Biophysical chemistry最新文献

{"title":"Phenolic fractions of Heliotropium Bacciferum inhibit human insulin aggregation and protect against amyloid-induced cytotoxicity: Structural and biophysical analysis","authors":"Moneera Saud Al-Bagmi ,&nbsp;Majed S. Alokail ,&nbsp;Nasser M. Al-Daghri ,&nbsp;Nojood Altwaijry ,&nbsp;Ibrahim M. Aziz ,&nbsp;Fahad N. Almajhdi ,&nbsp;Mohd Shahnawaz Khan","doi":"10.1016/j.bpc.2025.107437","DOIUrl":"10.1016/j.bpc.2025.107437","url":null,"abstract":"<div><div>In humans, more than 50 diseases are related to protein fibrillation, including Alzheimer's and Parkinson's diseases. Inhibition of amyloid fibril formation using natural products is one of the main therapeutic strategies for preventing the progression of these diseases. In this context, phenolic extract fractions from <em>Heliotropium bacciferum</em> leaves were evaluated for their ability to inhibit the aggregation of human insulin (HI), an appropriate model protein for fibrillation under physiological conditions and agitation at 600 rpm. Our results exhibited HI fibrillation under studied conditions, with aggregation kinetic fitting a sigmoidal curve with <span><math><msub><mi>t</mi><mi>lag</mi></msub></math></span> and <span><math><msub><mi>k</mi><mi>app</mi></msub></math></span> values of 44.4 h and 0.16 h⁻¹, respectively. Structural changes preceding the onset of fibril formation were detected by 8-Anilino-1-naphthalene-sulphonic acid (ANS) probe, revealed the exposure of hydrophobic regions in the HI peptide to the solvent, with <span><math><msub><mi>t</mi><mi>lag</mi></msub></math></span> and <span><math><msub><mi>k</mi><mi>app</mi></msub></math></span> values of 18.2 h 0.12 h⁻¹, respectively. CD spectroscopy calculated the formed fibrils comprised of 51.6 % β-sheet structure and 43.0 % unordered structure. In vitro studies demonstrated a dose-dependent inhibitory effect of <em>H. bacciferum</em> extracts on HI fibrillation. The free phenolic fraction (FPF) at 200 μg/mL exhibited nearly complete inhibition, whereas the bound phenolic fraction (BPF) demonstrated a 52 % reduction in fibrillation. These findings were further validated using Rayleigh light scattering (RLS) and circular dichroism analyses. Transmission electron microscopy (TEM) validated the formation of insulin fibrillation and its inhibition by extract fractions. Moreover, MTT assay results on SH-SY5Y cells showed that both extract fractions attenuated HI fibril-induced neuronal toxicity in a dose-dependent manner. Furthermore, RT-PCR analysis revealed that co-treatment with a low concentration (7.8 μg/mL) of <em>H. bacciferum</em> extracts led to a significant reduction in the expression levels of pro-apoptotic genes (Casp3 and Bax) and an increase in the anti-apoptotic gene Bcl-2 in SH-SY5Y cells treated with fibrillated HI. This study highlights the potential of <em>H. bacciferum</em> extracts as therapeutic agents against protein fibrillation-related diseases and underscores the importance of polyphenols in preventing amyloid fibril formation.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"322 ","pages":"Article 107437"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143817579","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}

{"title":"A detailed review of genetically encodable RFPs and far-RFPs and their applications in advanced super-resolution imaging techniques","authors":"Jianshu Dong ,&nbsp;Bilal Tayyab ,&nbsp;Jiangyun Wang","doi":"10.1016/j.bpc.2025.107432","DOIUrl":"10.1016/j.bpc.2025.107432","url":null,"abstract":"<div><div>The red fluorescent proteins (RFPs) and far-red fluorescent proteins (far-RFPs) that are encoded genetically can emit fluorescence within the spectral ranges of 580–680 nm when exposed to the light of appropriate wavelengths. Unlike many RFPs derived from coral species, numerous far-RFPs are optimized synthetic constructs engineered from different orange or red-emitting progenitors. Various categories have been established for the available RFPs and far-red fluorescent proteins based on their photo-chemical profile, fluorescence mechanism, and switching kinetics. Fluorescent probes (FPs) derived from these classes are extensively utilized for labelling and visualizing in vivo and in vitro specimens. Traditional optical microscopy methods generate diffraction-limited, indistinct images owing to the restricted resolution capability of light ranging from 200 to 300 nm. Since 2005, super-resolution microscopy has been a topic of great interest due to its ability to achieve imaging at spatial resolutions of less than 100 nm. The 2014 Nobel Prize in Chemistry was awarded to Eric Betzig, Stefan Hell, and William E. Moerner for their contributions to demonstrating the effectiveness of genetically encodable fluorescent proteins in visualizing biological systems through super-resolution fluorescence microscopy. This review provides a concise overview of RFPs and far-RFPs, including the involvement of surrounding residues in chromophore intactness, stability, autocatalytic maturation and switching kinetics. All the chemical pathways proposed for photoactivation, photoconversion and photoswitching mechanisms are concisely reviewed. Subsequently, a comprehensive summary was provided regarding the various types of super-resolution techniques that are commonly employed, elucidating their underlying principles of operation, as well as the potential future applications of RFPs/far-RFPs in the field of biological imaging.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"322 ","pages":"Article 107432"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143673287","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}

