structural analysis

结构分析
  • 文章类型: Journal Article
    主要组织相容性复合物(MHC)I类链相关A(MICA)在应激细胞识别中起重要作用。MICA的高多态性与NKG2D结合能力有关,NK细胞的反应和肿瘤进展。在这项研究中,使用PCR-SSP对97例胆管癌患者进行MICA基因分型。MICA*010与校正p值<0.001呈正相关(RR=2.16(95%CI,1.48-3.14))。MICA*010先前报道为未表达的等位基因。因此,使用不同的抗体克隆(1H10,1D10,1C3.1,1C3.2,6D4和3H5)在MICA*010转染的细胞(HEK293T和L929细胞)和从纯合MICA*010个体获得的刺激的原代单核细胞上研究了MICA*010在细胞表面的表达。令人惊讶的是,MICA*010的表达可以在转染的细胞和刺激的单核细胞上观察到,并有效地结合到NKG2D-Fc融合蛋白。各种MICA等位基因的功能研究表明,MICA*010转染的C1R细胞对NK细胞具有较高的相对杀伤活性,不遵循先前报道的M129V替换规则。结构分析突出显示位置36处的氨基酸是与保持MICA蛋白和NKG2D结合的结构完整性相关的另一个重要氨基酸。我们的数据提出了功能性MICA贡献基序的新方面,并且MICA*010对NK细胞功能具有潜在影响,并且可能适用于其他免疫应答领域。
    The major histocompatibility complex (MHC) class I chain-related A (MICA) plays an important role in stress cell recognition. High polymorphisms of MICA are relevant to NKG2D binding capacity, responses of NK cells and tumor progression. In this study, MICA genotyping of 97 cholangiocarcinoma patients was performed using PCR-SSP. MICA*010 was positively associated with a corrected p-value of < 0.001 (RR=2.16 (95 % CI, 1.48-3.14)). MICA*010 was previously reported as a non-expressed allele. Thus, the expression of MICA*010 on the cell surface was studied on both MICA*010 transfected cells (HEK 293 T and L929 cells) and stimulated primary monocytes obtained from homozygous MICA*010 individuals using different clones of antibodies (1H10, 1D10, 1C3.1, 1C3.2, 6D4 and 3H5) for detection. Surprisingly, the expression of MICA*010 could be observed on both transfected cells and stimulated monocytes and effectively bound to the NKG2D-Fc fusion protein. The functional study of various MICA alleles revealed the high relative killing activity of NK cells induced by the MICA*010 transfected C1R cells, not following the previously reported rule of the M129V substitution. The structural analysis highlighted the amino acid at position 36 as another important amino acid relevant to preserving the structural integrity of the MICA protein and NKG2D binding. Our data propose a new aspect of functional MICA contributing motifs and that MICA*010 has a potential effect on NK cell functions and might be applicable to other fields of immune responses.
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  • 文章类型: Journal Article
    目的:本文研究了冻干微丸中材料厚度对提高封装菌储存稳定性的关键作用。使用扫描电子显微镜(SEM)和X射线显微断层扫描(μCT)对从不同退火持续时间获得的不同厚度的冷冻干燥材料进行定量。然后将材料厚度与封装的细胞的储存稳定性相关联。
    方法:包含蔗糖,麦芽糊精,益生菌细胞在液氮中淬灭形成颗粒。粒料在经历冷冻干燥之前经历不同的退火持续时间。使用SEM和μCT定量材料厚度。通过测量CFU计数来评估富氧和贫氧环境中的储存稳定性,并将其与颗粒结构相关联。
    结果:不同的退火方案产生一系列材料厚度,更广泛的退火导致较厚的材料。储存稳定性与材料厚度呈正相关,表明使用较厚的材料改善了稳定性。未退火的颗粒表现出结构不规则性和不一致的储存稳定性,突出了在冷冻干燥过程中避免退火的不切实际。
    结论:大量退火不仅增强了益生菌产品的储存稳定性,而且对冷冻干燥过程提供了更大的控制,确保均匀和可重复的产品。这项研究强调了冻干颗粒中材料厚度对优化益生菌制剂储存稳定性的重要性。并强调退火作为冷冻干燥淬火颗粒的关键步骤的必要性,以实现所需的结构和稳定性结果。
    OBJECTIVE: This paper investigates the critical role of material thickness in freeze-dried pellets for enhancing the storage stability of encapsulated bacteria. Freeze dried material of varying thicknesses obtained from different annealing durations is quantified using Scanning Electron Microscopy (SEM) and X-ray microtomography (μCT), the material thickness is then correlated to the storage stability of the encapsulated cells.
