1
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Rao YF, Sun LZ, Luo MB. Na +-Mg 2+ ion effects on conformation and translocation dynamics of single-stranded RNA: Cooperation and competition. Int J Biol Macromol 2024; 267:131273. [PMID: 38569994 DOI: 10.1016/j.ijbiomac.2024.131273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 03/20/2024] [Accepted: 03/28/2024] [Indexed: 04/05/2024]
Abstract
The nanopore-based translocation of a single-stranded RNA (ssRNA) in mixed salt solution has garnered increasing interest for its biological and technological significance. However, it is challenging to comprehensively understand the effects of the mixed ion species on the translocation dynamics due to their cooperation and competition, which can be directly reflected by the ion screening and neutralizing effects, respectively. In this study, Langevin dynamics simulation is employed to investigate the properties of ssRNA conformation and translocation in mixed Na+-Mg2+ ion environments. Simulation results reveal that the ion screening effect dominates the change in the ssRNA conformational size, the ion neutralizing effect controls the capture rate of the ssRNA by the nanopore, and both of them take charge of the different changes in translocation time of the ssRNA under various mixed ion environments. Under high Na+ ion concentration, as Mg2+ concentration increases, the ion neutralizing effect strengthens, weakening the driving force inside the nanopore, leading to longer translocation time. Conversely, at low Na+ concentration, an increase in Mg2+ concentration enhances the ion screening effect, aiding in faster translocation. Furthermore, these simulation results will be explained by quantitative analysis, advancing a deeper understanding of the complicated effects of the mixed Na+-Mg2+ ions.
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Affiliation(s)
- Yi-Fan Rao
- School of Physics, Zhejiang University, Hangzhou 310027, China; Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, China
| | - Li-Zhen Sun
- Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, China.
| | - Meng-Bo Luo
- School of Physics, Zhejiang University, Hangzhou 310027, China.
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2
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Sinzger-D'Angelo M, Hanst M, Reinhardt F, Koeppl H. Effects of mRNA conformational switching on translational noise in gene circuits. J Chem Phys 2024; 160:134108. [PMID: 38573847 DOI: 10.1063/5.0186927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 03/08/2024] [Indexed: 04/06/2024] Open
Abstract
Intragenic translational heterogeneity describes the variation in translation at the level of transcripts for an individual gene. A factor that contributes to this source of variation is the mRNA structure. Both the composition of the thermodynamic ensemble, i.e., the stationary distribution of mRNA structures, and the switching dynamics between those play a role. The effect of the switching dynamics on intragenic translational heterogeneity remains poorly understood. We present a stochastic translation model that accounts for mRNA structure switching and is derived from a Markov model via approximate stochastic filtering. We assess the approximation on various timescales and provide a method to quantify how mRNA structure dynamics contributes to translational heterogeneity. With our approach, we allow quantitative information on mRNA switching from biophysical experiments or coarse-grain molecular dynamics simulations of mRNA structures to be included in gene regulatory chemical reaction network models without an increase in the number of species. Thereby, our model bridges a gap between mRNA structure kinetics and gene expression models, which we hope will further improve our understanding of gene regulatory networks and facilitate genetic circuit design.
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Affiliation(s)
| | - Maleen Hanst
- Centre for Synthetic Biology, Technische Universität Darmstadt, Darmstadt, Germany
| | - Felix Reinhardt
- Centre for Synthetic Biology, Technische Universität Darmstadt, Darmstadt, Germany
| | - Heinz Koeppl
- Centre for Synthetic Biology, Technische Universität Darmstadt, Darmstadt, Germany
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3
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Kawamukai H, Takishita S, Shimizu K, Kohda D, Ishimori K, Saio T. Conformational Distribution of a Multidomain Protein Measured by Single-Pair Small-Angle X-ray Scattering. J Phys Chem Lett 2024; 15:744-750. [PMID: 38221741 PMCID: PMC10823528 DOI: 10.1021/acs.jpclett.3c02600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 01/16/2024]
Abstract
The difficulty in evaluating the conformational distribution of proteins in solution often hinders mechanistic insights. One possible strategy for visualizing conformational distribution is distance distribution measurement by single-pair small-angle X-ray scattering (SAXS), in which the scattering interference from only a specific pair of atoms in the target molecule is extracted. Despite this promising concept, with few applications in synthetic small molecules and DNA, technical difficulties have prevented its application in protein conformational studies. This study used a synthetic tag to fix the lanthanide ion at desired sites on the protein and used single-pair SAXS with contrast matching to evaluate the conformational distribution of the multidomain protein enzyme MurD. These data highlighted the broad conformational and ligand-driven distribution shifts of MurD in solution. This study proposes an important strategy in solution structural biology that targets dynamic proteins, including multidomain and intrinsically disordered proteins.
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Affiliation(s)
- Honoka Kawamukai
- Graduate
School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan
- Graduate
School of Medical Sciences, Tokushima University, Tokushima 770-8503, Japan
| | - Shumpei Takishita
- Graduate
School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Kazumi Shimizu
- Faculty
of Education and Integrated Arts and Sciences, Waseda University, Tokyo 169-8050, Japan
| | - Daisuke Kohda
- Division
of Structural Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Koichiro Ishimori
- Graduate
School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan
- Department
of Chemistry, Faculty of Science, Hokkaido
University, Sapporo 060-0810, Japan
| | - Tomohide Saio
- Graduate
School of Medical Sciences, Tokushima University, Tokushima 770-8503, Japan
- Institute
of Advanced Medical Sciences, Tokushima
University, Tokushima 770-8503, Japan
- Fujii
Memorial Institute of Medical Sciences, Institute of Advanced Medical
Sciences, Tokushima University, Tokushima 770-8503, Japan
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4
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Wang X, Yu S, Lou E, Tan YL, Tan ZJ. RNA 3D Structure Prediction: Progress and Perspective. Molecules 2023; 28:5532. [PMID: 37513407 PMCID: PMC10386116 DOI: 10.3390/molecules28145532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/05/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Ribonucleic acid (RNA) molecules play vital roles in numerous important biological functions such as catalysis and gene regulation. The functions of RNAs are strongly coupled to their structures or proper structure changes, and RNA structure prediction has been paid much attention in the last two decades. Some computational models have been developed to predict RNA three-dimensional (3D) structures in silico, and these models are generally composed of predicting RNA 3D structure ensemble, evaluating near-native RNAs from the structure ensemble, and refining the identified RNAs. In this review, we will make a comprehensive overview of the recent advances in RNA 3D structure modeling, including structure ensemble prediction, evaluation, and refinement. Finally, we will emphasize some insights and perspectives in modeling RNA 3D structures.
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Affiliation(s)
- Xunxun Wang
- Department of Physics, Key Laboratory of Artificial Micro & Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Shixiong Yu
- Department of Physics, Key Laboratory of Artificial Micro & Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - En Lou
- Department of Physics, Key Laboratory of Artificial Micro & Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Ya-Lan Tan
- School of Bioengineering and Health, Wuhan Textile University, Wuhan 430200, China
- Research Center of Nonlinear Science, School of Mathematical and Physical Sciences, Wuhan Textile University, Wuhan 430200, China
| | - Zhi-Jie Tan
- Department of Physics, Key Laboratory of Artificial Micro & Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
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5
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Murty R, Bera MK, Walton IM, Whetzel C, Prausnitz MR, Walton KS. Interrogating Encapsulated Protein Structure within Metal-Organic Frameworks at Elevated Temperature. J Am Chem Soc 2023; 145:7323-7330. [PMID: 36961883 PMCID: PMC10080685 DOI: 10.1021/jacs.2c13525] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2023]
Abstract
Encapsulating biomacromolecules within metal-organic frameworks (MOFs) can confer thermostability to entrapped guests. It has been hypothesized that the confinement of guest molecules within a rigid MOF scaffold results in heightened stability of the guests, but no direct evidence of this mechanism has been shown. Here, we present a novel analytical method using small-angle X-ray scattering (SAXS) to solve the structure of bovine serum albumin (BSA) while encapsulated within two zeolitic imidazolate frameworks (ZIF-67 and ZIF-8). Our approach comprises subtracting the scaled SAXS spectrum of the ZIF from that of the biocomposite BSA@ZIF to determine the radius of gyration of encapsulated BSA through Guinier, Kratky, and pair distance distribution function analyses. While native BSA exposed to 70 °C became denatured, in situ SAXS analysis showed that encapsulated BSA retained its size and folded state at 70 °C when encapsulated within a ZIF scaffold, suggesting that entrapment within MOF cavities inhibited protein unfolding and thus denaturation. This method of SAXS analysis not only provides insight into biomolecular stabilization in MOFs but may also offer a new approach to study the structure of other conformationally labile molecules in rigid matrices.
