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On the production of singlet oxygen by the isoalloxazine ring in free and protein-bound flavin cofactors 异咯嗪环在自由和蛋白质结合的黄素辅因子中产生单线态氧
IF 3.3 3区 生物学
Biophysical chemistry Pub Date : 2024-10-10 DOI: 10.1016/j.bpc.2024.107333
Andrej Hovan , Michal Gala , Dagmar Sedláková , Gregor Bánó , One-Sun Lee , Gabriel Žoldák , Erik Sedlák
{"title":"On the production of singlet oxygen by the isoalloxazine ring in free and protein-bound flavin cofactors","authors":"Andrej Hovan ,&nbsp;Michal Gala ,&nbsp;Dagmar Sedláková ,&nbsp;Gregor Bánó ,&nbsp;One-Sun Lee ,&nbsp;Gabriel Žoldák ,&nbsp;Erik Sedlák","doi":"10.1016/j.bpc.2024.107333","DOIUrl":"10.1016/j.bpc.2024.107333","url":null,"abstract":"<div><div>Flavin cofactors, flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), as a part of flavoenzymes play a critical role in the catalysis of multiple reactions predominantly of a redox nature. Question arises why nature developed two very similar cofactors with an identical functional part – isoalloxazine ring. We believe that an answer is related to the fact that the isoalloxazine ring belongs to endogenous photosensitizers able to produce reactive and potentially harmful singlet oxygen, <sup>1</sup>O<sub>2</sub>, with high efficiency, Φ<sub>Δ,FMN</sub> ∼ 0.6. In fact, in contrast with one main conformation of FMN in water, the presence of the adenosine mononucleotide in FAD induces a dynamic equilibrium of two main conformations – closed (∼80 %) and open (∼20 %). The presence of predominant closed conformation of FAD in water has a significant impact on the Φ<sub>Δ,FAD</sub> value, which is nearly 10-fold lower, Φ<sub>Δ,FAD</sub> ∼ 0.07, than that of FMN. On the other hand, based on our analysis of a non-homologous dataset of FAD containing 105 proteins, ∼75 % enzyme-bound FAD exists predominantly in open conformations but the Φ<sub>Δ</sub> values are significantly decreased, Φ<sub>Δ</sub> &lt; 0.03. We addressed these contradictory observations by analysis of: (i) dependence of Φ<sub>Δ,FAD</sub> value on opening the FAD conformation by urea and (ii) amino acid propensities for isoalloxazine binding site. We demonstrated that urea-induced destabilization, in 7 M vs 0 M urea, of the closed FAD conformation leads to a ∼ 3-fold increase of Φ<sub>Δ</sub>, proving the causative relation between Φ<sub>Δ</sub> value and the flavin cofactor conformation. Detailed examination of the flavoproteins dataset clearly indicated positive propensities of three amino acids: glycine, cysteine, and tryptophan for isoalloxazine ring binding site. We hypothesize that both the closed conformation of free FAD and the arrangement of the isoalloxazine binding site is important for prevention of potentially harmful <sup>1</sup>O<sub>2</sub> production in cells.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"316 ","pages":"Article 107333"},"PeriodicalIF":3.3,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142436535","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
Stability and conformation of DNA-hairpin in cylindrical confinement DNA 发夹在圆柱约束下的稳定性和构象。
IF 3.3 3区 生物学
Biophysical chemistry Pub Date : 2024-09-30 DOI: 10.1016/j.bpc.2024.107331
Anurag Upadhyaya , Subhadeep Dasgupta , Sanjay Kumar , Prabal K. Maiti
{"title":"Stability and conformation of DNA-hairpin in cylindrical confinement","authors":"Anurag Upadhyaya ,&nbsp;Subhadeep Dasgupta ,&nbsp;Sanjay Kumar ,&nbsp;Prabal K. Maiti","doi":"10.1016/j.bpc.2024.107331","DOIUrl":"10.1016/j.bpc.2024.107331","url":null,"abstract":"<div><div>We conducted atomistic Molecular Dynamics (MD) simulations of DNA-Hairpin molecules encapsulated within Single-Walled Carbon Nanotubes (SWCNTs) at a temperature of 300 K. Our investigation revealed that the structural integrity of the DNA-Hairpin can be maintained within SWCNTs, provided that the diameter of the SWCNT exceeds a critical threshold value. Conversely, when the SWCNT diameter falls below this critical threshold, the DNA-Hairpin