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Tetrahydroquinoline/4,5-dihydroisoxazoline derivatives counteract multidrug resistance in cancer cells by inhibiting P-glycoprotein (ABCB1)-mediated transport 四氢喹啉/4,5-二氢异恶唑啉衍生物通过抑制p -糖蛋白(ABCB1)介导的转运来对抗癌细胞的多药耐药。
IF 2.2 3区 生物学 Q3 BIOCHEMISTRY & MOLECULAR BIOLOGY Pub Date : 2025-12-04 DOI: 10.1016/j.bbagen.2025.130894
Marina Hembecker , Diogo Henrique Kita , Azam Rashidian , Luis C. Vesga , Bruna Estelita Ruginsk , Arnold R. Romero Bohórquez , Stelia Carolina Mendez-Sanchez , Vinicius Goncalves Maltarollo , Fabiane Gomes de Moraes Rego , Geraldo Picheth , Antti Poso , Katalin Goda , Suresh V. Ambudkar , Vivian Rotuno Moure , Thales Kronenberger , Glaucio Valdameri
Cancer treatment is challenged by the emergence of multidrug resistance (MDR). MDR is often caused by the overexpression of certain ABC transporters, such as P-glycoprotein (P-gp, ABCB1) in the plasma membrane of tumor cells and tumor stem cells. Inhibition of ABC transporter-mediated efflux of anticancer drugs might be a plausible approach to overcome MDR. Here, we studied the interaction of 16 tetrahydroquinoline/4,5-dihydroisoxazole derivatives (A1 - D4) with human P-gp to identify and characterize new P-gp inhibitors. We found that compounds C1 and D1 inhibited the P-gp-mediated efflux of rhodamine 123 (R123), with IC50 values of 41.5 and 6.6 μM, respectively. Both compounds showed low cytotoxicity on NIH3T3 and NIH3T3-ABCB1 cells over a broad concentration range. Interestingly, C1 and D1 increased the ATPase activity of P-gp at sub-micromolar concentrations, showing EC50 values of 0.17 and 0.62 μM, respectively. However, thermal inactivation and UIC2 reactivity assays supported that, similar to potent P-gp inhibitors, C1 and D1 can hinder the dimerization of the nucleotide binding domains (NBDs), when applied at higher concentrations (≥10 μM). In addition, docking studies showed that D1 preferentially interacts with the central substrate binding cavity of P-gp. Finally, D1 chemosensitized drug-resistant KB-V1 cells overexpressing P-gp. In view of our previous findings that C1 and D1 also inhibit ABCG2 and MRP1, they can be considered as novel pan-ABC transporter inhibitors offering potential for treating chemotherapy-resistant tumors.
多药耐药(MDR)的出现对癌症治疗提出了挑战。MDR通常是由肿瘤细胞和肿瘤干细胞质膜中p -糖蛋白(P-gp, ABCB1)等某些ABC转运蛋白的过度表达引起的。抑制ABC转运蛋白介导的抗癌药物外排可能是克服耐多药耐药的可行方法。在这里,我们研究了16种四氢喹啉/4,5-二氢异恶唑衍生物(A1 - D4)与人P-gp的相互作用,以鉴定和表征新的P-gp抑制剂。我们发现化合物C1和D1抑制p- gp介导的罗丹明123 (R123)的外排,IC50值分别为41.5和6.6 μM。两种化合物在较宽的浓度范围内对NIH3T3和NIH3T3- abcb1细胞均表现出较低的细胞毒性。有趣的是,C1和D1在亚微摩尔浓度下增加P-gp的atp酶活性,EC50值分别为0.17和0.62 μM。然而,热失活和UIC2反应性分析表明,与强效P-gp抑制剂类似,C1和D1在较高浓度(≥10 μM)下可以阻碍核苷酸结合域(NBDs)的二聚化。此外,对接研究表明D1优先与P-gp的中心底物结合腔相互作用。最后,D1使耐药KB-V1细胞过表达P-gp。鉴于我们之前的研究发现C1和D1也抑制ABCG2和MRP1,它们可以被认为是新的泛abc转运蛋白抑制剂,为治疗化疗耐药肿瘤提供了潜力。
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引用次数: 0
Development of benzoxazole-2-yl-guanidine based Cu (II), Co (II), and Ni (II) complexes: Structural features, physicochemical aspects underpinning their pharmaceutical potential supported with theoretical approaches 基于苯并恶唑-2-基胍的Cu (II), Co (II)和Ni (II)配合物的发展:结构特征,物理化学方面支持其药物潜力的理论方法支持。
IF 2.2 3区 生物学 Q3 BIOCHEMISTRY & MOLECULAR BIOLOGY Pub Date : 2025-12-04 DOI: 10.1016/j.bbagen.2025.130893
Ahmed M. Abu-Dief , Samar B. Mohamed , Mehran Feizi-Dehnayebi , Inam Omar , Manara A. Ayoub , Maher Fathalla , Mahmoud Abd El Aleem Ali Ali El-Remaily