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Affiliation(s)
- Rohan Murty
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Mrinal K Bera
- NSF's ChemMatCARS, Pritzker School of Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, United States
| | - Ian M Walton
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Christina Whetzel
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Mark R Prausnitz
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Krista S Walton
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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6
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Lee YT, Fan L, Ding J, Wang YX. Combining Biophysical Methods for Structure-Function Analyses of RNA in Solution. Methods Mol Biol 2023; 2568:165-177. [PMID: 36227568 DOI: 10.1007/978-1-0716-2687-0_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
RNA-level regulation by riboswitches relies on the specific binding of small metabolites to the aptamer domain to trigger substantial conformational changes that affect transcription or translation. Although several biophysical methods have been employed to study such RNAs, the utility of any one single method is limited. Hybrid approaches, therefore, are essential to better characterize these intrinsically dynamic molecules and elucidate their regulatory mechanisms driven by ligand-induced conformational changes. This chapter outlines procedures for biochemical and biophysical characterization of RNA that employs a combination of solution-based methods: isothermal titration calorimetry (ITC), small-angle X-ray scattering (SAXS), and atomic force microscopy (AFM). Collectively, these tools provide a semi-quantitative assessment of the thermodynamics associated with ligand binding and subsequent conformational changes.
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Affiliation(s)
- Yun-Tzai Lee
- Protein-Nucleic Acid Interaction Section, Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Lixin Fan
- Basic Science Program, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Jienyu Ding
- Protein-Nucleic Acid Interaction Section, Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Yun-Xing Wang
- Protein-Nucleic Acid Interaction Section, Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA.
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7
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Mertens HDT. Computational methods for the analysis of solution small-angle X-ray scattering of biomolecules: ATSAS. Methods Enzymol 2022; 678:193-236. [PMID: 36641208 DOI: 10.1016/bs.mie.2022.09.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The ATSAS software suite provides a comprehensive set of programs for the processing, analysis and modeling of small-angle scattering data, tailored for but not limited to data acquired on biological macromolecules. In this review the major components and developments in the ATSAS package are described, with a focus on user driven application. Data reduction, analysis and modeling approaches and strategies will be introduced and discussed. At the time of writing the latest package, ATSAS 3.1, is freely available for academic users at: https://www.embl-hamburg.de/biosaxs/software.html.
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8
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Gabel F, Engilberge S, Schmitt E, Thureau A, Mechulam Y, Pérez J, Girard E. Medical contrast agents as promising tools for biomacromolecular SAXS experiments. Acta Crystallogr D Struct Biol 2022; 78:1120-1130. [PMID: 36048152 PMCID: PMC9435597 DOI: 10.1107/s2059798322007392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 07/18/2022] [Indexed: 11/18/2022] Open
Abstract
Lanthanide-based complexes are presented as a promising class of molecules for efficient SAXS contrast-variation experiments. Their interactions and contrast properties are analyzed for an oligomeric protein and a protein–RNA complex. Small-angle X-ray scattering (SAXS) has become an indispensable tool in structural biology, complementing atomic-resolution techniques. It is sensitive to the electron-density difference between solubilized biomacromolecules and the buffer, and provides information on molecular masses, particle dimensions and interactions, low-resolution conformations and pair distance-distribution functions. When SAXS data are recorded at multiple contrasts, i.e. at different solvent electron densities, it is possible to probe, in addition to their overall shape, the internal electron-density profile of biomacromolecular assemblies. Unfortunately, contrast-variation SAXS has been limited by the range of solvent electron densities attainable using conventional co-solutes (for example sugars, glycerol and salt) and by the fact that some biological systems are destabilized in their presence. Here, SAXS contrast data from an oligomeric protein and a protein–RNA complex are presented in the presence of iohexol and Gd-HPDO3A, two electron-rich molecules that are used in biomedical imaging and that belong to the families of iodinated and lanthanide-based complexes, respectively. Moderate concentrations of both molecules allowed solvent electron densities matching those of proteins to be attained. While iohexol yielded higher solvent electron densities (per mole), it interacted specifically with the oligomeric protein and precipitated the protein–RNA complex. Gd-HPDO3A, while less efficient (per mole), did not disrupt the structural integrity of either system, and atomic models could be compared with the SAXS data. Due to their elevated solubility and electron density, their chemical inertness, as well as the possibility of altering their physico-chemical properties, lanthanide-based complexes represent a class of molecules with promising potential for contrast-variation SAXS experiments on diverse biomacromolecular systems.
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9
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Abstract
Proteins play a key role in living organisms. The study of proteins and their dynamics provides information about their functionality, catalysis and potential alterations towards pathological diseases. Several techniques are used for studying protein dynamics, e.g., magnetic resonance, fluorescence imaging techniques, mid-infrared spectroscopy and biochemical assays. Spectroscopic analysis, based on the use of terahertz (THz) radiation with frequencies between 0.1 and 15 THz (3–500 cm−1), was underestimated by the biochemical community. In recent years, however, the potential of THz spectroscopy in the analysis of both simple structures, such as polypeptide molecules, and complex structures, such as protein complexes, has been demonstrated. The THz absorption spectrum provides some information on proteins: for small molecules the THz spectrum is dominated by individual modes related to the presence of hydrogen bonds. For peptides, the spectral information concerns their secondary structure, while for complex proteins such as globular proteins and viral glycoproteins, spectra also provide information on collective modes. In this short review, we discuss the results obtained by THz spectroscopy in the protein dynamics investigations. In particular, we will illustrate advantages and applications of THz spectroscopy, pointing out the complementary information it may provide.
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10
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Bimetallic Copper/Ruthenium/Osmium Complexes: Observation of Conformational Differences Between the Solution Phase and Solid State by Atomic Pair Distribution Function Analysis. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202111764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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11
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Haslem L, Brown M, Zhang XA, Hays JM, Hays FA. Purification of Membrane Proteins Overexpressed in Saccharomyces cerevisiae. Methods Mol Biol 2022; 2507:143-173. [PMID: 35773581 PMCID: PMC9400948 DOI: 10.1007/978-1-0716-2368-8_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Membrane protein (MP) functional and structural characterization requires large quantities of high-purity protein for downstream studies. Barriers to MP characterization include ample overexpression, solubilization, and purification of target proteins while maintaining native activity and structure. These barriers can be overcome by utilizing an efficient purification protocol in a high-yield eukaryotic expression system such as Saccharomyces cerevisiae. S. cerevisiae offers improved protein folding and posttranslational modifications compared to prokaryotic expression systems. This chapter contains practices used to overcome barriers of solubilization and purification using S. cerevisiae that are broadly applicable to diverse membrane associated, and membrane integrated, protein targets.
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Affiliation(s)
- Landon Haslem
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Marina Brown
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Xin A Zhang
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Jennifer M Hays
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Franklin A Hays
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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12
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Xie ZL, Liu X, Valentine AJS, Lynch VM, Tiede DM, Li X, Mulfort KL. Bimetallic Copper/Ruthenium/Osmium Complexes: Observation of Conformational Differences Between the Solution Phase and Solid State by Atomic Pair Distribution Function Analysis. Angew Chem Int Ed Engl 2021; 61:e202111764. [PMID: 34788495 DOI: 10.1002/anie.202111764] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/26/2021] [Indexed: 11/10/2022]
Abstract
High-energy X-ray scattering and pair distribution function analysis (HEXS/PDF) is a powerful method to reveal the structure of materials lacking long-range order, but is underutilized for molecular complexes in solution. We demonstrate the application of HEXS/PDF with 0.26 Å resolution to uncover the solution structure of five bimetallic CuI /RuII /OsII complexes. HEXS/PDF of each complex in acetonitrile solution confirms the pairwise distances in the local coordination sphere of each metal center as well as the metal⋅⋅⋅metal distances separated by over 12 Å. The metal⋅⋅⋅metal distance detected in solution is compared with that from the crystal structure and molecular models to confirm that distortions to the metal bridging ligand are unique to the solid state. This work presents the first example of observing sub-Ångström conformational differences by direct comparison of solution phase and solid-state structures and shows the potential for HEXS/PDF in the determination of solution structure of single molecules.