{"title":"Autoencoder-based drug-virus association prediction with reliable negative sample selection: A case study with COVID-19","authors":"A.S. Aruna ,&nbsp;K.R. Remesh Babu ,&nbsp;K. Deepthi","doi":"10.1016/j.bpc.2025.107434","DOIUrl":"10.1016/j.bpc.2025.107434","url":null,"abstract":"<div><div>Emergence of viruses cause unprecedented challenges and thus leading to wide-ranging consequences today. The world has faced massive disruptions like COVID-19 and continues to suffer in terms of public health and world economy. Fighting with this emergence of viruses and its reemergence plays a critical role in the health care industry. Identification of novel virus-drug associations is a vital step in drug discovery. Prediction and prioritization of novel virus-drug associations through computational approaches is an alternative and best choice considering the cost and risk of biological experiments. This study proposes a method, KR-AEVDA that relies on k-nearest neighbor based reliable negative sample selection and autoencoder based feature extraction to explore promising virus-drug associations for further experimental validation. The method analyzes complex relationships among drugs and viruses by investigating similarity and association data between drugs and viruses. It generates feature vectors from the similarity data, and reliable negative samples are extracted through an effective distance-based algorithm from the unlabeled samples in the dataset. Then high level features are extracted via an autoencoder and is fed to an ensemble classifier for inferring novel associations. Experimental results on three different datasets showed that KR-AEVDA reliably attained better performance than other state-of-the-art methods. Molecular docking is carried out between the top-predicted drugs and the crystal structure of the SARS-CoV-2's main protease to further validate the predictions. Case studies for SARS-CoV-2 illustrate the effectiveness of KR-AEVDA in identifying potential virus-drug associations.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"322 ","pages":"Article 107434"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143629532","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}

{"title":"Elucidating thyroid hormone transport proteins disruption by nitrophenols through computational and spectroscopic analysis","authors":"Yanhong Zheng,&nbsp;Zeyu Song,&nbsp;Muwei Huang,&nbsp;Cancan Li,&nbsp;Chunke Nong,&nbsp;Tinghao Jiang,&nbsp;Zhanji Li,&nbsp;Zhongsheng Yi","doi":"10.1016/j.bpc.2025.107415","DOIUrl":"10.1016/j.bpc.2025.107415","url":null,"abstract":"<div><div>Thyroxine (T4), as a type of thyroid hormone (TH), is a key hormone in regulating human metabolism, growth and development, central nervous system functions, and energy balance. It relies on TH transport proteins to reach cells and exert its biological actions. However, the binding of nitrophenol pollutants to TH transport proteins prevents the delivery of thyroid hormones to cells, thereby inhibiting the effects of the hormones. This study combines spectroscopic experiments and computational simulations to explore the mechanism of nitrophenols' interference with TH transport proteins. Detailed information on the quenching mechanism, binding parameters, interaction forces, binding models, and conformational changes of nitrophenols (PNP), chlorinated nitrophenols (CNP), and brominated nitrophenols (BNP) with TH transport proteins is obtained through spectroscopic experiments. Nitrophenols are found to form hydrogen bonds with residues Lys15, Arg378, and Arg381, respectively, thereby displacing T4 at the binding site in the TH transport proteins. With an increasing number of halogen atoms, the affinity of halogenated nitrophenols for TH transport proteins intensifies. Computational simulations are used to further understand the binding modes and binding sites, providing molecular-level insights into the binding of NPs in the cavity of TH transport proteins. Theoretical evidence from molecular docking and molecular dynamics (MD) simulations supports the experimental findings.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"320 ","pages":"Article 107415"},"PeriodicalIF":3.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465096","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}