    METHODS: A formulation comprising of sucrose, maltodextrin, and probiotic cells is quenched in liquid nitrogen to form pellets. The pellets undergo different durations of annealing before undergoing freeze-drying. The material thickness is quantified using SEM and μCT. Storage stability in both oxygen-rich and oxygen-poor environments is evaluated by measuring CFU counts and correlated with the pellet structure.
    RESULTS: The varying annealing protocols produce a range of material thicknesses, with more extensive annealing resulting in thicker materials. Storage stability exhibits a positive correlation with material thickness, indicating improved stability with thicker materials. Non-annealed pellets exhibit structural irregularities and inconsistent storage stability, highlighting the impracticality of avoiding annealing in the freeze-drying process.
    CONCLUSIONS: Extensive annealing not only enhances the storage stability of probiotic products but also provides greater control over the freeze-drying process, ensuring homogeneous and reproducible products. This study underscores the importance of material thickness in freeze-dried pellets for optimizing storage stability for probiotic formulations, and emphasize the necessity of annealing as a critical step in freeze-drying quenched pellets to achieve desired structural and stability outcomes.
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  • 文章类型: Journal Article
    果胶广泛用于食品和制药行业。然而,缺乏有关甘薯果胶提取和结构性质分析的数据。这里,用于农业加工废物的高价值利用,红薯渣,红薯淀粉加工的副产品,用作原材料。草酸铵,柠檬酸三钠,磷酸氢二钠,盐酸和柠檬酸被用作果胶成分的萃取剂,其中草酸铵对甘薯果胶的提取率高,低灰分和高分子量。对草酸铵提取的纯化甘薯果胶(AMOP)进行了结构和凝胶分析。分析表明AMOP是鼠李糖半乳糖醛酸-I型果胶,分子量为192.5kg/mol。化学滴定和红外光谱分析证实AMOP是一种低酯果胶,扫描电子和原子力显微镜显示了其线性分子结构。凝胶化研究表明,Ca2+是凝胶形成的关键因素,和蔗糖显著提高凝胶硬度。在pH4时观察到最高的AMOP凝胶硬度,Ca2+浓度为30mg/g,果胶浓度为2%,蔗糖浓度为40%,这些结果为甘薯果胶的生产和应用提供了基础。
    Pectin is widely used in the food and pharmaceutical industries. However, data on sweet potato pectin extraction and structural property analyses are lacking. Here, for the high-value utilization of agricultural processing waste, sweet potato residue, a byproduct of sweet potato starch processing, was used as raw material. Ammonium oxalate, trisodium citrate, disodium hydrogen phosphate, hydrochloric acid and citric acid were used as extractants for the pectin constituents, among which ammonium oxalate had a high extraction rate of sweet potato pectin, low ash content and high molecular weight. Structural and gelation analyses were conducted on ammonium oxalate-extracted purified sweet potato pectin (AMOP). Analyses showed that AMOP is a rhamnogalacturonan-I-type pectin, with a molecular weight of 192.5 kg/mol. Chemical titration and infrared spectroscopy analysis confirmed that AMOP is a low-ester pectin, and scanning electron and atomic force microscopy demonstrated its linear molecular structure. Gelation studies have revealed that Ca2+ is the key factor for gel formation, and that sucrose significantly enhanced gel hardness. The highest AMOP gel hardness was observed at pH 4, with a Ca2+ concentration of 30 mg/g, pectin concentration of 2%, and sucrose concentration of 40%, reaching 128.87 g. These results provide a foundation for sweet potato pectin production and applications.