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Affiliation(s)
- Zhu-Lin Xie
- Division of Chemical Sciences and Engineering, Argonne National Laboratory, 9700 S Cass Ave, Lemont, IL, 60439, USA
| | - Xiaolin Liu
- Department of Chemistry, University of Washington, 109 Bagley Hall, Seattle, WA, 98195-1700, USA
| | - Andrew J S Valentine
- Department of Chemistry, University of Washington, 109 Bagley Hall, Seattle, WA, 98195-1700, USA
| | - Vincent M Lynch
- Department of Chemistry, University of Texas at Austin, 105 E 24TH ST., Austin, TX, 78712-1224, USA
| | - David M Tiede
- Division of Chemical Sciences and Engineering, Argonne National Laboratory, 9700 S Cass Ave, Lemont, IL, 60439, USA
| | - Xiaosong Li
- Department of Chemistry, University of Washington, 109 Bagley Hall, Seattle, WA, 98195-1700, USA
| | - Karen L Mulfort
- Division of Chemical Sciences and Engineering, Argonne National Laboratory, 9700 S Cass Ave, Lemont, IL, 60439, USA
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13
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Zhou H, Wekesa JS, Luan Y, Meng J. PRPI-SC: an ensemble deep learning model for predicting plant lncRNA-protein interactions. BMC Bioinformatics 2021; 22:415. [PMID: 34429059 PMCID: PMC8385908 DOI: 10.1186/s12859-021-04328-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 11/09/2020] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Plant long non-coding RNAs (lncRNAs) play vital roles in many biological processes mainly through interactions with RNA-binding protein (RBP). To understand the function of lncRNAs, a fundamental method is to identify which types of proteins interact with the lncRNAs. However, the models or rules of interactions are a major challenge when calculating and estimating the types of RBP. RESULTS In this study, we propose an ensemble deep learning model to predict plant lncRNA-protein interactions using stacked denoising autoencoder and convolutional neural network based on sequence and structural information, named PRPI-SC. PRPI-SC predicts interactions between lncRNAs and proteins based on the k-mer features of RNAs and proteins. Experiments proved good results on Arabidopsis thaliana and Zea mays datasets (ATH948 and ZEA22133). The accuracy rates of ATH948 and ZEA22133 datasets were 88.9% and 82.6%, respectively. PRPI-SC also performed well on some public RNA protein interaction datasets. CONCLUSIONS PRPI-SC accurately predicts the interaction between plant lncRNA and protein, which plays a guiding role in studying the function and expression of plant lncRNA. At the same time, PRPI-SC has a strong generalization ability and good prediction effect for non-plant data.
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Affiliation(s)
- Haoran Zhou
- School of Computer Science and Technology, Dalian University of Technology, Dalian, 116024 Liaoning China
| | - Jael Sanyanda Wekesa
- School of Computer Science and Technology, Dalian University of Technology, Dalian, 116024 Liaoning China
| | - Yushi Luan
- School of Bioengineering, Dalian University of Technology, Dalian, 116024 Liaoning China
| | - Jun Meng
- School of Computer Science and Technology, Dalian University of Technology, Dalian, 116024 Liaoning China
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14
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Lundquist KP, Panchal V, Gotfredsen CH, Brenk R, Clausen MH. Fragment-Based Drug Discovery for RNA Targets. ChemMedChem 2021; 16:2588-2603. [PMID: 34101375 DOI: 10.1002/cmdc.202100324] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Indexed: 12/26/2022]
Abstract
Rapid development within the fields of both fragment-based drug discovery (FBDD) and medicinal targeting of RNA provides possibilities for combining technologies and methods in novel ways. This review provides an overview of fragment-based screening (FBS) against RNA targets, including a discussion of the most recently used screening and hit validation methods such as NMR spectroscopy, X-ray crystallography, and virtual screening methods. A discussion of fragment library design based on research from small-molecule RNA binders provides an overview on both the currently limited guidelines within RNA-targeting fragment library design, and future possibilities. Finally, future perspectives are provided on screening and hit validation methods not yet used in combination with both fragment screening and RNA targets.
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Affiliation(s)
- Kasper P Lundquist
- Center for Nanomedicine and Theranostics, Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800, Kgs. Lyngby, Denmark
| | - Vipul Panchal
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5020, Bergen, Norway
| | - Charlotte H Gotfredsen
- NMR Center ⋅ DTU, Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800, Kgs. Lyngby, Denmark
| | - Ruth Brenk
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5020, Bergen, Norway
| | - Mads H Clausen
- Center for Nanomedicine and Theranostics, Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800, Kgs. Lyngby, Denmark
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15
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Li J, Chen SJ. RNA 3D Structure Prediction Using Coarse-Grained Models. Front Mol Biosci 2021; 8:720937. [PMID: 34277713 PMCID: PMC8283274 DOI: 10.3389/fmolb.2021.720937] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 06/17/2021] [Indexed: 12/12/2022] Open
Abstract
The three-dimensional (3D) structures of Ribonucleic acid (RNA) molecules are essential to understanding their various and important biological functions. However, experimental determination of the atomic structures is laborious and technically difficult. The large gap between the number of sequences and the experimentally determined structures enables the thriving development of computational approaches to modeling RNAs. However, computational methods based on all-atom simulations are intractable for large RNA systems, which demand long time simulations. Facing such a challenge, many coarse-grained (CG) models have been developed. Here, we provide a review of CG models for modeling RNA 3D structures, compare the performance of the different models, and offer insights into potential future developments.
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Affiliation(s)
| | - Shi-Jie Chen
- Departments of Physics and Biochemistry, and Institute of Data Science and Informatics, University of Missouri, Columbia, MO, United States
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16
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Poddar H, Heyes DJ, Schirò G, Weik M, Leys D, Scrutton NS. A guide to time-resolved structural analysis of light-activated proteins. FEBS J 2021; 289:576-595. [PMID: 33864718 DOI: 10.1111/febs.15880] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/03/2021] [Accepted: 04/13/2021] [Indexed: 01/08/2023]
Abstract
Dynamical changes in protein structures are essential for protein function and occur over femtoseconds to seconds timescales. X-ray free electron lasers have facilitated investigations of structural dynamics in proteins with unprecedented temporal and spatial resolution. Light-activated proteins are attractive targets for time-resolved structural studies, as the reaction chemistry and associated protein structural changes can be triggered by short laser pulses. Proteins with different light-absorbing centres have evolved to detect light and harness photon energy to bring about downstream chemical and biological output responses. Following light absorption, rapid chemical/small-scale structural changes are typically localised around the chromophore. These localised changes are followed by larger structural changes propagated throughout the photoreceptor/photocatalyst that enables the desired chemical and/or biological output response. Time-resolved serial femtosecond crystallography (SFX) and solution scattering techniques enable direct visualisation of early chemical change in light-activated proteins on timescales previously inaccessible, whereas scattering gives access to slower timescales associated with more global structural change. Here, we review how advances in time-resolved SFX and solution scattering techniques have uncovered mechanisms of photochemistry and its coupling to output responses. We also provide a prospective on how these time-resolved structural approaches might impact on other photoreceptors/photoenzymes that have not yet been studied by these methods.
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Affiliation(s)
- Harshwardhan Poddar
- Manchester Institute of Biotechnology, Department of Chemistry, University of Manchester, UK
| | - Derren J Heyes
- Manchester Institute of Biotechnology, Department of Chemistry, University of Manchester, UK
| | - Giorgio Schirò
- Institut de Biologie Structurale, Univ. Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Martin Weik
- Institut de Biologie Structurale, Univ. Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - David Leys
- Manchester Institute of Biotechnology, Department of Chemistry, University of Manchester, UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology, Department of Chemistry, University of Manchester, UK
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17
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Manalastas-Cantos K, Konarev PV, Hajizadeh NR, Kikhney AG, Petoukhov MV, Molodenskiy DS, Panjkovich A, Mertens HDT, Gruzinov A, Borges C, Jeffries CM, Svergun DI, Franke D. ATSAS 3.0: expanded functionality and new tools for small-angle scattering data analysis. J Appl Crystallogr 2021; 54:343-355. [PMID: 33833657 PMCID: PMC7941305 DOI: 10.1107/s1600576720013412] [Citation(s) in RCA: 420] [Impact Index Per Article: 140.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 10/06/2020] [Indexed: 11/11/2022] Open
Abstract
The ATSAS software suite encompasses a number of programs for the processing, visualization, analysis and modelling of small-angle scattering data, with a focus on the data measured from biological macromolecules. Here, new developments in the ATSAS 3.0 package are described. They include IMSIM, for simulating isotropic 2D scattering patterns; IMOP, to perform operations on 2D images and masks; DATRESAMPLE, a method for variance estimation of structural invariants through parametric resampling; DATFT, which computes the pair distance distribution function by a direct Fourier transform of the scattering data; PDDFFIT, to compute the scattering data from a pair distance distribution function, allowing comparison with the experimental data; a new module in DATMW for Bayesian consensus-based concentration-independent molecular weight estimation; DATMIF, an ab initio shape analysis method that optimizes the search model directly against the scattering data; DAMEMB, an application to set up the initial search volume for multiphase modelling of membrane proteins; ELLLIP, to perform quasi-atomistic modelling of liposomes with elliptical shapes; NMATOR, which models conformational changes in nucleic acid structures through normal mode analysis in torsion angle space; DAMMIX, which reconstructs the shape of an unknown intermediate in an evolving system; and LIPMIX and BILMIX, for modelling multilamellar and asymmetric lipid vesicles, respectively. In addition, technical updates were deployed to facilitate maintainability of the package, which include porting the PRIMUS graphical interface to Qt5, updating SASpy - a PyMOL plugin to run a subset of ATSAS tools - to be both Python 2 and 3 compatible, and adding utilities to facilitate mmCIF compatibility in future ATSAS releases. All these features are implemented in ATSAS 3.0, freely available for academic users at https://www.embl-hamburg.de/biosaxs/software.html.