{"title":"Investigating the functional dynamics of glyceraldehyde-3-phosphate dehydrogenase upon ligand binding at the putative allosteric binding sites","authors":"Merve Yuce,&nbsp;Ozge Kurkcuoglu","doi":"10.1016/j.bpc.2025.107420","DOIUrl":"10.1016/j.bpc.2025.107420","url":null,"abstract":"<div><div>The glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an attractive target to combat infection-related diseases as antibiotic resistance poses a global threat. Here, we investigated the functional dynamics of methicillin-resistant <em>S. aureus</em> GAPDH (<em>Sa</em>GAPDH) in apo-form and with ligands bound at two distinct potential allosteric binding sites in its tunnel-like region. AutoDock Vina was used for flexible docking with a library of 2447 FDA-approved drugs. After the interaction analysis and chemical fragment clustering, 5 compounds mutual to both sites were selected and subjected to independent 3 × 500 ns-long molecular dynamics (MD) simulations coupled with Molecular Mechanics Generalized Born Surface Area calculations to estimate their binding free energies. The ligand-protein dynamics pointed to either an increase or a decrease in the solvent accessibility of the co-factor NAD⁺ binding site as compared to apo-dynamics without an apparent change in residue fluctuations. Furthermore, dihedral angles of the co-factor binding site residues, particularly R12 and N316 changed upon ligand binding to the tunnel-like region. Residue network models based on the MD trajectories for each system revealed potential allosteric communication pathways linking putative allosteric binding sites to the co-factor binding sites. Favorable interactions between the ligands and the previously suggested hub residues T49-R53, E204 (S-loop) and/or Y180 seemed to affect the solvent accessibility of the binding sites that can either facilitate or prevent NAD⁺ binding. Dynamic coupling of NAD⁺ binding sites through correlated residue fluctuations was consistent in all investigated systems, revealing how cooperativity between the functional sites can be maintained by <em>Sa</em>GAPDH. All findings suggested hit compounds and the putative allosteric binding sites to change the NAD⁺ binding site dynamics that should be further evaluated by in vitro studies to assess their antibacterial activities.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"320 ","pages":"Article 107420"},"PeriodicalIF":3.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509081","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}

{"title":"Transmembrane clustering of short amyloid peptide fragments: A coarse grained molecular dynamics study","authors":"Aleksandra Drajkowska,&nbsp;Andrzej Molski","doi":"10.1016/j.bpc.2025.107418","DOIUrl":"10.1016/j.bpc.2025.107418","url":null,"abstract":"<div><div>Toxicity of amyloid peptides has been linked to peptide aggregation and interactions with lipid bilayers. In this work we use coarse-grained molecular dynamics simulations to study aggregation and transmembrane clustering of short amyloid peptide fragments, A<em>β</em>(25–35) and A<em>β</em>(29–42), in the presence of dipalmitoylphosphatidylcholine (DPPC) and palmitoylolyoilphosphatidylcholine (POPC) bilayers. First, we explored peptide aggregation starting from free monomers placed at the interface of preformed lipid membranes. At low peptide concentrations, no transmembrane clusters were formed in DPPC or POPC membranes. At high peptide concentration, the longer fragment, A<em>β</em>(29–42), showed strong peptide-peptide interactions that led to spontaneous formation of transmembrane clusters in POPC and DPPC. However, the shorter fragment, A<em>β</em>(25–35), did not form transmembrane clusters within the simulation time in either bilayer. To overcome the free-energy barriers to transmembrane clustering, we changed the simulation protocol and started simulations from random mixtures of peptides, lipids, and solvent. Using this system self-assembly approach, we found that both A<em>β</em>(25–35) and A<em>β</em>(29–42) can form stable transmembrane clusters in DPPC and POPC bilayers. Our study suggests that the cooperative effects induced by a localized increase in peptide density may be a mechanism of membrane disruption by short amyloid peptide fragments.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"320 ","pages":"Article 107418"},"PeriodicalIF":3.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509079","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}

