets. In vitro tyrosinase inhibition experiments showed that LRB could significantly inhibit tyrosinase activity. In vivo studies showed that LRB could significantly improve skin damage and skin pigmentation, reduce the activities of serum and skin tyrosinase in model mice, increase the activity of SOD in serum, and reduce the content of MDA in mice, showing a good effect of anti-melasma. In conclusion, these findings reveal the molecular mechanism of LRB in treating melasma and provide the scientific basis for this product's development and clinical application.

5.
Artículo en Inglés | MEDLINE | ID: mdl-37980702

RESUMEN

Licorice flavonoids (LFs) are derived from perennial herb licorice and have been attaining a considerable interest in cosmetic and skin ailment treatments. However, some LFs compounds exhibited poor permeation and retention capability, which restricted their application. In this paper, we systematically investigated and compared the enhancement efficacy and mechanisms of different penetration enhancers (surfactants) with distinct lipophilicity or "heat and cool" characteristics on ten LFs compounds. Herein, the aim was to unveil how seven different enhancers modified the stratum corneum (SC) surface and influence the drug-enhancers-skin interaction, and to relate these effects to permeation enhancing effects of ten LFs compounds. The enhancing efficacy was evaluated by enhancement ratio (ER)permeation, ERretention, and ERcom, which was conducted on the porcine skin. It was summarized that heat capsaicin (CaP) and lipophilic Plurol® Oleique CC 497 (POCC) caused the most significance of SC lipid fluidity, SC water loss, and surface structure alterations, thereby resulting in a higher permeation enhancing effects than other enhancers. CaP could completely occupied drug-skin interaction sites in the SC, while POCC only occupied most drug-skin interactions. Moreover, the enhancing efficacy of both POCC and CaP was dependent on the log P values of LFs. For impervious LFs with low drug solubility, enhancing their drug solubility could help them permeate into the SC. For high-permeation LFs, their permeation was inhibited ascribed to the strong drug-enhancer-skin strength in the SC. More importantly, drug-surfactant-skin energy possessed a good negative correlation with the LFs permeation amount for most LFs molecules. Additionally, the activation of transient receptor potential vanilloid 1 (TRPV1) could enhance LFs permeation by CaP. The study provided novel insights for drug permeation enhancement from the viewpoint of molecular pharmaceutics, as well as the scientific utilization of different enhancers in topical or transdermal formulations.

6.
Biomed Pharmacother ; 169: 115868, 2023 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-37952360

RESUMEN

Licorice flavonoid (LF) is the main component of Glycyrrhizae Radix et Rhizoma, a "medicine food homology" herbal medicine, which has anti-digestive ulcer activity, but the mechanism in anti-gastric ulcer (GU) remains to be elucidated. In this study, we manifested that LF increased the viability of human gastric mucosal epithelial (GES-1) cells, attenuated ethanol (EtOH)-induced manifestations, reduced histological injury, suppressed inflammation, and restored gastric mucosal barrier in GU rats. After LF therapy, the EtOH-induced gut dysbiosis was partly modulated, and short-chain fatty acids (SCFAs) like butyric acid, propionic acid, and valeric acid were found in higher concentrations. We discovered that the majority of genera that increased in the GU group had a negative correlation with SCFAs in the intestinal tract. In addition, LF-upregulated SCFAs boosted mucus secretion in the gastric epithelium and the expression of mucoprotein (MUC) 5AC and MUC6, particularly the MUC5AC in the gastric foveola. Moreover, LF triggered the EGFR/ERK signal pathway which promoted gastric mucus cell regeneration. Therefore, the findings indicated that LF could inhibit inflammation, promote mucosal barrier repair and angiogenesis, regulate gut microbiota and SCFA metabolism; more importantly, promote epithelial proliferation via activation of the EGFR/ERK pathway, exerting a protective and regenerative effect on the gastric mucosa.