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  • 文章类型: Journal Article
    这项研究解释了摩洛哥高地图集地块Tizin\'试验区的航磁数据,旨在深入了解其岩性结构架构以及对矿产勘探和开采的影响。我们对剩余磁场数据采用了六种不同的分析技术,包括减少到极点(RTP),向上延续,总水平导数,倾斜角度,勘探目标确定中心(CET)分析,和欧拉反卷积。我们的分析将研究区域分为三个磁畴:东部Ouzellarh块,以积极异常为特征,一个中央域,其特征是负磁特征,划定了由Ouchden断层隔开的反Atlas和高Atlas之间的过渡区:和西部域,以蒂奇卡地块为代表。总水平导数的应用,倾斜角度,和三元图像格式的过滤器组合(倾斜角度,向上延续1000+倾斜角度和向上延续3000+倾斜角度)揭示了已知和先前未确定的地质谱系,在不同方向上绘制结构复杂性(NE-SW,NNE-SSE,E-W,NW-SE,和N-S)。CET网格分析方法揭示了结构的复杂性,突出该地区的地球动力学演化。特别是,Ouchden断层描绘了古代高Atlas和Ouzellarh区块(反Atlas)之间的磁畴鸿沟。此外,Euler反卷积表明,磁源深度范围从Tichka地块西域的52m到Ouzellarh区块的6560m。全面的结构方案,通过C-A分形分析分类,确定有利于勘探和采矿的区域,尤其是Ouchden断层,Tizin\'测试,西北区域的NE-SW趋势线,以及沿着蒂奇卡花岗岩的边缘。
    This study interprets aeromagnetic data from the Tizi n\'Test area in the High Atlas massif of Morocco, aiming to gain insights into its litho-structural architecture and implications for mineral exploration and mining. We employed six different analytical techniques to the residual magnetic field data, including reduction to the pole (RTP), upward continuation, total horizontal derivative, Tilt angle, Centre for Exploration Targeting (CET) analysis, and Euler deconvolution. Our analyses differentiated the study area into three magnetic domains: the eastern Ouzellarh block, characterized by positive anomalies, a central domain characterized by a negative magnetic signature demarcating the transitional zone between the Anti-Atlas and the High Atlas separated by the Ouchden fault: and the western domain, represented by the Tichka massif. The application of total horizontal derivative, tilt angle, and a combination of filters in ternary image formats (Tilt angle, upward continuation 1000 + Tilt angle and upward continuation 3000 + Tilt angle) revealed both known and previously unidentified geological lineaments, mapping structural complexity across various orientations (NE-SW, NNE-SSE, E-W, NW-SE, and N-S). The CET grid analysis method unveiled the structural complexity, highlighting the geodynamic evolution of the region. Particularly, the Ouchden fault delineates a magnetic domain divide between the ancient High Atlas and the Ouzellarh block (Anti-Atlas). Furthermore, Euler deconvolution indicated magnetic source depths ranging from 52 m in the western domain of the Tichka massif to 6560 m in the Ouzellarh block. A comprehensive structural scheme, classified by C-A fractal analysis, identified zones favourable for exploration and mining, particularly along the Ouchden fault, Tizi n\'Test, NE-SW trending lineaments in the northwestern domain, as well as along the Tichka granite\'s margin.