In this study, novel bioactive metal complexes of Cu (II), Co (II), and Ni (II) were synthesized using a guanidine-based ligand, 1,3-benzoxazole-2-yl-guanidine (L). The resulting coordination compounds [Cu(L)(CH₃COO)₂(H₂O)]·2H₂O, [Co(L)(NO₃)₂(H₂O)]·3H₂O, and [Ni(L)(NO₃)₂(H₂O)]·H₂O were comprehensively characterized using a range of physicochemical and spectroscopic techniques, including UV–visible spectrophotometry, FT-IR spectroscopy, elemental analysis, molar conductance, MS analysis, TGA, and magnetic measurements. The collected data support the formation of octahedral geometries around the metal centers, highlighting the ligand's flexible coordination behavior. Density functional theory (DFT) calculations were employed to optimize the molecular structures and support the experimental findings. Solution characterization established stoichiometric relationships, equilibrium constants, and pH-dependent properties, indicating their robustness in aqueous environments. The biological potential of the synthesized compounds was further evaluated through in vitro cytotoxicity assays (MTT) against HepG2 (liver), MCF-7 (breast), and HCT-116 (colon) cancer cell lines. Among the tested compounds, the Cu (II)-L complex exhibited the most pronounced antiproliferative activity, particularly against MCF-7 cells. Antioxidant capacity, assessed via DPPH radical scavenging assay, confirmed the strong free-radical neutralizing potential of the metal chelates. Antimicrobial investigations demonstrated broad-spectrum activity against various pathogenic strains, including S. marcescens, M. luteus, E. coli, C. albicans, A. flavus, and F. oxysporum. Notably, the copper complex exhibited significant antibacterial activity against M. luteus and potent antifungal effects against F.oxysporum. These effects highlight the therapeutic promise of guanidine-derived metal chelates as multifunctional agents with potential applications in anticancer, antioxidant, and antimicrobial therapies.
本研究以1,3-苯并恶唑-2-基胍(L)为配体,合成了Cu (II)、Co (II)和Ni (II)的新型生物活性金属配合物。所得到的配位化合物[Cu(L)(CH₃COO)₂(H₂O)]·2H₂O, [Co(L)(NO₃)₂(H₂O))]·3H₂O和[Ni(L)(NO₃)₂(H₂O)]·H₂O使用一系列物理化学和光谱技术进行了全面表征,包括紫外可见分光光度法、FT-IR光谱、元素分析、摩尔电导、质谱分析、TGA和磁测量。收集到的数据支持围绕金属中心形成八面体几何形状,突出了配体的柔性配位行为。利用密度泛函理论(DFT)对分子结构进行优化,支持实验结果。溶液表征建立了化学计量关系、平衡常数和ph依赖性质,表明它们在水环境中的稳健性。通过对HepG2(肝脏)、MCF-7(乳腺)和HCT-116(结肠癌)细胞系的体外细胞毒试验(MTT)进一步评价合成化合物的生物学潜力。在所测试的化合物中,Cu (II)-L复合物表现出最明显的抗增殖活性,特别是对MCF-7细胞。通过DPPH自由基清除试验评估抗氧化能力,证实了金属螯合剂具有很强的自由基中和潜力。抗菌研究显示对多种致病菌株具有广谱活性,包括粘质葡萄球菌、黄体芽孢杆菌、大肠杆菌、白色念珠菌、黄芽孢杆菌和尖孢杆菌。值得注意的是,铜配合物对黄体镰刀菌和尖孢镰刀菌均有明显的抑菌活性。这些作用突出了胍衍生金属螯合物作为多功能药物在抗癌、抗氧化和抗菌治疗方面的潜在应用前景。
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引用次数: 0
Osmotic stress suppresses osteogenic differentiation by inhibiting nuclear translocation of YAP via perinuclear actin accumulation 渗透胁迫通过核周肌动蛋白积累抑制YAP的核易位,从而抑制成骨分化。
IF 2.2 3区 生物学 Q3 BIOCHEMISTRY & MOLECULAR BIOLOGY Pub Date : 2025-11-27 DOI: 10.1016/j.bbagen.2025.130891
Takashi Miyano, Haruka Hasegawa, Toshihiro Sera
Hyperglycemia is a well-recognized cause of osteoblast dysfunction. Recent evidence, however, indicates that elevated extracellular osmolarity associated with hyperglycemia may independently impair osteogenic differentiation. However, the mechanisms underlying these effects remain poorly understood. In this study, we examined how osmotic stress influences osteoblast differentiation, with a focus on actin cytoskeletal remodeling and subcellular localization of the Yes-associated protein (YAP), a mechanosensitive transcriptional coactivator involved in osteogenesis. Using MC3T3-E1 pre-osteoblasts, we found that osteogenic induction enhanced cell proliferation, migration, nuclear deformation, and nuclear translocation of YAP, accompanied by upregulated expression of genes encoding osteogenic markers. In contrast, treatment with either glucose or mannitol, used to isolate the osmotic component of hyperglycemia, preserved nuclear morphology, decreased nuclear localization of YAP, and led to perinuclear actin accumulation, as confirmed by radial profile analysis of actin distribution. These effects were accompanied by downregulation of target genes of YAP and reduction in alkaline phosphatase (ALP)-positive cells. Similar effects observed following treatments with both glucose and mannitol suggest that the impairment arises primarily from osmotic stress rather than from glucose-specific metabolic signaling. Notably, pharmacological inhibition of Rho-associated kinase using Y-27632 attenuated perinuclear actin accumulation, restored nuclear translocation of YAP, and rescued the expression of YAP-dependent osteogenic genes under osmotic conditions. Y-27632 also increased the number of ALP-positive cells after treatment with both glucose and mannitol. These findings underscore cytoskeletal remodeling as a central regulator of YAP activity and osteogenesis under osmotic stress, and propose potential therapeutic targets for skeletal fragility in diabetes.