Asunto(s)
Microbioma Gastrointestinal , Glycyrrhiza , Úlcera Gástrica , Ratas , Humanos , Animales , Úlcera Gástrica/inducido químicamente , Úlcera Gástrica/tratamiento farmacológico , Úlcera Gástrica/metabolismo , Ácidos Grasos Volátiles/metabolismo , Inflamación/metabolismo , Etanol/efectos adversos , Moco/metabolismo , Receptores ErbB/metabolismo
7.
Sensors (Basel) ; 23(15)2023 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-37571586

RESUMEN

Cylindrical components are parts with curved surfaces, and their high-precision defect testing is of great significance to industrial production. This paper proposes a noncontact internal defect imaging method for cylindrical components, and an automatic photoacoustic testing platform is built. A synthetic aperture focusing technology in the polar coordinate system based on laser ultrasonic (LU-pSAFT) is established, and the relationship between the imaging quality and position of discrete points is analyzed. In order to verify the validity of this method, small holes of Φ0.5 mm in the aluminum alloy rod are tested. During the imaging process, since a variety of waveforms can be excited by the pulsed laser synchronously, the masked longitudinal waves reflected by small holes need to be filtered and windowed to achieve high-quality imaging. In addition, the influence of ultrasonic beam angle and signal array spacing on imaging quality is analyzed. The results show that the method can accurately present the outline of the small hole, the circumferential resolution of the small hole is less than 1° and the dimensional accuracy and position error are less than 0.1 mm.

8.
Soft Robot ; 10(6): 1083-1098, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37140563

RESUMEN

Although various soft pneumatic actuators have been studied, their performance, including load capacity, has not been satisfied yet. Enhancing their actuation capability and using them to develop soft robots with high performance is still an open and challenging issue. In this study, we developed novel pneumatic actuators based on fiber-reinforced airbags as a solution to this problem, of which the maximum pressure reaches more than 100 kPa. Through cellular rearrangement, the developed actuators could bend uni- or bidirectionally, achieving large driving force, large deformation, and high conformability. Hence, they could be used to develop soft manipulators with relatively large payload (up to 10 kg, about 50 times the body self-weight) and soft climbing robots with high mobility. In this article, we first present the design of the airbag-based actuators and then model the airbag to obtain the relationship between the pneumatic pressure, external force, and deformation. Subsequently, we validate the models by comparing the simulated and measured results and test the load capacity of the bending actuators. Afterward, we present the development of a soft pneumatic robot that can rapidly climb horizontal, inclined, and vertical poles with different cross-sectional shapes and even outdoor natural objects, like bamboos, at a speed of 12.6 mm/s generally. In particular, it can dexterously transition between poles at any angle, which, to the best of our knowledge, has not been achieved before.

9.
Soft Robot ; 10(4): 808-824, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36897741

RESUMEN

Muscle driving is a critical actuation mode of soft or flexible robots and plays a key role in the motion of most animals. Although the system development of soft robots has been extensively investigated, the general kinematic modeling of soft bodies and the design methods used for muscle-driven soft robots (MDSRs) are inadequate. With a focus on homogeneous MDSRs, this article presents a framework for kinematic modeling and computational design. Based on continuum mechanics theory, the mechanical characteristics of soft bodies were first described using a deformation gradient tensor and energy density function. The discretized deformation was then depicted using a triangular meshing tool according to the piecewise linear hypothesis. Deformation models of MDSRs caused by external driving points or internal muscle units were established by the constitutive modeling of hyperelastic materials. The computational design of the MDSR was then addressed based on kinematic models and deformation analysis. Algorithms were proposed to infer the design parameters from the target deformation and to determine the optimal muscles. Several MDSRs were developed, and experiments were conducted to verify the effectiveness of the presented models and design algorithms. The computational and experimental results were compared and evaluated using a quantitative index. The presented framework of deformation modeling and computational design of MDSRs can facilitate the design of soft robots with complex deformations, such as humanoid faces.

10.
Artículo en Inglés | MEDLINE | ID: mdl-36913526

RESUMEN

To date, the transdermal delivery study mainly focused on the drug delivery systems' design and efficacy evaluation. Few studies reported the structure-affinity relationship of the drug with the skin, further revealing the action sites of the drugs for enhanced permeation. Flavonoids attained a considerable interest in transdermal administration. The aim is to develop a systematic approach to evaluate the substructures that were favorable for flavonoid delivery into the skin and understand how these action sites interacted with lipids and bound to multidrug resistance protein 1 (MRP1) for enhanced transdermal delivery. First, we investigated the permeation properties of various flavonoids on the porcine skin or rat skin. We found that 4'-OH (hydroxyl group on the carbon 4' position) rather than 7-OH on the flavonoids was the key group for flavonoid permeation and retention, while 4'-OCH3 and -CH2═CH2-CH-(CH3)2 were unfavorable for drug delivery. 4'-OH could decrease flavonoids' lipophilicity to an appropriate log P and polarizability for better transdermal drug delivery. In the stratum corneum, flavonoids used 4'-OH as a hand to specifically grab the C═O group of the ceramide NS (Cer), which increased the miscibility of flavonoids and Cer and then disturbed the lipid arrangement of Cer, thereby facilitating their penetration. Subsequently, we constructed overexpressed MRP1 HaCaT/MRP1 cells by permanent transfection of human MRP1 cDNA in wild HaCaT cells. In the dermis, we observed that 4'-OH, 7-OH, and 6-OCH3 substructures were involved in H-bond formation within MRP1, which increased the flavonoid affinity with MRP1 and flavonoid efflux transport. Moreover, the expression of MRP1 was significantly enhanced after the treatment of flavonoids on the rat skin. Collectively, 4'-OH served as the action site for increased lipid disruption and enhanced affinity for MRP1, which facilitate the transdermal delivery of flavonoids, providing valuable guidelines for molecular modification and drug design of flavonoids.