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Affiliation(s)
- Karen Manalastas-Cantos
- European Molecular Biology Laboratory, Hamburg Site, Notkestrasse 85, Building 25 A, Hamburg, 22607, Germany
| | - Petr V. Konarev
- A.V. Shubnikov Institute of Crystallography, Federal Scientific Research Centre ‘Crystallography and Photonics’ of Russian Academy of Sciences, Leninsky prospekt 59, Moscow, 119333, Russian Federation
| | - Nelly R. Hajizadeh
- European Molecular Biology Laboratory, Hamburg Site, Notkestrasse 85, Building 25 A, Hamburg, 22607, Germany
| | - Alexey G. Kikhney
- European Molecular Biology Laboratory, Hamburg Site, Notkestrasse 85, Building 25 A, Hamburg, 22607, Germany
| | - Maxim V. Petoukhov
- A.V. Shubnikov Institute of Crystallography, Federal Scientific Research Centre ‘Crystallography and Photonics’ of Russian Academy of Sciences, Leninsky prospekt 59, Moscow, 119333, Russian Federation
| | - Dmitry S. Molodenskiy
- European Molecular Biology Laboratory, Hamburg Site, Notkestrasse 85, Building 25 A, Hamburg, 22607, Germany
| | - Alejandro Panjkovich
- European Molecular Biology Laboratory, Hamburg Site, Notkestrasse 85, Building 25 A, Hamburg, 22607, Germany
| | - Haydyn D. T. Mertens
- European Molecular Biology Laboratory, Hamburg Site, Notkestrasse 85, Building 25 A, Hamburg, 22607, Germany
| | - Andrey Gruzinov
- European Molecular Biology Laboratory, Hamburg Site, Notkestrasse 85, Building 25 A, Hamburg, 22607, Germany
| | - Clemente Borges
- European Molecular Biology Laboratory, Hamburg Site, Notkestrasse 85, Building 25 A, Hamburg, 22607, Germany
| | - Cy M. Jeffries
- European Molecular Biology Laboratory, Hamburg Site, Notkestrasse 85, Building 25 A, Hamburg, 22607, Germany
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory, Hamburg Site, Notkestrasse 85, Building 25 A, Hamburg, 22607, Germany
| | - Daniel Franke
- European Molecular Biology Laboratory, Hamburg Site, Notkestrasse 85, Building 25 A, Hamburg, 22607, Germany
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18
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Ramanathan A, Ma H, Parvatikar A, Chennubhotla SC. Artificial intelligence techniques for integrative structural biology of intrinsically disordered proteins. Curr Opin Struct Biol 2021; 66:216-224. [PMID: 33421906 DOI: 10.1016/j.sbi.2020.12.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/01/2020] [Accepted: 12/03/2020] [Indexed: 12/16/2022]
Abstract
We outline recent developments in artificial intelligence (AI) and machine learning (ML) techniques for integrative structural biology of intrinsically disordered proteins (IDP) ensembles. IDPs challenge the traditional protein structure-function paradigm by adapting their conformations in response to specific binding partners leading them to mediate diverse, and often complex cellular functions such as biological signaling, self-organization and compartmentalization. Obtaining mechanistic insights into their function can therefore be challenging for traditional structural determination techniques. Often, scientists have to rely on piecemeal evidence drawn from diverse experimental techniques to characterize their functional mechanisms. Multiscale simulations can help bridge critical knowledge gaps about IDP structure-function relationships-however, these techniques also face challenges in resolving emergent phenomena within IDP conformational ensembles. We posit that scalable statistical inference techniques can effectively integrate information gleaned from multiple experimental techniques as well as from simulations, thus providing access to atomistic details of these emergent phenomena.
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Affiliation(s)
- Arvind Ramanathan
- Data Science & Learning Division, Argonne National Laboratory, Lemont, IL 60439, United States; Consortium for Advanced Science and Engineering (CASE), University of Chicago, Hyde Park, IL, United States.
| | - Heng Ma
- Data Science & Learning Division, Argonne National Laboratory, Lemont, IL 60439, United States
| | - Akash Parvatikar
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - S Chakra Chennubhotla
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA 15260, United States
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19
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Angular super-resolution retrieval in small-angle X-ray scattering. Sci Rep 2020; 10:16038. [PMID: 32994517 PMCID: PMC7525553 DOI: 10.1038/s41598-020-73030-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/31/2020] [Indexed: 11/21/2022] Open
Abstract
Small-angle X-ray scattering (SAXS) techniques enable convenient nanoscopic characterization for various systems and conditions. Unlike synchrotron-based setups, lab-based SAXS systems intrinsically suffer from lower X-ray flux and limited angular resolution. Here, we develop a two-step retrieval methodology to enhance the angular resolution for given experimental conditions. Using minute hardware additions, we show that translating the X-ray detector in subpixel steps and modifying the incoming beam shape results in a set of 2D scattering images, which is sufficient for super-resolution SAXS retrieval. The technique is verified experimentally to show superior resolution. Such advantages have a direct impact on the ability to resolve finer nanoscopic structures and can be implemented in most existing SAXS apparatuses both using synchrotron- and laboratory-based sources.
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20
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Matsarskaia O, Roosen‐Runge F, Schreiber F. Multivalent ions and biomolecules: Attempting a comprehensive perspective. Chemphyschem 2020; 21:1742-1767. [PMID: 32406605 PMCID: PMC7496725 DOI: 10.1002/cphc.202000162] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/13/2020] [Indexed: 12/13/2022]
Abstract
Ions are ubiquitous in nature. They play a key role for many biological processes on the molecular scale, from molecular interactions, to mechanical properties, to folding, to self-organisation and assembly, to reaction equilibria, to signalling, to energy and material transport, to recognition etc. Going beyond monovalent ions to multivalent ions, the effects of the ions are frequently not only stronger (due to the obviously higher charge), but qualitatively different. A typical example is the process of binding of multivalent ions, such as Ca2+ , to a macromolecule and the consequences of this ion binding such as compaction, collapse, potential charge inversion and precipitation of the macromolecule. Here we review these effects and phenomena induced by multivalent ions for biological (macro)molecules, from the "atomistic/molecular" local picture of (potentially specific) interactions to the more global picture of phase behaviour including, e. g., crystallisation, phase separation, oligomerisation etc. Rather than attempting an encyclopedic list of systems, we rather aim for an embracing discussion using typical case studies. We try to cover predominantly three main classes: proteins, nucleic acids, and amphiphilic molecules including interface effects. We do not cover in detail, but make some comparisons to, ion channels, colloidal systems, and synthetic polymers. While there are obvious differences in the behaviour of, and the relevance of multivalent ions for, the three main classes of systems, we also point out analogies. Our attempt of a comprehensive discussion is guided by the idea that there are not only important differences and specific phenomena with regard to the effects of multivalent ions on the main systems, but also important similarities. We hope to bridge physico-chemical mechanisms, concepts of soft matter, and biological observations and connect the different communities further.