undergoes denaturation, even at a temperature of 300 K. The DNA-Hairpin model we employed consisted of a 12-base pair stem and a 3-base loop, and we studied various SWCNTs with different diameters. Our analyses identified a critical SWCNT diameter of 3.39 nm at 300 K. Examination of key structural features, such as hydrogen bonds (H-bonds), van der Waals (vdW) interactions, and other inter-base interactions, demonstrated a significant reduction in the number of H-bonds, vdW energy, and electrostatic energies among the DNA hairpin's constituent bases when confined within narrower SWCNTs (with diameters of 2.84 nm and 3.25 nm). However, it was observed that the increased interaction energy between the DNA-Hairpin and the inner surface of narrower SWCNTs promoted the denaturation of the DNA-Hairpin. In-depth analysis of electrostatic mapping and hydration status further revealed that the DNA-Hairpin experienced inadequate hydration and non-uniform distribution of counter ions within SWCNTs having diameters below the critical value of 3.39 nm. Our inference is that the inappropriate hydration of counter ions, along with their non-uniform spatial distribution around the DNA hairpin, contributes to the denaturation of the molecule within SWCNTs of smaller diameters. For DNA-Hairpin molecules that remained undenatured within SWCNTs, we investigated their mechanical properties, particularly the elastic properties. Our findings demonstrated an increase in the persistence length of the DNA-Hairpin with increasing SWCNT diameter. Additionally, the stretch modulus and torsional stiffness of the DNA-Hairpin were observed to increase as a function of SWCNT diameter, indicating that confinement within SWCNTs enhances the mechanical flexibility of the DNA-Hairpin.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"316 ","pages":"Article 107331"},"PeriodicalIF":3.3,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142457279","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
Characterization of PARP1 binding to c-KIT1 G-quadruplex DNA: Insights into domain-specific interactions PARP1 与 c-KIT1 G-quadruplex DNA 结合的特征:洞察特定结构域的相互作用。
IF 3.3 3区 生物学
Biophysical chemistry Pub Date : 2024-09-25 DOI: 10.1016/j.bpc.2024.107330
Dagur Hanuman Singh , Waghela Deeksha , Eerappa Rajakumara
{"title":"Characterization of PARP1 binding to c-KIT1 G-quadruplex DNA: Insights into domain-specific interactions","authors":"Dagur Hanuman Singh ,&nbsp;Waghela Deeksha ,&nbsp;Eerappa Rajakumara","doi":"10.1016/j.bpc.2024.107330","DOIUrl":"10.1016/j.bpc.2024.107330","url":null,"abstract":"<div><div>Poly(ADP-ribose) polymerase 1 (PARP1) is a nuclear enzyme involved in catalyzing Poly-(ADP-ribosyl)ation. PARP1 binds to different forms of DNA and DNA breaks and thus plays important roles in several cellular processes, including DNA damage repair, cell cycle regulation, chromatin remodeling, and maintaining genomic stability. In this study, we conducted biochemical and biophysical characterization of PARP1 binding to G-quadruplex DNA (G4-DNA). Our investigation identified ZnF1, ZnF3, and WGR as the critical domains to mediate PARP1 binding to G4-c-KIT1. Also, our results show that these domains together show cooperativity for G4-c-KIT1 recognition. Further, we establish that the presence of an oxidized (5-carboxylcytosine) base in the loop region of G4-c-KIT1 (G4-5caC-cKIT1) does not affect its recognition by PARP1. Both G4-c-KIT1 and G4-5caC-cKIT1 are potent stimulators of PARP1's catalytic activity. Our study advances the understanding of PARP1's versatile DNA binding capabilities for G4-c-KIT1 DNA irrespective of the oxidation/ modification in the DNA base. These insights into PARP1's domain-specific contributions to G4-c-KIT1 DNA recognition and catalysis expand our knowledge of its multifaceted roles in DNA repair and genome maintenance.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"315 ","pages":"Article 107330"},"PeriodicalIF":3.3,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142341033","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