11.
Chaos ; 32(10): 103102, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36319306

RESUMEN

With the outbreak of COVID-19, great loss and damage were brought to human society, making the study of epidemic spreading become a significant topic nowadays. To analyze the spread of infectious diseases among different areas, e.g., communities, cities, or countries, we construct a network, based on the epidemic model and the network coupling, whose nodes denote areas, and edges represent population migrations between two areas. Each node follows its dynamic, which describes an epidemic spreading among individuals in an area, and the node also interacts with other nodes, which indicates the spreading among different areas. By giving mathematical proof, we deduce that our model has a stable solution despite the network structure. We propose the peak infected ratio (PIR) as a property of infectious diseases in a certain area, which is not independent of the network structure. We find that increasing the population mobility or the disease infectiousness both cause higher peak infected population all over different by simulation. Furthermore, we apply our model to real-world data on COVID-19 and after properly adjusting the parameters of our model, the distribution of the peak infection ratio in different areas can be well fitted.


Asunto(s)
COVID-19 , Enfermedades Transmisibles , Epidemias , Humanos , Simulación por Computador , Brotes de Enfermedades , Enfermedades Transmisibles/epidemiología
12.
Int J Pharm ; 625: 122109, 2022 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-35973589

RESUMEN

Alopecia affected approximately 16.6% of all people in China, however, treatment options remain limited due to the side effects. Plant bioactive compound baicalin (BC) possesses hair growth-promotion activity, but poor water solubility and unsuitable log P value restrict its topical application, and natural Glycyrrhizin (GL) can exactly overcome these drawbacks. Here, BC was encapsulated in GL to form GL-BC micelles for alopecia treatment. Simultaneously, tween 80 (TW) as carriers was incorporated in the GL-BC to form GL-TW-BC micelles. The topical penetration, penetration pathways, cellular uptake and the underlying mechanisms behind the hair loss reconstruction of the GL micelles were investigated. We found the optimal GL-BC and GL-TW-BC formulations significantly improved the penetration and accumulation of BC in the porcine skin predominantly through the hair follicles pathways without causing skin irritation, which resulted in a targeted treatment. The proliferation of human dermal papilla cells (hDPCs) and effective cellular uptake was also enhanced. Moreover, the activation of the Wnt/ß-catenin pathway, up-expression of vascular endothelial growth factor (VEGF), α-melanocyte-stimulating hormone (α-MSH) and interleukin-10 (IL-10) were the mechanisms of micelles for the hair recovery. Interestingly, GL and BC exhibited a synergistic treatment of alopecia. Collectively, GL-BC and GL-TW-BC can be used as promising approaches for the treatment of alopecia.


Asunto(s)
Folículo Piloso , Micelas , Alopecia/tratamiento farmacológico , Alopecia/metabolismo , Flavonoides , Ácido Glicirrínico/metabolismo , Folículo Piloso/metabolismo , Humanos , Factor A de Crecimiento Endotelial Vascular/metabolismo
13.
IEEE Trans Pattern Anal Mach Intell ; 44(6): 3110-3122, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33373296

RESUMEN

Establishing correct correspondences between two images should consider both local and global spatial context. Given putative correspondences of feature points in two views, in this paper, we propose Order-Aware Network, which infers the probabilities of correspondences being inliers and regresses the relative pose encoded by the essential or fundamental matrix. Specifically, this proposed network is built hierarchically and comprises three operations. First, to capture the local context of sparse correspondences, the network clusters unordered input correspondences by learning a soft assignment matrix. These clusters are in canonical order and invariant to input permutations. Next, the clusters are spatially correlated to encode the global context of correspondences. After that, the context-encoded clusters are interpolated back to the original size and position to build a hierarchical architecture. We intensively experiment on both outdoor and indoor datasets. The accuracy of the two-view geometry and correspondences are significantly improved over the state-of-the-arts. Besides, based on the proposed method and advanced local feature, we won the first place in CVPR 2019 image matching workshop challenge and also achieve state-of-the-art results in the Visual Localization benchmark. Code is available at https://github.com/zjhthu/OANet.