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Affiliation(s)
| | - Felix Roosen‐Runge
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and SocietyMalmö UniversitySweden
- Division of Physical ChemistryLund UniversitySweden
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21
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Esteban Florez FL, Trofimov AA, Ievlev A, Qian S, Rondinone AJ, Khajotia SS. Advanced characterization of surface-modified nanoparticles and nanofilled antibacterial dental adhesive resins. Sci Rep 2020; 10:9811. [PMID: 32555360 PMCID: PMC7299952 DOI: 10.1038/s41598-020-66819-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/21/2020] [Indexed: 11/30/2022] Open
Abstract
Nanotechnology can improve the performance of dental polymers. The objective of this study was to modify the surfaces of nanoparticles with silanes and proteins, characterize nanoparticles' agglomeration levels and interfaces between nanoparticles and the polymeric matrix. Undoped (n-TiO2), nitrogen-doped (N_TiO2) and nitrogen-fluorine co-doped titanium dioxide nanoparticles (NF_TiO2) were synthesized and subjected to surface modification procedures in preparation for Small-Angle X-Ray Scattering (SAXS) and Small-Angle Neutron Scattering (SANS) characterizations. Experimental adhesives were manually synthesized by incorporating 20% (v/v) of n-TiO2, N_TiO2 or NF_TiO2 (as-synthesized or surface-modified) into OptiBond Solo Plus (OPTB). Specimens (n = 15/group; d = 6.0 mm, t = 0.5 mm) of OPTB and experimental adhesives were characterized using Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS), 2-D ToF-SIMS chemical imaging and SANS. SAXS results indicated that surface-modified nanoparticles displayed higher scattering intensities in a particle-size dependent manner. ToF-SIMS results demonstrated that nanoparticles' incorporation did not adversely impact the parental polymer. 2-D ToF-SIMS chemical imaging demonstrated the distribution of Ti+ and confirmed nitrogen-doping levels. SANS results confirmed nanoparticles' functionalization and revealed the interfaces between nanoparticles and the polymer matrix. Metaloxide nanoparticles were successfully fabricated, incorporated and covalently functionalized in a commercial dental adhesive resin, thereby supporting the utilization of nanotechnology in dentistry.
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Affiliation(s)
- Fernando Luis Esteban Florez
- The University of Oklahoma Health Sciences Center, Department of Restorative Sciences, Division of Dental Biomaterials, College of Dentistry, 1201 N. Stonewall Avenue, Oklahoma City, Oklahoma, 73117, USA.
| | - Artem A Trofimov
- Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, Oak Ridge, Tennessee, 37831, USA
| | - Anton Ievlev
- Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, Oak Ridge, Tennessee, 37831, USA
| | - Shuo Qian
- Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, Tennessee, 37831, USA
| | - Adam Justin Rondinone
- Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, Oak Ridge, Tennessee, 37831, USA
| | - Sharukh Soli Khajotia
- The University of Oklahoma Health Sciences Center, Department of Restorative Sciences, Division of Dental Biomaterials, College of Dentistry, 1201 N. Stonewall Avenue, Oklahoma City, Oklahoma, 73117, USA
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22
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Zhao S, Todorov MI, Cai R, -Maskari RA, Steinke H, Kemter E, Mai H, Rong Z, Warmer M, Stanic K, Schoppe O, Paetzold JC, Gesierich B, Wong MN, Huber TB, Duering M, Bruns OT, Menze B, Lipfert J, Puelles VG, Wolf E, Bechmann I, Ertürk A. Cellular and Molecular Probing of Intact Human Organs. Cell 2020; 180:796-812.e19. [PMID: 32059778 PMCID: PMC7557154 DOI: 10.1016/j.cell.2020.01.030] [Citation(s) in RCA: 138] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 12/04/2019] [Accepted: 01/22/2020] [Indexed: 12/16/2022]
Abstract
Optical tissue transparency permits scalable cellular and molecular investigation of complex tissues in 3D. Adult human organs are particularly challenging to render transparent because of the accumulation of dense and sturdy molecules in decades-aged tissues. To overcome these challenges, we developed SHANEL, a method based on a new tissue permeabilization approach to clear and label stiff human organs. We used SHANEL to render the intact adult human brain and kidney transparent and perform 3D histology with antibodies and dyes in centimeters-depth. Thereby, we revealed structural details of the intact human eye, human thyroid, human kidney, and transgenic pig pancreas at the cellular resolution. Furthermore, we developed a deep learning pipeline to analyze millions of cells in cleared human brain tissues within hours with standard lab computers. Overall, SHANEL is a robust and unbiased technology to chart the cellular and molecular architecture of large intact mammalian organs.
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Affiliation(s)
- Shan Zhao
- Insititute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University of Munich (LMU), 81377 Munich, Germany; Munich Medical Research School (MMRS), 80336 Munich, Germany
| | - Mihail Ivilinov Todorov
- Insititute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University of Munich (LMU), 81377 Munich, Germany; Graduate School of Neuroscience (GSN), 82152 Munich, Germany
| | - Ruiyao Cai
- Insititute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University of Munich (LMU), 81377 Munich, Germany
| | - Rami Ai -Maskari
- Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University of Munich (LMU), 81377 Munich, Germany; Department of Computer Science, Technical University of Munich (TUM), 81675 Munich, Germany; Center for Translational Cancer Research (TranslaTUM) of the TUM, 80798 Munich, Germany; Graduate School of Bioengineering, Technical University of Munich (TUM), 85748 Munich, Germany
| | - Hanno Steinke
- Institute of Anatomy, University of Leipzig, 04109 Leipzig, Germany
| | - Elisabeth Kemter
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, Ludwig Maximilian University of Munich (LMU), 81377 Munich, Germany; Center for Innovative Medical Models (CiMM), 85764 Oberschleißheim, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Hongcheng Mai
- Insititute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University of Munich (LMU), 81377 Munich, Germany
| | - Zhouyi Rong
- Insititute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University of Munich (LMU), 81377 Munich, Germany
| | - Martin Warmer
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Karen Stanic
- Insititute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Oliver Schoppe
- Department of Computer Science, Technical University of Munich (TUM), 81675 Munich, Germany; Center for Translational Cancer Research (TranslaTUM) of the TUM, 80798 Munich, Germany
| | - Johannes Christian Paetzold
- Department of Computer Science, Technical University of Munich (TUM), 81675 Munich, Germany; Center for Translational Cancer Research (TranslaTUM) of the TUM, 80798 Munich, Germany; Graduate School of Bioengineering, Technical University of Munich (TUM), 85748 Munich, Germany
| | - Benno Gesierich
- Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University of Munich (LMU), 81377 Munich, Germany
| | - Milagros N Wong
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Tobias B Huber
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Marco Duering
- Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University of Munich (LMU), 81377 Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Oliver Thomas Bruns
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Bjoern Menze
- Department of Computer Science, Technical University of Munich (TUM), 81675 Munich, Germany; Center for Translational Cancer Research (TranslaTUM) of the TUM, 80798 Munich, Germany; Graduate School of Bioengineering, Technical University of Munich (TUM), 85748 Munich, Germany
| | - Jan Lipfert
- Department of Physics and Center for Nanoscience, Ludwig Maximilian University of Munich (LMU), 80799 Munich, Germany
| | - Victor G Puelles
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; Department of Nephrology, Monash Health, and Center for Inflammatory Diseases, Monash University, Melbourne VIC 3168, Australia
| | - Eckhard Wolf
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, Ludwig Maximilian University of Munich (LMU), 81377 Munich, Germany; Center for Innovative Medical Models (CiMM), 85764 Oberschleißheim, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Ingo Bechmann
- Institute of Anatomy, University of Leipzig, 04109 Leipzig, Germany
| | - Ali Ertürk
- Insititute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University of Munich (LMU), 81377 Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany.
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23
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Théobald-Dietrich A, de Wijn R, Rollet K, Bluhm A, Rudinger-Thirion J, Paulus C, Lorber B, Thureau A, Frugier M, Sauter C. Structural Analysis of RNA by Small-Angle X-ray Scattering. Methods Mol Biol 2020; 2113:189-215. [PMID: 32006316 DOI: 10.1007/978-1-0716-0278-2_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Over the past two decades small-angle X-ray scattering (SAXS) has become a popular method to characterize solutions of biomolecules including ribonucleic acid (RNA). In an integrative structural approach, SAXS is complementary to crystallography, NMR, and electron microscopy and provides information about RNA architecture and dynamics. This chapter highlights the practical advantages of combining size-exclusion chromatography and SAXS at synchrotron facilities. It is illustrated by practical case studies of samples ranging from single hairpins and tRNA to a large IRES. The emphasis is also put on sample preparation which is a critical step of SAXS analysis and on optimized protocols for in vitro RNA synthesis ensuring the production of mg amount of pure and homogeneous molecules.