高血糖是成骨细胞功能障碍的一个公认的原因。然而,最近的证据表明,与高血糖相关的细胞外渗透压升高可能独立地损害成骨分化。然而,这些影响背后的机制仍然知之甚少。在这项研究中,我们研究了渗透应激如何影响成骨细胞分化,重点关注肌动蛋白细胞骨架重塑和yes相关蛋白(YAP)的亚细胞定位,YAP是一种参与成骨的机械敏感转录辅助激活因子。利用MC3T3-E1前成骨细胞,我们发现成骨诱导增强了YAP的细胞增殖、迁移、核变形和核易位,并伴有编码成骨标记基因的表达上调。相比之下,葡萄糖或甘露醇处理,用于分离高血糖的渗透成分,保留核形态,降低YAP的核定位,并导致核周围肌动蛋白积累,这一点得到了肌动蛋白分布的径向剖面分析的证实。这些作用伴随着YAP靶基因的下调和碱性磷酸酶(ALP)阳性细胞的减少。葡萄糖和甘露醇治疗后观察到的类似效果表明,损伤主要是由渗透应激引起的,而不是由葡萄糖特异性代谢信号引起的。值得注意的是,使用Y-27632对rho相关激酶的药理抑制可减轻核周围肌动蛋白的积累,恢复YAP的核易位,并在渗透条件下恢复YAP依赖性成骨基因的表达。经葡萄糖和甘露醇处理后,Y-27632也增加了alp阳性细胞的数量。这些发现强调了细胞骨骼重塑是渗透应激下YAP活性和成骨的中心调节因子,并提出了糖尿病骨骼脆性的潜在治疗靶点。
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引用次数: 0
Ursolic acid activates SIRT6 by enhancing enzyme-substrate interactions and promoting protein structural rearrangement 熊果酸通过增强酶-底物相互作用和促进蛋白质结构重排来激活SIRT6
IF 2.2 3区 生物学 Q3 BIOCHEMISTRY & MOLECULAR BIOLOGY Pub Date : 2025-11-26 DOI: 10.1016/j.bbagen.2025.130890
Zohreh Tabatabaian Nimavard , Nuredin Bakhtiari , Fereshteh Taghavi , Sako Mirzaie , Farangis Ataei , Hamid-Reza Khaledi
Ursolic acid (UA) has emerged as a promising bioactive compound with potential therapeutic effects, particularly in the upregulation of SIRT6, an important protein involved in various cellular processes, including longevity, stress response, and metabolism. Despite the growing interest in UA and its beneficial biological activities, the precise mechanisms governing its interaction with SIRT6 remain inadequately elucidated. This study aims to conduct a comprehensive investigation into the binding affinity of UA to SIRT6, as well as its effects on the protein's stability, kinetics, and structural characteristics.
Molecular dynamics simulations using Schrodinger software analyzed parameters such as radius of gyration, RMSD, RMSF, and binding energy. The SIRT6 gene was cloned into the pET28a vector, expressed in Escherichia coli, and purified via affinity chromatography. Kinetic parameters (Km, Vmax, and Kcat) were assessed using fluorescence enzyme assays, while structural modifications were examined via fluorescence spectroscopy, FTIR, and UV–visible spectrophotometry.
UA significantly enhances SIRT6 stability, reducing its radius of gyration and lowering binding energy from −25.38 to −47.93 kcal/mol. Kinetic analysis revealed a decrease in Km (13 to 10), an increase in Vmax (5013.42 to 9421.48 μM/min), and a rise in Kcat (15.03/s to 281.01/s), improving the Kcat/Km ratio. Structural assessments confirmed UA-induced modifications, increasing alpha-helix content (8.5 % to 26.2 %) and elevating the folding ratio from 0.066 to 14.8. However, it decreased aggregation index from 402.38 to 81.25. This integrative study elucidates UA's molecular influence on SIRT6, underscoring its potential therapeutic relevance across various signaling pathways.
熊果酸(UA)已成为一种具有潜在治疗作用的生物活性化合物,特别是在SIRT6上调方面,SIRT6是一种重要的蛋白质,参与各种细胞过程,包括长寿、应激反应和代谢。尽管人们对UA及其有益的生物活性越来越感兴趣,但控制其与SIRT6相互作用的确切机制仍未充分阐明。本研究旨在全面探讨UA与SIRT6的结合亲和力及其对SIRT6蛋白稳定性、动力学和结构特性的影响。使用薛定谔软件进行分子动力学模拟,分析了旋转半径、RMSD、RMSF和结合能等参数。将SIRT6基因克隆到pET28a载体中,在大肠杆菌中表达,并通过亲和层析纯化。动力学参数(Km、Vmax和Kcat)采用荧光酶测定法评估,结构修饰通过荧光光谱、FTIR和紫外可见分光光度法检测。UA显著增强了SIRT6的稳定性,降低了SIRT6的旋转半径,并将结合能从- 25.38 kcal/mol降低到- 47.93 kcal/mol。动力学分析结果表明,Kcat/Km比值提高,Km减小(13 ~ 10),Vmax增大(5013.42 ~ 9421.48 μM/min), Kcat增大(15.03 ~ 281.01/s), Kcat/Km比值提高。结构评估证实了ua引起的修饰,增加了α -螺旋含量(8.5%至26.2%),并将折叠比从0.066提高到14.8。但其聚集指数从402.38下降到81.25。这项综合研究阐明了UA对SIRT6的分子影响,强调了其在各种信号通路中的潜在治疗相关性。