14.
Int J Mol Sci ; 22(18)2021 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-34576152

RESUMEN

Aryl hydrocarbon receptor (AHR) genomic pathway has been well-characterized in a number of respiratory diseases. In addition, the cytoplasmic AHR protein may act as an adaptor of E3 ubiquitin ligase. In this study, the physiological functions of AHR that regulate cell proliferation were explored using the CRISPR/Cas9 system. The doubling-time of the AHR-KO clones of A549 and BEAS-2B was observed to be prolonged. The attenuation of proliferation potential was strongly associated with either the induction of p27Kip1 or the impairment in mitogenic signal transduction driven by the epidermal growth factor (EGF) and EGF receptor (EGFR). We found that the leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1), a repressor of EGFR, was induced in the absence of AHR in vitro and in vivo. The LRIG1 tends to degrade via a proteasome dependent manner by interacting with AHR in wild-type cells. Either LRIG1 or a disintegrin and metalloprotease 17 (ADAM17) were accumulated in AHR-defective cells, consequently accelerating the degradation of EGFR, and attenuating the response to mitogenic stimulation. We also affirmed low AHR but high LRIG1 levels in lung tissues of chronic obstructive pulmonary disease (COPD) patients. This might partially elucidate the sluggish tissue repairment and developing inflammation in COPD patients.


Asunto(s)
Receptores ErbB/metabolismo , Glicoproteínas de Membrana/metabolismo , Mitógenos/metabolismo , Proteolisis , Receptores de Hidrocarburo de Aril/metabolismo , Transducción de Señal , Células A549 , Proteína ADAM17/metabolismo , Animales , Ciclo Celular/efectos de los fármacos , Puntos de Control del Ciclo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Clonales , Factor de Crecimiento Epidérmico/farmacología , Humanos , Pulmón/patología , Ratones Endogámicos C57BL , Ratones Noqueados , Proteolisis/efectos de los fármacos , Enfermedad Pulmonar Obstructiva Crónica/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/patología , Regulación hacia Arriba/efectos de los fármacos
15.
IEEE/ACM Trans Comput Biol Bioinform ; 17(6): 1981-1993, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31027048

RESUMEN

We present a fully closed-loop design for an artificial pancreas (AP) that regulates the delivery of insulin for the control of Type I diabetes. Our AP controller operates in a fully automated fashion, without requiring any manual interaction with the patient (e.g., in the form of meal announcements). A major obstacle to achieving closed-loop insulin control are the "unknown disturbances" related to various aspects of a patient's daily behavior, especially meals and physical activity. Such disturbances can significantly affect the patient's blood glucose levels. To handle such uncertainties, we present a data-driven, robust, model-predictive control framework in which we capture a wide range of individual meal and exercise patterns using uncertainty sets learned from historical data. These uncertainty sets are then used in the insulin controller to achieve automated, precise, and personalized insulin therapy. We provide an extensive in silico evaluation of our robust AP design, demonstrating the potential of the approach. In particular, without the benefit of explicit meal announcements, our approach can regulate glucose levels for large clusters of meal profiles learned from population-wide survey data and cohorts of virtual patients, even in the presence of high carbohydrate disturbances.


Asunto(s)
Aprendizaje Automático , Modelos Estadísticos , Páncreas Artificial , Glucemia/fisiología , Diabetes Mellitus Tipo 1/terapia , Humanos , Sistemas de Infusión de Insulina
16.
Chemphyschem ; 17(1): 93-7, 2016 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-26449719

RESUMEN

Functionalized ionic liquids are a subclass of ionic liquids that are tailored for a specific application. Structural characterization in both solid and liquid phases is central to understanding their physical properties. Here, we used ultralow-frequency Raman spectroscopy, which can measure Raman spectra down to approximately 5 cm(-1) , to study the structures and physical properties of 1-(4-cyanobenzyl)-3-methylimidazolium salts with five different anions. A comparison of the observed low-frequency Raman spectral patterns enabled us to predict the crystal symmetry of one of the synthesized salts for which single-crystal X-ray diffraction data were unobtainable. Real-time tracking of the low-frequency Raman spectral changes during melting revealed peak shifts indicative of different degrees of microscopic heterogeneity in the ionic liquids. The results show that our method provides a facile means that is complementary to X-ray crystallography, for obtaining structural information of ionic liquids.