Structural changes of Natronomonas pharaonis halorhodopsin in its late photocycle revealed by solid-state NMR spectroscopy 固态核磁共振光谱揭示 Natronomonas pharaonis halorhodopsin 在光周期后期的结构变化。
IF 3.3 3区 生物学
Biophysical chemistry Pub Date : 2024-09-24 DOI: 10.1016/j.bpc.2024.107329
Xin Zhang , Hajime Tamaki , Takashi Kikukawa , Toshimichi Fujiwara , Yoh Matsuki
{"title":"Structural changes of Natronomonas pharaonis halorhodopsin in its late photocycle revealed by solid-state NMR spectroscopy","authors":"Xin Zhang ,&nbsp;Hajime Tamaki ,&nbsp;Takashi Kikukawa ,&nbsp;Toshimichi Fujiwara ,&nbsp;Yoh Matsuki","doi":"10.1016/j.bpc.2024.107329","DOIUrl":"10.1016/j.bpc.2024.107329","url":null,"abstract":"<div><div><em>Natronomonas pharaonis</em> halorhodopsin (<em>Np</em>HR) is a light-driven Cl<sup>−</sup> inward pump that is widely used as an optogenetic tool. Although <em>Np</em>HR is previously extensively studied, its Cl<sup>−</sup> uptake process is not well understood from the protein structure perspective, mainly because in crystalline lattice, it has been difficult to analyze the structural changes associated with the Cl<sup>−</sup> uptake process. In this study, we used solid-state NMR to analyze <em>Np</em>HR both in the Cl<sup>−</sup>-bound and -free states under near-physiological transmembrane condition. Chemical shift perturbation analysis suggested that while the structural change caused by the Cl<sup>−</sup> depletion is widespread over the <em>Np</em>HR molecule, residues in the extracellular (EC) part of helix D exhibited significant conformational changes that may be related to the Cl<sup>−</sup> uptake process. By combining photochemical analysis and dynamic nuclear polarization (DNP)-enhanced solid-state NMR measurement on <em>Np</em>HR point mutants for the suggested residues, we confirmed their importance in the Cl<sup>−</sup> uptake process. In particular, we found the mutation at Ala165 position, located at the trimer interface, to an amino acid with bulky sidechain (A165V) significantly perturbs the late photocycle and disrupts its trimeric assembly in the Cl<sup>−</sup>-free state as well as during the ion-pumping cycle under the photo-irradiated condition. This strongly suggested an outward movement of helix D at EC part, disrupting the trimer integrity. Together with the spectroscopic data and known <em>Np</em>HR crystal structures, we proposed a model that this helix movement is required for creating the Cl<sup>−</sup> entrance path on the extracellular surface of the protein and is crucial to the Cl<sup>−</sup> uptake process.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"315 ","pages":"Article 107329"},"PeriodicalIF":3.3,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142380057","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}
引用次数: 0
Enhancing solution structural analysis of large molecular proteins through optimal stereo array isotope labeling of aromatic amino acids 通过优化芳香族氨基酸的立体阵列同位素标记,加强大分子蛋白质的溶液结构分析
IF 3.3 3区 生物学
Biophysical chemistry Pub Date : 2024-09-18 DOI: 10.1016/j.bpc.2024.107328
Yohei Miyanoiri , Mitsuhiro Takeda , Kosuke Okuma , Tsutomu Terauchi , Masatsune Kainosho
{"title":"Enhancing solution structural analysis of large molecular proteins through optimal stereo array isotope labeling of aromatic amino acids","authors":"Yohei Miyanoiri ,&nbsp;Mitsuhiro Takeda ,&nbsp;Kosuke Okuma ,&nbsp;Tsutomu Terauchi ,&nbsp;Masatsune Kainosho","doi":"10.1016/j.bpc.2024.107328","DOIUrl":"10.1016/j.bpc.2024.107328","url":null,"abstract":"<div><div>The observation of side-chain peaks of aromatic amino acids is the prerequisite for a high-resolution three-dimensional structure determination of proteins by NMR. However, it becomes difficult with increasing molecular size due to an increased transverse relaxation and the control of the relaxation pathway is needed to achieve the observation. We demonstrated that even for the large