{"title":"Ursolic acid activates SIRT6 by enhancing enzyme-substrate interactions and promoting protein structural rearrangement","authors":"Zohreh Tabatabaian Nimavard ,&nbsp;Nuredin Bakhtiari ,&nbsp;Fereshteh Taghavi ,&nbsp;Sako Mirzaie ,&nbsp;Farangis Ataei ,&nbsp;Hamid-Reza Khaledi","doi":"10.1016/j.bbagen.2025.130890","DOIUrl":"10.1016/j.bbagen.2025.130890","url":null,"abstract":"<div><div>Ursolic acid (UA) has emerged as a promising bioactive compound with potential therapeutic effects, particularly in the upregulation of SIRT6, an important protein involved in various cellular processes, including longevity, stress response, and metabolism. Despite the growing interest in UA and its beneficial biological activities, the precise mechanisms governing its interaction with SIRT6 remain inadequately elucidated. This study aims to conduct a comprehensive investigation into the binding affinity of UA to SIRT6, as well as its effects on the protein's stability, kinetics, and structural characteristics.</div><div>Molecular dynamics simulations using Schrodinger software analyzed parameters such as radius of gyration, RMSD, RMSF, and binding energy. The SIRT6 gene was cloned into the pET28a vector, expressed in <em>Escherichia coli</em>, and purified via affinity chromatography. Kinetic parameters (Km, Vmax, and Kcat) were assessed using fluorescence enzyme assays, while structural modifications were examined via fluorescence spectroscopy, FTIR, and UV–visible spectrophotometry.</div><div>UA significantly enhances SIRT6 stability, reducing its radius of gyration and lowering binding energy from −25.38 to −47.93 kcal/mol. Kinetic analysis revealed a decrease in Km (13 to 10), an increase in Vmax (5013.42 to 9421.48 μM/min), and a rise in Kcat (15.03/s to 281.01/s), improving the Kcat/Km ratio. Structural assessments confirmed UA-induced modifications, increasing alpha-helix content (8.5 % to 26.2 %) and elevating the folding ratio from 0.066 to 14.8. However, it decreased aggregation index from 402.38 to 81.25. This integrative study elucidates UA's molecular influence on SIRT6, underscoring its potential therapeutic relevance across various signaling pathways.</div></div>","PeriodicalId":8800,"journal":{"name":"Biochimica et biophysica acta. General subjects","volume":"1870 2","pages":"Article 130890"},"PeriodicalIF":2.2,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145623196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Cavin-3 promotes TNF expression via the MAPK signaling pathway in lung squamous cell carcinoma 在肺鳞癌中,Cavin-3通过MAPK信号通路促进TNF的表达。
IF 2.2 3区 生物学 Q3 BIOCHEMISTRY & MOLECULAR BIOLOGY Pub Date : 2025-11-26 DOI: 10.1016/j.bbagen.2025.130892
Xiaoyan Xu , Yonghong Nie , Jiatuo Xu , Rilei Jiang
Cavin family proteins alter the invasiveness of tumor cells. However, research on the pathogenesis of Cavins in tumors is lacking. To address this knowledge-gap, we conducted a systematic analysis about the mechanism of action of Cavins in cancer. We evaluated the diagnostic value of Cavin-3 and its potential as a new therapeutic target for lung squamous cell carcinoma (LUSC). Bioinformatic analysis showed that Cavin-3 can inhibit LUSC tumor cells by regulating the expression of EREG and IL1A, thereby activating the MAPK pathway to promote the release of tumor necrosis factor (TNF) and other inflammatory factors. Moreover, in vitro experiments have shown that Cavin-3 may promote the expression of inflammatory factors by regulating the MAPK signaling pathway, thereby killing tumor cells and inhibiting tumor proliferation.
Cavin家族蛋白改变肿瘤细胞的侵袭性。然而,对Cavins在肿瘤中的发病机制的研究尚缺乏。为了解决这一知识空白,我们对Cavins在癌症中的作用机制进行了系统的分析。我们评估了Cavin-3的诊断价值及其作为肺鳞状细胞癌(LUSC)新治疗靶点的潜力。生物信息学分析表明,Cavin-3可以通过调节EREG和IL1A的表达,从而激活MAPK通路,促进肿瘤坏死因子(tumor necrosis factor, TNF)等炎症因子的释放,从而抑制LUSC肿瘤细胞。此外,体外实验表明,Cavin-3可能通过调节MAPK信号通路促进炎症因子的表达,从而杀伤肿瘤细胞,抑制肿瘤增殖。