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Affiliation(s)
- Anne Théobald-Dietrich
- Architecture et Réactivité de l'ARN, UPR 9002, IBMC, CNRS, Université de Strasbourg, Strasbourg, France
| | - Raphaël de Wijn
- Architecture et Réactivité de l'ARN - CNRS UPR 9002, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
| | - Kévin Rollet
- Architecture et Réactivité de l'ARN - CNRS UPR 9002, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
| | - Alexandra Bluhm
- Architecture et Réactivité de l'ARN, UPR 9002, IBMC, CNRS, Université de Strasbourg, Strasbourg, France
| | - Joëlle Rudinger-Thirion
- Architecture et Réactivité de l'ARN - CNRS UPR 9002, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
| | - Caroline Paulus
- Architecture et Réactivité de l'ARN - CNRS UPR 9002, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
| | - Bernard Lorber
- Architecture et Réactivité de l'ARN - CNRS UPR 9002, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
| | | | - Magali Frugier
- Architecture et Réactivité de l'ARN - CNRS UPR 9002, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
| | - Claude Sauter
- Architecture et Réactivité de l'ARN - CNRS UPR 9002, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France.
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24
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Badaczewska-Dawid AE, Kolinski A, Kmiecik S. Computational reconstruction of atomistic protein structures from coarse-grained models. Comput Struct Biotechnol J 2019; 18:162-176. [PMID: 31969975 PMCID: PMC6961067 DOI: 10.1016/j.csbj.2019.12.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 12/10/2019] [Indexed: 01/02/2023] Open
Abstract
Three-dimensional protein structures, whether determined experimentally or theoretically, are often too low resolution. In this mini-review, we outline the computational methods for protein structure reconstruction from incomplete coarse-grained to all atomistic models. Typical reconstruction schemes can be divided into four major steps. Usually, the first step is reconstruction of the protein backbone chain starting from the C-alpha trace. This is followed by side-chains rebuilding based on protein backbone geometry. Subsequently, hydrogen atoms can be reconstructed. Finally, the resulting all-atom models may require structure optimization. Many methods are available to perform each of these tasks. We discuss the available tools and their potential applications in integrative modeling pipelines that can transfer coarse-grained information from computational predictions, or experiment, to all atomistic structures.
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Affiliation(s)
| | | | - Sebastian Kmiecik
- Faculty of Chemistry, Biological and Chemical Research Center, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
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25
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Balu R, Knott R, Elvin CM, Hill AJ, R Choudhury N, Dutta NK. A Sustainable Biomineralization Approach for the Synthesis of Highly Fluorescent Ultra-Small Pt Nanoclusters. BIOSENSORS 2019; 9:E128. [PMID: 31671878 PMCID: PMC6956208 DOI: 10.3390/bios9040128] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/16/2019] [Accepted: 10/21/2019] [Indexed: 11/17/2022]
Abstract
Herein we report the first example of a facile biomineralization process to produce ultra-small-sized highly fluorescent aqueous dispersions of platinum noble metal quantum clusters (Pt-NMQCs) using a multi-stimulus responsive, biomimetic intrinsically disordered protein (IDP), Rec1-resilin. We demonstrate that Rec1-resilin acts concurrently as the host, reducing agent, and stabilizer of the blue-green fluorescent Pt-NMQCs once they are being formed. The photophysical properties, quantum yield, and fluorescence lifetime measurements of the synthesized Pt-NMQCs were examined using UV-Vis and fluorescence spectroscopy. The oxidation state of the Pt-NMQCs was quantitatively analyzed using X-ray photoelectron spectroscopy. Both a small angle X-ray scattering technique and a modeling approach have been attempted to present a detailed understanding of the structure and conformational dynamics of Rec1-resilin as an IDP during the formation of the Pt-NMQCs. It has been demonstrated that the green fluorescent Pt-NMQCs exhibit a high quantum yield of ~7.0% and a lifetime of ~9.5 ns in aqueous media. The change in photoluminescence properties due to the inter-dot interactions between proximal dots and aggregation of the Pt-NMQCs by evaporation was also measured spectroscopically and discussed.
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Affiliation(s)
- Rajkamal Balu
- Chemical and Environment Engineering, School of Engineering, RMIT University, Melbourne, VIC 3000, Australia.
| | - Robert Knott
- Australian Centre for Neutron Scattering (ACNS), Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia.
| | - Christopher M Elvin
- CSIRO Agriculture, Level 6, Queensland Bioscience Precinct, St Lucia, QLD 4067, Australia.
| | - Anita J Hill
- CSIRO Manufacturing, Bayview Ave, Clayton, VIC 3168, Australia.
| | - Namita R Choudhury
- Chemical and Environment Engineering, School of Engineering, RMIT University, Melbourne, VIC 3000, Australia.
| | - Naba K Dutta
- Chemical and Environment Engineering, School of Engineering, RMIT University, Melbourne, VIC 3000, Australia.
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26
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Krishnamoorthy K, Kewalramani S, Ehlen A, Moreau LM, Mirkin CA, Olvera de la Cruz M, Bedzyk MJ. Enzymatic Degradation of DNA Probed by In Situ X-ray Scattering. ACS NANO 2019; 13:11382-11391. [PMID: 31513370 DOI: 10.1021/acsnano.9b04752] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Label-free in situ X-ray scattering from protein spherical nucleic acids (Pro-SNAs, consisting of protein cores densely functionalized with covalently bound DNA) was used to elucidate the enzymatic reaction pathway for the DNase I-induced degradation of DNA. Time-course small-angle X-ray scattering (SAXS) and gel electrophoresis reveal a two-state system with time-dependent populations of intact and fully degraded DNA in the Pro-SNAs. SAXS shows that in the fully degraded state, the DNA strands forming the outer shell of the Pro-SNA were completely digested. SAXS analysis of reactions with different Pro-SNA concentrations reveals a reaction pathway characterized by a slow, rate determining DNase I-Pro-SNA association, followed by rapid DNA hydrolysis. Molecular dynamics (MD) simulations provide the distributions of monovalent and divalent ions around the Pro-SNA, relevant to the activity of DNase I. Taken together, in situ SAXS in conjunction with MD simulations yield key mechanistic and structural insights into the interaction of DNA with DNase I. The approach presented here should prove invaluable in probing other enzyme-catalyzed reactions on the nanoscale.
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27
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Gabel F, Engilberge S, Pérez J, Girard E. Medical contrast media as possible tools for SAXS contrast variation. IUCRJ 2019; 6:521-525. [PMID: 31316796 PMCID: PMC6608644 DOI: 10.1107/s2052252519005943] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 04/29/2019] [Indexed: 05/26/2023]
Abstract
Small-angle X-ray scattering (SAXS) is increasingly used to extract structural information from a multitude of soft-matter and biological systems in aqueous solution, including polymers, detergents, lipids, colloids, proteins and RNA/DNA. When SAXS data are recorded at multiple contrasts, i.e. at different electron densities of the solvent, the internal electron-density profile of solubilized molecular systems can be probed. However, contrast-variation SAXS has been limited by the range of electron densities available by conventional agents such as sugars, glycerol and salt, and by the fact that many soft-matter and biological systems are modified in their presence. Here we present a pioneering SAXS contrast-variation study on DDM (n-do-decyl-β-d-malto-pyran-oside) micelles by using two highly electron-rich contrast agents from biomedical imaging which belong to the families of gadolinium-based and iodinated molecules. The two agents, Gd-HPDO3A and iohexol, were allowed to attain modifications of the solvent electron density that are 50 to 100% higher than those obtained for sucrose, and are located between the electron densities of proteins and RNA/DNA. In the case of Gd-HPDO3A, an analysis of the internal micellar structure was possible and compared with results obtained with sucrose. In conclusion, medical contrast agents represent a promising class of molecules for SAXS contrast-variation experiments with potential appli-cations for numerous soft-matter and biological systems, including membrane proteins and protein-RNA/DNA complexes.