molecular size of 82 kDa Malate synthase G (MSG), the aromatic <sup>13</sup>C-<sup>1</sup>H (CH) peaks of Tryptophan (Trp) and Phenylalanine (Phe) residues can be observed with high quality using a systematic stable isotope labeling scheme, Stereo-Array Isotope Labeling (SAIL) method. However, the sequence specific assignments of these peaks relied on the use of amino acid substitutions, employing an inefficient method that required many isotopes labeled samples. In this study, we developed novel SAIL amino acids that allow for the observation of the aromatic ring <em>δ</em>,ζ and the aliphatic β position peak of Phe residues. The application of TROSY-based experiment to the isolated CH moieties resulted in the successful observation of discernible and resolved CH peaks in Phe residues in MSG. In MSG, the sequence-specific assignments of the backbone and C<sub>β</sub> positions have already been confirmed. Therefore, using this labeling method, the <em>δ</em> and β position peaks of Phe residues can be clearly assigned in a sequence-specific and stereospecific manner through experiments based on intra-residue NOE. Furthermore, the NOESY experiment also allows for the acquisition of information pertaining to the conformation of Phe residues, such as the χ1 dihedral angle, providing valuable insights for the determination of accurate protein structures and in dynamic analysis. This new SAIL amino acids open an avenue to achieve a variety of NMR analysis of large molecular proteins, including a high-resolution structure determination and dynamics and interaction analysis.</div></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"315 ","pages":"Article 107328"},"PeriodicalIF":3.3,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322988","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}
引用次数: 0
Amyloid-Driven Allostery 淀粉样蛋白驱动的异构体
IF 3.3 3区 生物学
Biophysical chemistry Pub Date : 2024-08-30 DOI: 10.1016/j.bpc.2024.107320
Jaskiran Garcha , Jinfeng Huang , Karla Martinez Pomier , Giuseppe Melacini
{"title":"Amyloid-Driven Allostery","authors":"Jaskiran Garcha ,&nbsp;Jinfeng Huang ,&nbsp;Karla Martinez Pomier ,&nbsp;Giuseppe Melacini","doi":"10.1016/j.bpc.2024.107320","DOIUrl":"10.1016/j.bpc.2024.107320","url":null,"abstract":"<div><p>The fields of allostery and amyloid-related pathologies, such as Parkinson's disease (PD), have been extensively explored individually, but less is known about how amyloids control allostery. Recent advancements have revealed that amyloids can drive allosteric effects in both intrinsically disordered proteins, such as alpha-synuclein (αS), and multi-domain signaling proteins, such as protein kinase A (PKA). Amyloid-driven allostery plays a central role in explaining the mechanisms of gain-of-pathological-function mutations in αS (<em>e.g.</em> E46K, which causes early PD onset) and loss-of-physiological-function mutations in PKA (<em>e.g.</em> A211D, which predisposes to tumors). This review highlights allosteric effects of disease-related mutations and how they can cause exposure of amyloidogenic regions, leading to amyloids that are either toxic or cause aberrant signaling. We also discuss multiple potential modulators of these allosteric effects, such as MgATP and kinase substrates, opening future opportunities to improve current pharmacological interventions against αS and PKA-related pathologies. Overall, we show that amyloid-driven allosteric models are useful to explain the mechanisms underlying disease-related mutations.</p></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"315 ","pages":"Article 107320"},"PeriodicalIF":3.3,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0301462224001492/pdfft?md5=c319c38dccfaf54f6b0a161dbb4db39f&pid=1-s2.0-S0301462224001492-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142228708","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}
引用次数: 0
Biophysical characterization of hydrogen sulfide: A fundamental exploration in understanding significance in cell signaling 硫化氢的生物物理特征:了解细胞信号传递意义的基础性探索