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引用次数: 0
Decoding chromatin nanoscale plasticity in situ: Insights from native AFM imaging 解码染色质纳米级塑性原位:来自原生AFM成像的见解。
IF 2.2 3区 生物学 Q3 BIOCHEMISTRY & MOLECULAR BIOLOGY Pub Date : 2025-11-19 DOI: 10.1016/j.bbagen.2025.130887
Hongfeng Cui, Yu Zhang, Tianyu Chen, Mengzhu Guo, Qi Wen, Jiawei Peng, Yifei Yang, Xian Hao
Chromatin structure and its plasticity are central to gene regulation and DNA-associated processes, yet their nanoscale architecture and dynamic assembly remain elusive. Here, we propose a novel in situ approach—combining hypotonic treatment with high-drop spreading—to obtain native, naked chromosomes and visualize chromatin fine structure using atomic force microscopy (AFM). This strategy enables minimally invasive observation of chromatin under near-physiological conditions. We reveal that chromatin is composed of ∼10 nm DNA–histone particles as its fundamental units. Strikingly, these particles exhibit remarkable structural plasticity, dynamically assembling into heterogeneous nucleosome-beaded chains through stacking and partial melting. This challenges the classical “beads-on-a-string” model by demonstrating that chromatin is neither uniform nor static, but structurally versatile at the nanoscale. In addition, we investigated how histone acetylation and ATP modulate chromatin plasticity. Our findings highlight the coexistence of core particle stability and spatial-temporal variability, providing a revised molecular framework for chromatin's functional adaptability. These insights offer a fresh perspective on how chromatin structural diversity underpins its complex regulatory capacity.
染色质结构及其可塑性是基因调控和dna相关过程的核心,但其纳米级结构和动态组装仍然难以捉摸。在这里,我们提出了一种新的原位方法-结合低渗处理和高滴扩散-获得天然的,裸露的染色体,并使用原子力显微镜(AFM)观察染色质精细结构。这种策略可以在接近生理条件下对染色质进行微创观察。我们发现染色质是由~10 nm的dna组蛋白颗粒组成的基本单位。引人注目的是,这些颗粒表现出显著的结构可塑性,通过堆叠和部分熔化动态地组装成异质核小体串珠链。通过证明染色质既不是均匀的也不是静态的,而是在纳米尺度上结构多样,这挑战了经典的“串珠”模型。此外,我们还研究了组蛋白乙酰化和ATP如何调节染色质可塑性。我们的发现强调了核心颗粒稳定性和时空变异性的共存,为染色质的功能适应性提供了一个修订的分子框架。这些见解为染色质结构多样性如何支撑其复杂的调控能力提供了新的视角。
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引用次数: 0
Receptor binding domain of SARS CoV2 spike protein exhibits in vitro liquid-liquid phase separation due to structural disorderedness that may challenge the vaccine-generated antibody binding SARS CoV2刺突蛋白受体结合域由于结构紊乱可能挑战疫苗产生的抗体结合,在体外表现出液-液相分离。
IF 2.2 3区 生物学 Q3 BIOCHEMISTRY & MOLECULAR BIOLOGY Pub Date : 2025-11-19 DOI: 10.1016/j.bbagen.2025.130889
Manikanta Sodasani , Abhinav V.K.S. Grandhi , Niharikha Mukala , Jahnavi Chintalapati , Madhuri Vissapragada , Madhumita Aggunna , Ravikiran S. Yedidi
In this study we expressed, purified and demonstrated the protein liquid-liquid phase separation (LLPS) formation by the receptor binding domain (RBD) of coronavirus spike protein in vitro.
Our molecular dynamics simulations revealed multiple structurally disordered regions lacking secondary structural elements within RBD that exhibited high structural flexibility with deviations as high as 6 Å over 500 ns in support of our in vitro findings.
Additionally these disordered regions overlap with epitopes potentially altering their architecture.
Based on these results we conclude that the structural disorderedness of RBD causes LLPS formation in vitro and may potentially challenge the COVID-19 vaccine efficacy.
本研究在体外表达、纯化并证明了冠状病毒刺突蛋白受体结合域(RBD)形成的蛋白液-液相分离(LLPS)。我们的分子动力学模拟显示,RBD中缺乏二级结构元件的多个结构紊乱区域具有高结构灵活性,偏差高达6 Å超过500 ns,支持我们的体外研究结果。此外,这些无序区域与表位重叠,可能会改变它们的结构。基于这些结果,我们得出结论,RBD结构紊乱导致体外LLPS形成,并可能潜在地挑战COVID-19疫苗的功效。
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引用次数: 0
The effect of gold nanoparticle size and shape on the structure and activity of Domain 3 of an alternative sigma factor of Staphylococcus aureus 金纳米颗粒的大小和形状对金黄色葡萄球菌一个备选sigma因子结构域3结构域的结构和活性的影响。
IF 2.2 3区 生物学 Q3 BIOCHEMISTRY & MOLECULAR BIOLOGY Pub Date : 2025-11-19 DOI: 10.1016/j.bbagen.2025.130888
Tanaya Chatterjee, Debasmita Sinha