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  • 文章类型: Journal Article
    β-葡萄糖苷酶是一种重要的纤维素酶,因为它的活性决定了纤维素水解成葡萄糖的效率。本研究探讨了profidaβ-葡萄糖苷酶(Tp-BGL)的功能和结构特征。Tp-BGL对对硝基苯基-β-d-吡喃葡萄糖苷(pNPGlc)的Km为0.3798mM,对纤维二糖的Km为4.44mM,kcat/Km分别为1211.16和4.18s-1mM-1。此外,Tp-BGL具有显著的pH适应性和热稳定性,Tm为85.7°C并且在80°C下孵育90分钟后保留>90%的其活性。Tp-BGL的晶体结构以1.95µ分辨率解析,并揭示了典型的TIM桶结构。比较结构分析强调Tp-BGL和其他葡糖苷酶之间的主要区别在于它们的环区。
    β-Glucosidase is a crucial cellulase, as its activity determines the efficiency of cellulose hydrolysis into glucose. This study addresses the functional and structural characteristics of Thermotoga profunda β-glucosidase (Tp-BGL). Tp-BGL exhibited a Km of 0.3798 mM for p-nitrophenyl-β-d-glucopyranoside (pNPGlc) and 4.44 mM for cellobiose, with kcat/Km of 1211.16 and 4.18 s-1 mM-1, respectively. In addition, Tp-BGL showed significant pH adaptability and thermal stability, with a Tm of 85.7 °C and retaining >90 % of its activity after incubation at 80 °C for 90 min. The crystal structure of Tp-BGL was resolved at 1.95 Å resolution, and reveals a typical TIM barrel structure. Comparative structural analysis highlighted that the major distinction between Tp-BGL and the other glucosidases lies in their loop regions.
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  • 文章类型: Journal Article
    为了更好地解决机械性能,有必要利用现代工具进行预测,模拟场景,优化决策。源整合。这将增加检测材料修改的能力,这些材料修改预示着损坏和/或预测将来很可能发生疲劳并扩展裂纹的阶段。通过协同实施基于NDE的协议来研究机械,疲劳和断裂行为而获得的预警结果将增强对经济上可持续的未来损害控制方案的准备。具体来说,这些预警结果将以重新拓扑模型的形式开发,并与FEA结合使用。本文介绍了校准的第一阶段和不同传感器系统的组合(摄影测量,激光扫描和应变计),用于创建适用于FEA软件故障预测的体积模型。测试对象是汽车悬架的两个组件,其上安装了应变仪以测量其在循环载荷下的变形。方法的校准是使用从摄影测量法和实验应变仪测量获得的模型进行的。
    To better address mechanical behavior, it is necessary to make use of modern tools through which it is possible to run predictions, simulate scenarios, and optimize decisions. sources integration. This will increase the capability of detecting material modifications that forerun damage and/or to forecast the stage in the future when very likely fatigue is initiating and propagating cracks. Early warning outcomes obtained by the synergetic implementation of NDE-based protocols for studying mechanical and fatigue and fracture behavior will enhance the preparedness toward economically sustainable future damage control scenarios. Specifically, these early warning outcomes will be developed in the form of retopologized models to be used coupled with FEA. This paper presents the first stage of calibration and the combination of a system of different sensors (photogrammetry, laser scanning and strain gages) for the creation of volumetric models suitable for the prediction of failure of FEA software. The test objects were two components of car suspension to which strain gauges were attached to measure its deformation under cyclic loading. The calibration of the methodology was carried out using models obtained from photogrammetry and experimental strain gauge measurements.