{"title":"Systematic molecular profiling of non-native N6-substitution effects on m6A binding to the YTH domains of human RNA m6A readers in diabetes","authors":"Yuting Li ,&nbsp;Peng Tan ,&nbsp;Qianpan Liu ,&nbsp;Huaixin Sun ,&nbsp;Yue Wang ,&nbsp;Siyi Chen ,&nbsp;Weixin Kong ,&nbsp;Xiaoyi Sun ,&nbsp;Xiang Shao","doi":"10.1016/j.bpc.2025.107417","DOIUrl":"10.1016/j.bpc.2025.107417","url":null,"abstract":"<div><div>The RNA <em>N</em>⁶-adenosine methylation, resulting in <em>N</em>⁶-methyl adenosine (m6A), is one of the most important post-transcriptional modification events in the eukaryotic transcriptome, which is dynamically regulated by methyltransferases (writers), recognition proteins (readers) and demethylases (erasers). Human has five m6A readers namely YTHDC1, YTHDC2, YTHDF1, YTHDF2 and YTHDF3 that specifically recognize and bind to the methylated m6A residue of RNA through their YT521-B homology (YTH) domains, which have been involved in the pathogenesis of diabetes mellitus and its diverse complications such as diabetic nephropathy. Instead of the native <em>N</em>⁶-methylation, we herein attempted to explore the molecular effect of various non-native <em>N</em>⁶-substitutions on adenosine (A) binding behavior to YTH domains. A systematic interaction profile of 40 reported <em>N</em>⁶-substituted adenosine (x6A) mononucleotides with 5 human reader YTH domains was created computationally. Heuristic clustering of the profile divided these YTH domains and these x6A mononucleotides into two subfamilies and three classes, respectively; they represent distinct intrinsic interaction modes between the domains and mononucleotides. Statistical survey unraveled that the volume (<em>V</em>_g) and hydrophobicity (<em>H</em>_g) of <em>N</em>⁶-substituted chemical groups exhibit linear and nonlinear correlations with the binding energy (Δ<em>G</em>_ttl) of x6A mononucleotides to YTH domains, respectively; <em>N</em>⁶-substitutions with moderate size and weak polarity are favorable for the x6A binding. From the profile the <em>N</em>⁶-bromomethyl adenosine (brm6A) was identified as a potent binder of YTHDF2 YTH domain; its affinity was improved significantly by 77.2-fold from A and considerably by 19.5-fold from m6A. Structural modeling observed that the <em>N</em>⁶-bromomethyl group of brm6A is tightly packed against an aromatic cage defined by the Trp432-Trp486-Trp491 triad of YTHDF2 YTH domain. Electron-correlation analysis revealed that the bromine atom can form geometrically and energetically satisfactory halogen-π interactions with the aromatic cage, thus conferring considerable affinity and specificity to the domain–brm6A interaction.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"320 ","pages":"Article 107417"},"PeriodicalIF":3.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465059","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}

{"title":"Effect of ergosterol or cholesterol on the morphology and dynamics of the POPC/sphingomyelin bilayer","authors":"Fernando Favela-Rosales ,&nbsp;Jorge Hernández-Cobos ,&nbsp;Arturo Galván-Hernández ,&nbsp;Omar Hernández-Villanueva ,&nbsp;Iván Ortega-Blake","doi":"10.1016/j.bpc.2025.107408","DOIUrl":"10.1016/j.bpc.2025.107408","url":null,"abstract":"<div><div>Phase segregation and domain formation in cell membranes and model lipid bilayers have become a relevant topic in the last decades due to their role in important cell functions such as signaling and molecule-membrane interactions. To date, the most accepted explanation for the formation of these domains in mammalian cells is that cholesterol-enriched sphingomyelin patches of membrane form because of the preferential interaction between them. However, detailed information on molecular interactions within cholesterol-containing bilayers and their comparison with other sterol-containing bilayers, such as those containing ergosterol, is needed to understand the role these molecules have. Recent experimental findings have shown sterol-dependent differences in the morphology of supported lipid bilayers, but the molecular basis for these differences remains unclear. This work provides a molecular explanation for these differences using atomistic Molecular Dynamics simulations of lipid bilayers composed of 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) and N-palmitoyl-D-erythro-sphingosylphosphorylcholine (PSM) with 20 mol% of cholesterol or ergosterol. Atomic force microscopy was used to validate the simulation. The simulation ran for 11 μs and revealed that both sterols affect the morphology of the membrane. Key findings include: ergosterol induces greater order in PSM domains compared to cholesterol, lipid diffusion constants are lower in ergosterol-containing membranes, sterol flip-flop rates are significantly reduced in ergosterol-containing membranes and ergosterol leads to greater PSM-sterol enrichment. These molecular-level differences provide insight into the experimentally observed variations in domain formation and membrane properties between cholesterol and ergosterol-containing bilayers. Our findings contribute to the understanding of sterol-specific effects on membrane organization and dynamics, with potential implications for cellular processes and drug interactions in different organisms.</div></div><div><h3>Statement of significance</h3><div>This study advances our understanding of how different sterols influence membrane properties through molecular dynamics simulations of three-component lipid membranes. Specifically, we investigate the effects of two major sterols: ergosterol, predominantly found in plants and fungi, and cholesterol, characteristic of mammalian cells. While extensive research has elucidated cholesterol's impact on lipid bilayers, studies on ergosterol's effects are comparatively limited. Our work provides a comprehensive comparison of these sterols, highlighting their similarities and differences. These insights not only enhance our knowledge of cell membrane structure and function, but also contribute to our understanding of selective drug permeability across membranes. This research has potential implications for both fundamental cell biology and pharmaceutical applications.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"320 ","pages":"Article 107408"},"PeriodicalIF":3.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444897","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}