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Affiliation(s)
- Frank Gabel
- IBS, CEA, CNRS, UGA, 71 avenue des Martyrs, 38000 Grenoble, France
| | | | - Javier Pérez
- Synchrotron SOLEIL, Saint-Aubin BP 48, 91192 Gif-sur-Yvette, France
| | - Eric Girard
- IBS, CEA, CNRS, UGA, 71 avenue des Martyrs, 38000 Grenoble, France
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28
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Kumar S, Yadav I, Ray D, Abbas S, Saha D, Aswal VK, Kohlbrecher J. Evolution of Interactions in the Protein Solution As Induced by Mono and Multivalent Ions. Biomacromolecules 2019; 20:2123-2134. [PMID: 30908911 DOI: 10.1021/acs.biomac.9b00374] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The evolution of interactions in the bovine serum albumin (BSA) protein solution on addition of mono and multivalent (di, tri and tetra) counterions has been studied using small-angle neutron scattering (SANS), dynamic light scattering (DLS) and ζ-potential measurements. It is found that in the presence of mono and divalent counterions, protein behavior can be well explained by DLVO theory, combining the contributions of screened Coulomb repulsion with the van der Waals attraction. The addition of mono or divalent salts in protein solution reduces the repulsive barrier and hence the overall interaction becomes attractive, but the system remains in one-phase for the entire concentration range of the salts, added in the system. However, contrary to DLVO theory, the protein solution undergoes a reentrant phase transition from one-phase to a two-phase system and then back to the one-phase system in the presence of tri and tetravalent counterions. The results show that tri and tetravalent (unlike mono and divalent) counterions induce short-range attraction between the protein molecules, leading to the transformation from one-phase to two-phase system. The two-phase is characterized by the fractal structure of protein aggregates. The excess condensation of these higher-valent counterions in the double layer around the BSA causes the reversal of charge of the protein molecules resulting into reentrant of the one-phase, at higher salt concentrations. The complete phase behavior with mono and multivalent ions has been explained in terms of the interplay of electrostatic repulsion and ion-induced short-range attraction between the protein molecules.
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Affiliation(s)
- Sugam Kumar
- Solid State Physics Division , Bhabha Atomic Research Centre , Mumbai 400 085 , India.,Division of Materials and Environmental Chemistry , Stockholm University , Frescativagen 8 , Stockholm 10691 , Sweden
| | - Indresh Yadav
- Solid State Physics Division , Bhabha Atomic Research Centre , Mumbai 400 085 , India
| | - Debes Ray
- Solid State Physics Division , Bhabha Atomic Research Centre , Mumbai 400 085 , India
| | - Sohrab Abbas
- Solid State Physics Division , Bhabha Atomic Research Centre , Mumbai 400 085 , India
| | - Debasish Saha
- Solid State Physics Division , Bhabha Atomic Research Centre , Mumbai 400 085 , India.,Department of Science and Technology , New Delhi 110016 , India
| | - Vinod K Aswal
- Solid State Physics Division , Bhabha Atomic Research Centre , Mumbai 400 085 , India.,Homi Bhabha National Institute , Mumbai 400 094 , India
| | - Joachim Kohlbrecher
- Laboratory for Neutron Scattering, Paul Scherrer Institut , CH-5232 PSI Villigen , Switzerland
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29
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Balu R, Choudhury NR, Mata JP, de Campo L, Rehm C, Hill AJ, Dutta NK. Evolution of the Interfacial Structure of a Catalyst Ink with the Quality of the Dispersing Solvent: A Contrast Variation Small-Angle and Ultrasmall-Angle Neutron Scattering Investigation. ACS APPLIED MATERIALS & INTERFACES 2019; 11:9934-9946. [PMID: 30762351 DOI: 10.1021/acsami.8b20645] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The electrocatalyst layer (ECL) of the proton-exchange membrane fuel cell (PEMFC) is commonly fabricated from colloidal catalyst ink containing carbon-supported catalyst nanoparticles (NPs), ionomer stabilizer, and dispersion medium (DM). The structure, stability, and aggregate size distribution of fuel cell catalyst ink are critically dependent on the quality of DM. However, understanding of the influence of the quality of DM on the hierarchical structure of the ECL is lacking. This work presents a systematic investigation of the effects of reducing alcohol content in isopropyl alcohol/water (IPA/H2O) binary mixtures as DM on the structural evolution of water-rich (green) catalyst ink using contrast-variation small-angle and ultrasmall-angle neutron scattering techniques. Both qualitative and quantitative information are extracted from the data to obtain information about the size, structure, and organization of the catalyst ink using different model functions fit to the experimental data. The catalyst ink prepared using 70% IPA (commonly employed in industry and extensively reported in the literature) is shown to consist of randomly distributed globular carbon aggregates (mean radius of gyration of ∼178.9 nm) stabilized by an ionomer mass fractal shell (thickness of ∼13.0 nm), which is dispersed in the matrix of rodlike (∼1.3 nm radius and ∼35.0 nm length) negatively surface-charged ionomer NPs. These well characterized baseline data are then compared and contrasted with DM formulations of lower IPA content. A sequential reduction in IPA content of DM shows a progressive increase in the ionomer NP radius and electrostatic repulsion, concomitantly with the decrease in the carbon aggregate size and ionomer shell thickness of the catalyst ink. Therefore, the changes in the interfacial structure via adjustments of the DM composition can be used as a controlling parameter to tailor the hierarchical structure of the colloidal fuel cell catalyst ink and to further optimize the performance of the ECL.
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Affiliation(s)
- Rajkamal Balu
- Chemical and Environmental Engineering, School of Engineering , RMIT University , Melbourne , Victoria 3000 , Australia
| | - Namita Roy Choudhury
- Chemical and Environmental Engineering, School of Engineering , RMIT University , Melbourne , Victoria 3000 , Australia
| | - Jitendra P Mata
- Australian Centre for Neutron Scattering (ACNS) , Australian Nuclear Science and Technology Organisation (ANSTO) , Lucas Heights , New South Wales 2234 , Australia
| | - Liliana de Campo
- Australian Centre for Neutron Scattering (ACNS) , Australian Nuclear Science and Technology Organisation (ANSTO) , Lucas Heights , New South Wales 2234 , Australia
| | - Christine Rehm
- Australian Centre for Neutron Scattering (ACNS) , Australian Nuclear Science and Technology Organisation (ANSTO) , Lucas Heights , New South Wales 2234 , Australia
- Guangdong Technion Israel Institute of Technology, Shantou , Guangdong Province 515063 , People's Republic of China
| | - Anita J Hill
- CSIRO Manufacturing , Bayview Avenue , Clayton , Victoria 3168 , Australia
| | - Naba K Dutta
- Chemical and Environmental Engineering, School of Engineering , RMIT University , Melbourne , Victoria 3000 , Australia
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30
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In-situ aerosol nanoparticle characterization by small angle X-ray scattering at ultra-low volume fraction. Nat Commun 2019; 10:1122. [PMID: 30850597 PMCID: PMC6408461 DOI: 10.1038/s41467-019-09066-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 02/15/2019] [Indexed: 11/08/2022] Open
Abstract
State-of-the-art aerosol nanoparticle techniques all have one feature in common: for analysis they remove the nanoparticles from their original environment. Therefore, physical and chemical properties of the particles might be changed or cannot be measured correctly. To overcome these shortcomings, we apply synchrotron based small angle X-ray scattering (SAXS) as an in-situ measurement technique. Contrasting other aerosol studies using SAXS, we focus on particle concentrations which allow direct comparison to common aerosol nanoparticle analyzers. To this end, we analyze aerosol nanoparticles at ambient pressure and concentrations of slightly above ~106 cm-3. A differential mobility particle sizer (DMPS) is operated in parallel. We find that SAXS enables measurement of the primary particles and the aggregates, whereas the DMPS detects only aggregates. We conclude that in-situ nanoparticle characterization with ultra-low volume fractions of ~10-10 is feasible with SAXS. Our technique opens up a doorway to the in-situ analysis of aerosol nanoparticles under atmospheric conditions.