Background

The modern era has witnessed the vast applications of nanoparticles (NPs) ranging from drug delivery to biomedical usages. Herein we report for the first time the effect of gold nanoparticles (AuNPs) of different sizes and shapes on a stress response protein σB from Staphylococcus aureus, the pathogen causing infection. Among the three conserved domains of σB, we focused on Domain 3 which binds to an anti-sigma factor RsbW of S. aureus.

Methods

We explored the interaction of recombinant σB3 (rσB3) with three types of AuNPs; spherical with 10 nm (AuNS10) and 100 nm (AuNS100) diameter and rod shaped (AuNR10). Structural modulations of rσB3 by AuNPs were studied using different biophysical techniques. Native-PAGE was run for rσB3-cRsbW binding assay using AuNR10.

Results

Isothermal titration calorimetry revealed exothermic and endothermic heat changes for rσB3-AuNSs and rσB3-AuNR, respectively. Far-UV CD of rσB3 showed loss of α-helical content with AuNR10 using higher molar ratios of 1:5 and 1:10. Binding to 4,4′-dianilino-1,1′-binaphthyl-5,5′-disulfonic acid (bis-ANS) indicated enhanced fluorescence intensity for rσB3-AuNR10 conjugate, implying unfolding of rσB3 thereby exposing hydrophobic regions. Binding assay of rσB3 with cRsbW displayed impaired protein-protein interaction using rσB3-AuNR10 molar ratio of 1:10. The efficacy of AuNR10 was also observed for the biofilm inhibition by S. aureus.

Conclusions

We show how the size and shape of AuNPs modulate the structure/function of rσB3 of S. aureus.