IF 3.3 3区 生物学
Biophysical chemistry Pub Date : 2024-08-30 DOI: 10.1016/j.bpc.2024.107317
Tejasvi Pandey , Rajinder Singh Kaundal , Vivek Pandey
{"title":"Biophysical characterization of hydrogen sulfide: A fundamental exploration in understanding significance in cell signaling","authors":"Tejasvi Pandey ,&nbsp;Rajinder Singh Kaundal ,&nbsp;Vivek Pandey","doi":"10.1016/j.bpc.2024.107317","DOIUrl":"10.1016/j.bpc.2024.107317","url":null,"abstract":"<div><p>Hydrogen sulfide (H₂S) has emerged as a significant signaling molecule involved in various physiological processes, including vasodilation, neurotransmission, and cytoprotection. Its interactions with biomolecules are critical to understand its roles in health and disease. Recent advances in biophysical characterization techniques have shed light on the complex interactions of H₂S with proteins, nucleic acids, and lipids. Proteins are primary targets for H₂S, which can modify cysteine residues through S-sulfhydration, impacting protein function and signaling pathways. Advanced spectroscopic techniques, such as mass spectrometry and NMR, have enabled the identification of specific sulfhydrated sites and provided insights into the structural and functional consequences of these modifications. Nucleic acids also interact with H₂S, although this area is less explored compared to proteins. Recent studies have demonstrated that H₂S can induce modifications in nucleic acids, affecting gene expression and stability. Techniques like gel electrophoresis and fluorescence spectroscopy have been utilized to investigate these interactions, revealing that H₂S can protect DNA from oxidative damage and modulate RNA stability and function. Lipids, being integral components of cell membranes, interact with H₂S, influencing membrane fluidity and signaling. Biophysical techniques such as electron paramagnetic resonance (EPR) and fluorescence microscopy have elucidated the effects of H₂S on lipid membranes. These studies have shown that H₂S can alter lipid packing and dynamics, which may impact membrane-associated signaling pathways and cellular responses to stress. In the current work we have integrated this with key scientific explainations to provide a comprehensive review.</p></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"314 ","pages":"Article 107317"},"PeriodicalIF":3.3,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142136439","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
Simulating the anti-aggregative effect of fasudil in early dimerisation process of α-synuclein 模拟法舒地尔在α-突触核蛋白早期二聚化过程中的抗聚集作用
IF 3.3 3区 生物学
Biophysical chemistry Pub Date : 2024-08-30 DOI: 10.1016/j.bpc.2024.107319
Sneha Menon, Jagannath Mondal
{"title":"Simulating the anti-aggregative effect of fasudil in early dimerisation process of α-synuclein","authors":"Sneha Menon,&nbsp;Jagannath Mondal","doi":"10.1016/j.bpc.2024.107319","DOIUrl":"10.1016/j.bpc.2024.107319","url":null,"abstract":"<div><p>The aggregation of the protein α-synuclein into amyloid deposits is associated with multiple neurological disorders, including Parkinson's disease. Soluble amyloid oligomers are reported to exhibit higher toxicity than insoluble amyloid fibrils, with dimers being the smallest toxic oligomer. Small molecule drugs, such as fasudil, have shown potential in targeting α-synuclein aggregation and reducing its toxicity. In this study, we use atomistic molecular dynamics simulations to demonstrate how fasudil affects the earliest stage of aggregation, namely dimerization. Our results show that the presence of fasudil reduces the propensity for intermolecular contact formation between protein chains. Consistent with previous reports, our analysis confirms that fasudil predominantly interacts with the negatively charged C-terminal region of α-synuclein. However, we also observe transient interactions with residues in the charged N-terminal and hydrophobic NAC regions. Our simulations indicate that while fasudil prominently interacts with the C-terminal region, it is the transient interactions with residues in the N-terminal and NAC regions that effectively block the formation of intermolecular contacts between protein chains and prevent early dimerization of this disordered protein.</p></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"314 ","pages":"Article 107319"},"PeriodicalIF":3.3,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142129222","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