{"title":"Targeting human prostaglandin reductase 1 with Licochalcone A: Insights from molecular dynamics and covalent docking studies","authors":"Sara Abigail Ramírez-Cortés ,&nbsp;Adrián Durán-Vargas ,&nbsp;Jesús Antonio Rauda-Ceja ,&nbsp;Paola Mendoza-Espinosa ,&nbsp;Luis Fernando Cofas-Vargas ,&nbsp;Armando Cruz-Rangel ,&nbsp;Julio Isael Pérez-Carreón ,&nbsp;Enrique García-Hernández","doi":"10.1016/j.bpc.2025.107410","DOIUrl":"10.1016/j.bpc.2025.107410","url":null,"abstract":"<div><div>Prostaglandin reductase 1 (PTGR1) is an NADPH-dependent enzyme critical to eicosanoid metabolism. Its elevated expression in malignant tumors often correlates with poor prognosis due to its role in protecting cells against reactive oxygen species. This study explores the inhibitory potential of licochalcone A, a flavonoid derived from Xinjiang licorice root, on human PTGR1. Using molecular dynamics simulations, we mapped the enzyme's conformational landscape, revealing a low-energy, rigid-body-like movement of the catalytic domain relative to the nucleotide-binding domain that governs PTGR1's transition between open and closed states. Simulations of NADPH-depleted dimer and NADPH-bound monomer highlighted the critical role of intersubunit interactions and coenzyme binding in defining PTGR1's conformational landscape, offering a deeper understanding of its functional adaptability as a holo-homodimer. Covalent docking, informed by prior chemoproteomic cross-linking data, revealed a highly favorable binding pose for licochalcone A at the NADPH-binding site. This pose aligned with a transient noncovalent binding pose inferred from solvent site-guided molecular docking, emphasizing the stereochemical complementarity of the coenzyme-binding site to licochalcone A. Sequence analysis across PTGR1 orthologs in vertebrates and exploration of 3D structures of human NADPH-binding proteins further underscore the potential of the coenzyme-binding site as a scaffold for developing PTGR1-specific inhibitors, positioning licochalcone A as a promising lead compound.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"320 ","pages":"Article 107410"},"PeriodicalIF":3.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the thermal and chemical stability of DNAJB6b and its globular domains","authors":"Celia Fricke ,&nbsp;Jelica Milošević ,&nbsp;Andreas Carlsson ,&nbsp;Lars Boyens-Thiele ,&nbsp;Marija Dubackic ,&nbsp;Ulf Olsson ,&nbsp;Alexander K. Buell ,&nbsp;Sara Linse","doi":"10.1016/j.bpc.2025.107401","DOIUrl":"10.1016/j.bpc.2025.107401","url":null,"abstract":"<div><div>The chaperone DNAJB6b (JB6) plays important roles in increasing amyloid protein solubility and inhibiting amyloid fibril formation, a causative factor for neurodegenerative diseases like Alzheimer's and Parkinson's disease. Insights into the biophysical properties of JB6, including its structure, self-assembly and stability towards denaturation, may enhance the understanding of the physicochemical basis of chaperone action. However, many of the biophysical properties of the chaperone remain elusive. Here, we investigated the structure and stability of JB6 and its domains towards thermal and chemical denaturation using Fourier transform infrared and circular dichroism spectroscopy to examine the thermodynamic properties. Both domains act as independent folding units. We find that the N-terminal domain (NTD) of JB6 is more stable than its C-terminal domain (CTD). Both domains are stabilized in the context of the full-length protein. The intact protein unfolds in a step-wise manner when subjected to a denaturing agent with the CTD unfolding at a lower denaturant concentration than the NTD. The combination of thermal and chemical denaturation followed by differential scanning fluorimetry revealed the enthalpy changes (22.6 and 26.4 kJ mol⁻¹) and heat capacity changes (2.8 and 3.0 kJ/(mol*K)) upon denaturation of NTD alone and of NTD within the full-length protein, respectively. The understanding of JB6's biophysical properties complements the increasing amount of data on JB6's interactions with client proteins, paving the way for further investigation of the mechanism of its cellular function.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"320 ","pages":"Article 107401"},"PeriodicalIF":3.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}