General significance

Because of the involvement of rσB3 in S. aureus pathogenesis, the structural/functional modulation by AuNR10 could be of therapeutic relevance for nanoparticle-based antibacterial strategies.
背景:现代已经见证了纳米颗粒(NPs)的广泛应用,从药物输送到生物医学用途。本文首次报道了不同大小和形状的金纳米颗粒(AuNPs)对引起感染的病原菌金黄色葡萄球菌应激反应蛋白σB的影响。在σB的3个保守结构域中,我们重点研究了与金黄色葡萄球菌抗σ因子RsbW结合的结构域3。方法:研究重组σB3 (rσB3)与三种类型的AuNPs的相互作用;直径分别为10 nm (AuNS10)和100 nm (AuNS100)的球形和棒状(AuNR10)。采用不同的生物物理技术研究了AuNPs对rσB3的结构调节。使用AuNR10进行rσB3-cRsbW结合实验,采用Native-PAGE。结果:等温滴定量热法分别揭示了rσB3-AuNSs和rσB3-AuNR的放热和吸热变化。rσB3的远紫外CD与aur10的摩尔比为1:5和1:10时,α-螺旋含量下降。与4,4′-二苯胺-1,1′-二萘基-5,5′-二磺酸结合后,rσB3- aunr10偶联物的荧光强度增强,表明rσB3展开,从而暴露疏水区域。rσB3与cRsbW的结合实验表明,当rσB3与aunr10的摩尔比为1:10时,rσB3与cRsbW的蛋白相互作用受损。同时观察了aur10对金黄色葡萄球菌生物膜的抑制作用。结论:我们揭示了AuNPs的大小和形状如何调节金黄色葡萄球菌rσB3的结构/功能。一般意义:由于rσB3参与金黄色葡萄球菌的发病机制,AuNR10的结构/功能调节可能与基于纳米颗粒的抗菌策略具有治疗相关性。
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引用次数: 0
Histidine betaine trimethylammonia-lyase, enzyme coupled with terminal urocanate reductase in Shewanella woodyi grown anaerobically 组氨酸甜菜碱三甲氨解酶,木氏希瓦氏菌厌氧生长中与末端尿酸还原酶偶联的酶。
IF 2.2 3区 生物学 Q3 BIOCHEMISTRY & MOLECULAR BIOLOGY Pub Date : 2025-11-12 DOI: 10.1016/j.bbagen.2025.130886
Yulia V. Bertsova, Marina V. Serebryakova, Alexander A. Baykov, Alexander V. Bogachev
Bacteria coping with oxygen deficiency can switch to alternative terminal electron acceptors, which can be normal metabolic intermediates or products of dedicated coupled reactions. In the latter case, the genes for the respective terminal reductase and coupling enzyme are expected to cluster in the genome. Here, we determined the roles of two uncharacterized periplasmic proteins encoded by the swoo_3912swoo_3913 gene cluster in the facultatively anaerobic marine bacterium Shewanella woodyi. We confirmed the current database annotation of the former protein as “urocanate reductase” but identified the latter protein as a histidine betaine trimethylammonia-lyase (HBTL). HBTL converts histidine betaine into urocanate and trimethylamine and is remarkably specific for histidine betaine as substrate. HBTL requires Mg2+ for activity and undergoes slow reversible inactivation at low Mg2+ concentrations. HBTL activity was not evident in S. woodyi cells grown aerobically but was induced in cells grown anaerobically. Both histidine betaine and urocanate supported anaerobic S. woodyi growth and, hence, respiration. Similar gene clusters are found in many anaerobic bacteria, suggesting a wide occurrence of the anaerobic respiration pathway discovered in this work in the bacterial world.
应对缺氧的细菌可以切换到替代的终端电子受体,这可以是正常的代谢中间体或专用偶联反应的产物。在后一种情况下,各自的末端还原酶和偶联酶的基因预计会聚集在基因组中。在这里,我们确定了两个由swoo_3912-swoo_3913基因簇编码的未被鉴定的外质蛋白在兼性厌氧海洋细菌希瓦氏菌中的作用。我们确认了前一种蛋白的数据库注释为“尿糖酸还原酶”,而后一种蛋白为组氨酸甜菜碱三甲胺分解酶(HBTL)。HBTL将组氨酸甜菜碱转化为尿酸盐和三甲胺,并且对组氨酸甜菜碱作为底物具有显著的特异性。HBTL需要Mg2+才能激活,并且在低Mg2+浓度下经历缓慢可逆的失活。HBTL活性在好氧培养的木藻细胞中不明显,但在厌氧培养的细胞中被诱导。组氨酸甜菜碱和尿酸盐都支持厌氧木梭菌生长,因此也支持呼吸作用。在许多厌氧菌中都发现了类似的基因簇,这表明本研究发现的厌氧呼吸途径在细菌世界中广泛存在。
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引用次数: 0
Hepatic response to ethanol feeding in a hepatocyte-specific fatty acid binding protein-4 knock out mouse model 肝细胞特异性脂肪酸结合蛋白-4敲除小鼠模型对乙醇喂养的肝脏反应。
IF 2.2 3区 生物学 Q3 BIOCHEMISTRY & MOLECULAR BIOLOGY Pub Date : 2025-11-11 DOI: 10.1016/j.bbagen.2025.130885
Neha Attal , Trenton A. Pritt , Melissa Stair , Tony E. Reeves , Iain H. McKillop