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  • 文章类型: Journal Article
    B细胞表位必须是可见的以被同源B细胞和/或抗体识别。这里,我们研究了从免疫表位数据库收集的已知线性B细胞表位的前提,这些表位在微生物感染期间被人类识别。我们发现大多数已知的B细胞表位是病毒特异性线性B细胞表位(87.96%),大多数位于保留在宿主细胞和/或病毒颗粒中的抗原中,防止抗体识别(29,225个表位中的18,832个)。此外,我们估计,在暴露的病毒区域中发现的病毒特异性线性B细胞表位中只有少数(32.72%)(例如,包膜蛋白的胞外域)在完整抗原上是溶剂可及的。因此,我们得出的结论是,病毒颗粒和/或感染细胞的充分降解/处理必须在B细胞识别之前发生,从而形成B细胞表位库。
    B cell epitopes must be visible for recognition by cognate B cells and/or antibodies. Here, we studied that premise for known linear B cell epitopes that were collected from the Immune Epitope Database as being recognized by humans during microbial infections. We found that the majority of such known B cell epitopes are virus-specific linear B cell epitopes (87.96%), and most are located in antigens that remain enclosed in host cells and/or virus particles, preventing antibody recognition (18,832 out of 29,225 epitopes). Moreover, we estimated that only a minority (32.72%) of the virus-specific linear B cell epitopes that are found in exposed viral regions (e.g., the ectodomains of envelope proteins) are solvent accessible on intact antigens. Hence, we conclude that ample degradation/processing of viral particles and/or infected cells must occur prior to B cell recognition, thus shaping the B cell epitope repertoire.
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  • 文章类型: Journal Article
    胰岛素超家族蛋白(ISP),特别是,胰岛素,IGF和松弛素蛋白是动物生理学的关键调节剂。已知它们是从相同的祖先基因进化而来的,并分化为具有不同序列和不同功能的蛋白质,但保持高度保守的二硫桥稳定的类似结构架构。最近的序列数据和这些蛋白质的结构激增,促使人们需要进行全面分析,根据可用的功能和结构信息,包括ISP的代表性复杂结构及其同源受体,将这些序列(427序列)的进化联系起来。该研究揭示了(a)IGFs异常高的序列保守性(在184个序列中保守性>90%),并为这种高序列保守性提供了可能的基于结构的基本原理;(b)提供了功能多样的松弛素家族成员的受体结合特征基序的更新定义;(c)在一些胰岛素序列中提供了可能的非常规C肽切割位点。IGFs的高度保守性似乎代表了对与多个伴侣的生理重要相互作用所产生的序列多样性的抵抗的经典案例。我们还提出了在一些不同的胰岛素序列中切割C肽的可能机制,并重新定义了松弛素家族的受体结合特征基序。最后,我们为具有潜在治疗应用的最小修饰胰岛素突变体提供了基础,受分子动力学模拟支持的其他胰岛素超家族蛋白成员中观察到的伴随变化的启发。
    The insulin superfamily proteins (ISPs), in particular, insulin, IGFs and relaxin proteins are key modulators of animal physiology. They are known to have evolved from the same ancestral gene and have diverged into proteins with varied sequences and distinct functions, but maintain a similar structural architecture stabilized by highly conserved disulphide bridges. The recent surge of sequence data and the structures of these proteins prompted a need for a comprehensive analysis, which connects the evolution of these sequences (427 sequences) in the light of available functional and structural information including representative complex structures of ISPs with their cognate receptors. This study reveals (a) unusually high sequence conservation of IGFs (>90 % conservation in 184 sequences) and provides a possible structure-based rationale for such high sequence conservation; (b) provides an updated definition of the receptor-binding signature motif of the functionally diverse relaxin family members (c) provides a probable non-canonical C-peptide cleavage site in a few insulin sequences. The high conservation of IGFs appears to represent a classic case of resistance to sequence diversity exerted by physiologically important interactions with multiple partners. We also propose a probable mechanism for C-peptide cleavage in a few distinct insulin sequences and redefine the receptor-binding signature motif of the relaxin family. Lastly, we provide a basis for minimally modified insulin mutants with potential therapeutic application, inspired by concomitant changes observed in other insulin superfamily protein members supported by molecular dynamics simulation.