17.
Acta Crystallogr D Biol Crystallogr ; 68(Pt 8): 953-9, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22868760

RESUMEN

The yeast Paf1 complex (Paf1C), which is composed of the proteins Paf1, Cdc73, Ctr9, Leo1 and Rtf1, accompanies RNA polymerase II from the promoter to the 3'-end formation site of mRNA- and snoRNA-encoding genes. As one of the first identified subunits of Paf1C, yeast Cdc73 (yCdc73) takes part in many transcription-related processes, including binding to RNA polymerase II, recruitment and activation of histone-modification factors and communication with other transcriptional activators. The human homologue of yCdc73, parafibromin, has been identified as a tumour suppressor linked to breast, renal and gastric cancers. However, the functional mechanism of yCdc73 has until recently been unclear. Here, a 2.2 Å resolution crystal structure of the highly conserved C-terminal region of yCdc73 is reported. It revealed that yCdc73 appears to have a GTPase-like fold. However, no GTPase activity was observed. The crystal structure of yCdc73 will shed new light on the modes of function of Cdc73 and Paf1C.


Asunto(s)
Cristalografía por Rayos X/métodos , GTP Fosfohidrolasas/química , Proteínas Nucleares/química , Proteínas de Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/enzimología , Secuencia de Aminoácidos , Clonación Molecular , Cristalización , Regulación Neoplásica de la Expresión Génica , Genes Supresores de Tumor , Histonas/química , Humanos , Datos de Secuencia Molecular , Neoplasias/metabolismo , Regiones Promotoras Genéticas , Estructura Terciaria de Proteína , ARN Polimerasa II/química , Saccharomyces cerevisiae/genética , Homología de Secuencia de Aminoácido
18.
Proteins ; 80(6): 1707-11, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22447656

RESUMEN

Agkisacucetin is a snake C-type lectin isolated from the venom of Agkistrodon acutus (A. acutus). It binds specifically to the platelet glycoprotein (GP) Ib and prevents the von Willebrand factor (VWF) accessing it. We determined the crystal structure of agkisacucetin to 1.9Å resolution. The structure of agkisacucetin has an (αß) fold similar to another GPIb-binding protein, flavocetin-A, but lacks the C-terminal cysteine in the ß-subunit, does not form (ßα)(4) tetramers, and does not cluster GPIbs, like flavocetin-A.


Asunto(s)
Venenos de Crotálidos/química , Lectinas Tipo C/química , Secuencia de Aminoácidos , Proteínas Sanguíneas/química , Proteínas Sanguíneas/metabolismo , Venenos de Crotálidos/metabolismo , Cristalografía por Rayos X , Lectinas Tipo C/metabolismo , Glicoproteínas de Membrana/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Inhibidores de Agregación Plaquetaria/química , Inhibidores de Agregación Plaquetaria/metabolismo , Conformación Proteica , Subunidades de Proteína , Alineación de Secuencia , Factor de von Willebrand
20.
Spectrochim Acta A Mol Biomol Spectrosc ; 71(4): 1485-91, 2008 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-18635391

RESUMEN

With radiation from a synchrotron we measured the spectra of several small molecular species, in the solid phase at 10K, either pure--O2, NO, CO2, N2O, H2O and NH3--or, for NH3, also dispersed in Ar at molar ratio 1/250, from the onset of absorption in the ultraviolet region until the limits of transmission by crystalline LiF or solid Ar. In a quantitative treatment of spectral data, we fitted the total absorption profile divided by wavenumber to Gaussian curves of minimal number, and made tentative assignments of electronic transitions and vibrational structure by comparison with spectra of gaseous species. These results illuminate the nature of electronic spectra of samples in solid phases in the vacuum ultraviolet region.


Asunto(s)
Espectrofotometría Ultravioleta/métodos , Absorción , Amoníaco/química , Argón , Dióxido de Carbono/química , Electroquímica/métodos , Electrónica , Óxido Nítrico/química , Distribución Normal , Oxígeno/química , Temperatura , Rayos Ultravioleta , Agua/química
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