Background

Early alcohol-dependent liver disease (ALD) is characterized by increased hepatic fat storage (hepatosteatosis). Fatty acid binding protein 4 (FABP4), a protein not normally expressed in liver, becomes highly expressed in ALD. This study developed a hepatocyte-specific FABP4 mouse knockout (HS-Fabp4−/−) to study liver responses to alcohol.

Methods

An HS-Fabp4−/− mouse was created using a Cre/loxP embryonic stem cell approach. Male and female HS-Fabp4−/− and wildtype (WT; C57Bl/6) mice were maintained on ethanol-drinking water (EtOH-DW) for 4-weeks. Liver damage, triglyceride content and pathology were assessed. Hepatic FABP1–9 mRNA and FABP4 and FABP5 protein were measured. Human hepatoma cell proliferation in response to exogenous FABP4 or FABP5 was analyzed.

Results

Hepatocyte-specific FABP4 deletion was confirmed in HS-Fabp4−/− mice. No gross phenotypic differences were observed between HS-Fabp4−/− and WT. Maintenance on EtOH-DW resulted in microsteatosis, increased hepatic triglycerides, and elevated aspartate and alanine transaminases, with no differences detected between pair-matched HS-Fabp4−/− and WT mice. Hepatic FABP1–9 mRNA analysis revealed increased FABP4 and FABP5 mRNA expression in WT mice, and elevated FABP5 mRNA in HS-Fabp4−/− mice in response to EtOH-DW, effects that were mirrored in serum FABP4/5 protein. Exposure of hepatoma cells to FABP4 or FABP5 revealed FABP4, but not FABP5, stimulated cell proliferation.

Conclusions

Hepatocyte-specific FABP4 deletion does not alter hepatic fat accumulation in response to EtOH feeding. Hepatic FABP4 protein produced in response to EtOH is released from hepatocytes and exogenous FABP4 promotes hepatoma cell proliferation in vitro, an effect not observed for FABP5.
背景:早期酒精依赖性肝病(ALD)的特征是肝脏脂肪储存增加(肝骨赘病)。脂肪酸结合蛋白4 (FABP4),一种在肝脏中不正常表达的蛋白,在ALD中变得高表达。本研究开发了肝细胞特异性FABP4小鼠基因敲除(HS-Fabp4-/-)来研究肝脏对酒精的反应。方法:采用Cre/loxP胚胎干细胞法建立HS-Fabp4-/-小鼠。雄性和雌性HS-Fabp4-/-和野生型(WT; C57Bl/6)小鼠在乙醇饮用水(EtOH-DW)中维持4周。评估肝损害、甘油三酯含量及病理。测定肝脏FABP1-9 mRNA和FABP4、FABP5蛋白表达。分析外源性FABP4或FABP5对人肝癌细胞增殖的影响。结果:在HS-Fabp4-/-小鼠中证实肝细胞特异性FABP4缺失。HS-Fabp4-/-和WT之间没有明显的表型差异。维持EtOH-DW导致微脂肪变性、肝脏甘油三酯升高、天冬氨酸和丙氨酸转氨酶升高,配对的HS-Fabp4-/-和WT小鼠之间没有差异。肝脏FABP1-9 mRNA分析显示,在WT小鼠中FABP4和FABP5 mRNA表达升高,在HS-Fabp4-/-小鼠中FABP5 mRNA表达升高,这反映在血清FABP4/5蛋白中。肝癌细胞暴露于FABP4或FABP5后,发现FABP4刺激细胞增殖,而FABP5没有。结论:肝细胞特异性FABP4缺失不会改变EtOH喂养后肝脏脂肪的积累。在体外实验中,外源性FABP4可促进肝癌细胞增殖,而FABP5则未观察到这种作用。
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引用次数: 0
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Biochimica et biophysica acta. General subjects
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