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  • 文章类型: Journal Article
    这项研究对具有不同单位的连接葡萄糖分子的模拟直链淀粉的结构分析和计算拉曼光谱进行了量子化学研究。我们系统地检查了这些直链淀粉模型中羟甲基和分子内氢键的旋转。我们的研究发现,随着连接的葡萄糖单位数量的增加,线性结构变得更加复杂,导致卷曲,循环,或通过建立各种分子内相互作用促进的螺旋结构。确认羟甲基与氧原子以及与分子结构中相邻环的羟甲基和羟基形成相互作用。通过比较其计算的拉曼光谱,我们确定了适用于各种分析环境的不同峰和选择的特定带。在不同长度的直链淀粉模型中鉴定了选定区域内的代表性振动模式,作为线性和更卷曲的结构构象的特征标志。我们的发现有助于更深入地了解直链淀粉结构和光谱特征,对理论研究和潜在应用具有重要意义。这项工作为直链淀粉结构的拉曼峰的详细分配提供了有价值的参考点,促进它们在碳水化合物结构及其相关光谱特性的更广泛研究中的应用。
    This study presents a quantum chemical investigation into the structural analysis and calculated Raman spectra of modeled amylose with varying units of linked glucose molecules. We systematically examined the rotation of hydroxymethyl groups and intramolecular hydrogen bonds within these amylose models. Our study found that as the number of linked glucose units increases, the linear structure becomes more complex, resulting in curled, cyclic, or helical structures facilitated by establishing various intramolecular interactions. The hydroxymethyl groups were confirmed to form interactions with oxygen atoms and with hydroxymethyl and hydroxyl groups from adjacent rings in the molecular structures. We identified distinct peaks and selected specific bands applicable in various analytical contexts by comparing their calculated Raman spectra. Representative vibrational modes within selected regions were identified across the different lengths of amylose models, serving as characteristic signatures for linear and more coiled structural conformations. Our findings contribute to a deeper understanding of amylose structures and spectroscopic signatures, with implications for theoretical studies and potential applications. This work provides valuable reference points for the detailed assignment of Raman peaks of amylose structure, facilitating their application in broader research on carbohydrate structures and their associated spectroscopic properties.
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  • 文章类型: Journal Article
    双酚A(BPA)和双酚B(BPB)广泛应用于塑料生产中,以及它们对健康的潜在不良影响,特别是内分泌干扰和代谢健康,引起了关注。过氧化物酶体增殖物激活受体γ(PPARγ)在代谢调节和脂肪形成中起关键作用,使其成为了解肥胖发展和相关健康影响的目标。在这项研究中,我们使用X射线晶体学和分子动力学(MD)模拟来研究PPARγ与BPA和BPB的相互作用。晶体结构揭示了BPA和BPB与PPARγ配体结合域的结合,其次是C285,其中先前已经观察到PPARγ信号传导的部分激动剂以及拮抗剂和反向激动剂的结合。然而,在激活功能2位点未观察到BPA和BPB与Y437的相互作用,表明这些配体不能直接稳定螺旋12的活性构象。此外,MD模拟的自由能分析表明,I341对本研究中表征的BPA和BPB结合模式具有很大的能量贡献。
    Bisphenol A (BPA) and bisphenol B (BPB) are widely used in the production of plastics, and their potential adverse health effects, particularly on endocrine disruption and metabolic health, have raised concern. Peroxisome proliferator-activated receptor gamma (PPARγ) plays a pivotal role in metabolic regulation and adipogenesis, making it a target of interest in understanding the development of obesity and associated health impacts. In this study, we employ X-ray crystallography and molecular dynamics (MD) simulations to study the interaction of PPARγ with BPA and BPB. Crystallographic structures reveal the binding of BPA and BPB to the ligand binding domain of PPARγ, next to C285, where binding of partial agonists as well as antagonists and inverse agonists of PPARγ signaling has been previously observed. However, no interaction of BPA and BPB with Y437 in the activation function 2 site is observed, showing that these ligands cannot stabilize the active conformation of helix 12 directly. Furthermore, free energy analyses of the MD simulations revealed that I341 has a large energetic contribution to the BPA and BPB binding modes characterized in this study.
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