Secondary structure propensities of the Ebola delta peptide E40 in solution and model membrane environments 埃博拉δ肽 E40 在溶液和模型膜环境中的二级结构倾向性
IF 3.3 3区 生物学
Biophysical chemistry Pub Date : 2024-08-28 DOI: 10.1016/j.bpc.2024.107318
Jiayu Li , David A. Eagles , Isaac J. Tucker , Anneka C. Pereira Schmidt , Evelyne Deplazes
{"title":"Secondary structure propensities of the Ebola delta peptide E40 in solution and model membrane environments","authors":"Jiayu Li ,&nbsp;David A. Eagles ,&nbsp;Isaac J. Tucker ,&nbsp;Anneka C. Pereira Schmidt ,&nbsp;Evelyne Deplazes","doi":"10.1016/j.bpc.2024.107318","DOIUrl":"10.1016/j.bpc.2024.107318","url":null,"abstract":"<div><p>The Ebola delta peptide is an amphipathic, 40-residue peptide encoded by the Ebola virus, referred to as E40. The membrane-permeabilising activity of the E40 delta peptide has been demonstrated in cells and lipid vesicles suggesting the E40 delta peptide likely acts as a viroporin. The lytic activity of the peptide increases in the presence of anionic lipids and a disulphide bond in the C-terminal part of the peptide. Previous in silico work predicts the peptide to show a partially helical structure, but there is no experimental information on the structure of E40. Here, we use circular dichroism spectroscopy to report the secondary structure propensities of the reduced and oxidised forms of the E40 peptide in water, detergent micelles, and lipid vesicles composed of neutral and anionic lipids (POPC and POPG, respectively). Results indicate that the peptide is predominately a random coil in solution, and the disulphide bond has a small but measurable effect on peptide conformation. Secondary structure analysis shows large uncertainties and dependence on the reference data set and, in our system, cannot be used to accurately determine the secondary structure motifs of the peptide in membrane environments. Nevertheless, the spectra can be used to assess the relative changes in secondary structure propensities of the peptide depending on the solvent environment and disulphide bond. In POPC-POPG vesicles, the peptide transitions from a random coil towards a more structured conformation, which is even more pronounced in negatively charged SDS micelles. In vesicles, the effect depends on the peptide-lipid ratio, likely resulting from vesicle surface saturation. Further experiments with zwitterionic POPC vesicles and DPC micelles show that both curvature and negatively charged lipids can induce a change in conformation, with the two effects being cumulative. Electrostatic screening from Na<sup>+</sup> ions reduced this effect. The oxidised form of the peptide shows a slightly lower propensity for secondary structure and retains a more random coil conformation even in the presence of PG-PC vesicles.</p></div>","PeriodicalId":8979,"journal":{"name":"Biophysical chemistry","volume":"314 ","pages":"Article 107318"},"PeriodicalIF":3.3,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142121951","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
Effects of sodium dodecyl sulfate, Sarkosyl and sodium lauroyl glutamate on the structure of proteins monitored by agarose native gel electrophoresis and circular dichroism 十二烷基硫酸钠、Sarkosyl 和月桂酰谷氨酸钠对琼脂糖原生凝胶电泳和圆二色性监测蛋白质结构的影响
IF 3.3 3区 生物学
Biophysical chemistry Pub Date : 2024-08-14 DOI: 10.1016/j.bpc.2024.107316
Teruo Akuta , Tomoto Ura , Takeshi Oikawa , Yui Tomioka , Akiko Eguchi , Tsutomu Arakawa
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