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31
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Wei Z, Zhu P, Huang Q. Investigation of ovotransferrin conformation and its complexation with sugar beet pectin. Food Hydrocoll 2019. [DOI: 10.1016/j.foodhyd.2018.08.036] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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32
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Röder K, Joseph JA, Husic BE, Wales DJ. Energy Landscapes for Proteins: From Single Funnels to Multifunctional Systems. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201800175] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Konstantin Röder
- Department of ChemistryUniversity of CambridgeLensfield Road CB2 1EW Cambridge UK
| | - Jerelle A. Joseph
- Department of ChemistryUniversity of CambridgeLensfield Road CB2 1EW Cambridge UK
| | - Brooke E. Husic
- Department of ChemistryUniversity of CambridgeLensfield Road CB2 1EW Cambridge UK
| | - David J. Wales
- Department of ChemistryUniversity of CambridgeLensfield Road CB2 1EW Cambridge UK
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33
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Balu R, Reeder S, Knott R, Mata J, de Campo L, Dutta NK, Choudhury NR. Tough Photocrosslinked Silk Fibroin/Graphene Oxide Nanocomposite Hydrogels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:9238-9251. [PMID: 29989819 DOI: 10.1021/acs.langmuir.8b01141] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The development of protein-based hydrogels for tissue engineering applications is often limited by their mechanical properties. Herein, we present the facile fabrication of tough regenerated silk fibroin (RSF)/graphene oxide (GO) nanocomposite hydrogels by a photochemical cross-linking method. The RSF/GO composite hydrogels demonstrated soft and adhesive properties during initial stages of photocrosslinking (<2 min), which is not observed for the pristine RSF hydrogel, and rendered a tough and nonadhesive hydrogel upon complete cross-linking (10 min). The composite hydrogels exhibited superior tensile mechanical properties, increased β-sheet content, and decreased chain mobility compared to that of the pristine RSF hydrogels. The composite hydrogels demonstrated Young's modulus as high as ∼8 MPa, which is significantly higher than native cartilage (∼1.5 MPa), and tensile toughness as high as ∼2.4 MJ/m3, which is greater than that of electroactive polymer muscles and at par with RSF/GO composite membranes fabricated by layer-by-layer assembly. Small-angle scattering study reveals the hierarchical structure of photocrosslinked RSF hydrogels to comprise randomly distributed water-poor (hydrophobic) and water-rich (hydrophilic) regions at the nanoscale, whereas water pores and channels exhibiting fractal-like characteristics at the microscale. The size of hydrophobic domain (containing β-sheets) was observed to increase slightly with GO incorporation and/or alcohol post-treatment, whereas the size of the hydrophilic domain (intersheet distance containing random coils) was observed to increase significantly, which influences/affects water uptake capacity, cross-link density, and mechanical properties of hydrogels. The presented results have implications for both fundamental understanding of the structure-property relationship of RSF-based hydrogels and their technological applications.
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Affiliation(s)
- Rajkamal Balu
- School of Engineering , RMIT University , Melbourne , Victoria 3001 , Australia
| | - Shaina Reeder
- School of Chemical Engineering , University of Adelaide , Adelaide , South Australia 5005 , Australia
| | - Robert Knott
- Australian Centre for Neutron Scattering , Australian Nuclear Science and Technology Organisation , Sydney , New South Wales 2232 , Australia
| | - Jitendra Mata
- Australian Centre for Neutron Scattering , Australian Nuclear Science and Technology Organisation , Sydney , New South Wales 2232 , Australia
| | - Liliana de Campo
- Australian Centre for Neutron Scattering , Australian Nuclear Science and Technology Organisation , Sydney , New South Wales 2232 , Australia
| | - Naba Kumar Dutta
- School of Engineering , RMIT University , Melbourne , Victoria 3001 , Australia
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34
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Bioinspired, nanoscale approaches in contemporary bioanalytics (Review). Biointerphases 2018; 13:040801. [DOI: 10.1116/1.5037582] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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35
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Whittaker JL, Balu R, Knott R, de Campo L, Mata JP, Rehm C, Hill AJ, Dutta NK, Roy Choudhury N. Structural evolution of photocrosslinked silk fibroin and silk fibroin-based hybrid hydrogels: A small angle and ultra-small angle scattering investigation. Int J Biol Macromol 2018; 114:998-1007. [DOI: 10.1016/j.ijbiomac.2018.03.044] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 03/07/2018] [Accepted: 03/11/2018] [Indexed: 10/17/2022]
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36
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Zettl T, Das R, Harbury PAB, Herschlag D, Lipfert J, Mathew RS, Shi X. Recording and Analyzing Nucleic Acid Distance Distributions with X-Ray Scattering Interferometry (XSI). ACTA ACUST UNITED AC 2018; 73:e54. [PMID: 29927110 DOI: 10.1002/cpnc.54] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Most structural techniques provide averaged information or information about a single predominant conformational state. However, biological macromolecules typically function through series of conformations. Therefore, a complete understanding of macromolecular structures requires knowledge of the ensembles that represent probabilities on a conformational free energy landscape. Here we describe an emerging approach, X-ray scattering interferometry (XSI), a method that provides instantaneous distance distributions for molecules in solution. XSI uses gold nanocrystal labels site-specifically attached to a macromolecule and measures the scattering interference from pairs of heavy metal labels. The recorded signal can directly be transformed into a distance distribution between the two probes. We describe the underlying concepts, present a detailed protocol for preparing samples and recording XSI data, and provide a custom-written graphical user interface to facilitate XSI data analysis. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Thomas Zettl
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, LMU Munich, Munich, Germany.,Department of Biochemistry, Stanford University, Stanford, California
| | - Rhiju Das
- Department of Biochemistry, Stanford University, Stanford, California.,Department of Physics, Stanford University, Stanford, California
| | - Pehr A B Harbury
- Department of Biochemistry, Stanford University, Stanford, California
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University, Stanford, California.,Department of Chemical Engineering, Stanford University, Stanford, California
| | - Jan Lipfert
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, LMU Munich, Munich, Germany
| | - Rebecca S Mathew
- Department of Cell Biology, Harvard Medical School, Harvard University, Boston, Massachusetts
| | - Xuesong Shi
- Department of Biochemistry, Stanford University, Stanford, California
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37
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Cordeiro M, Otrelo-Cardoso AR, Svergun DI, Konarev PV, Lima JC, Santos-Silva T, Baptista PV. Optical and Structural Characterization of a Chronic Myeloid Leukemia DNA Biosensor. ACS Chem Biol 2018; 13:1235-1242. [PMID: 29562136 DOI: 10.1021/acschembio.8b00029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Selective base pairing is the foundation of DNA recognition. Here, we elucidate the molecular and structural details of a FRET-based two-component molecular beacon relying on steady-state fluorescence spectroscopy, small-angle X-ray scattering (SAXS), microscale thermophoresis (MST), and differential electrophoretic mobility. This molecular beacon was designed to detect the most common fusion sequences causing chronic myeloid leukemia, e14a2 and e13a2. The emission spectra indicate that the self-assembly of the different components of the biosensor occurs sequentially, triggered by the fully complementary target. We further assessed the structural alterations leading to the specific fluorescence FRET signature by SAXS, MST, and the differential electrophoretic mobility, where the size range observed is consistent with hybridization and formation of a 1:1:1 complex for the probe in the presence of the complementary target and revelator. These results highlight the importance of different techniques to explore conformational DNA changes in solution and its potential to design and characterize molecular biosensors for genetic disease diagnosis.
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Affiliation(s)
- Mílton Cordeiro
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal
- LAQV, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal
| | - Ana Rita Otrelo-Cardoso
- UCIBIO, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, c/o DESY, Hamburg, Germany, 22067
| | - Petr V. Konarev
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, c/o DESY, Hamburg, Germany, 22067
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics”, Russian Academy of Sciences, Leninsky prospect 59, 119333 Moscow, Russia
- National Research Centre “Kurchatov Institute”, pl. Kurchatova 1, 123182 Moscow, Russia
| | - João Carlos Lima
- LAQV, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal
| | - Teresa Santos-Silva
- UCIBIO, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal
| | - Pedro Viana Baptista
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal
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38
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Zettl T, Mathew RS, Shi X, Doniach S, Herschlag D, Harbury PAB, Lipfert J. Gold nanocrystal labels provide a sequence-to-3D structure map in SAXS reconstructions. SCIENCE ADVANCES 2018; 4:eaar4418. [PMID: 29806025 PMCID: PMC5969820 DOI: 10.1126/sciadv.aar4418] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 04/17/2018] [Indexed: 06/08/2023]
Abstract
Small-angle x-ray scattering (SAXS) is a powerful technique to probe the structure of biological macromolecules and their complexes under virtually arbitrary solution conditions, without the need for crystallization. While it is possible to reconstruct molecular shapes from SAXS data ab initio, the resulting electron density maps have a resolution of ~1 nm and are often insufficient to reliably assign secondary structure elements or domains. We show that SAXS data of gold-labeled samples significantly enhance the information content of SAXS measurements, allowing the unambiguous assignment of macromolecular sequence motifs to specific locations within a SAXS structure. We first demonstrate our approach for site-specifically internally and end-labeled DNA and an RNA motif. In addition, we present a protocol for highly uniform and site-specific labeling of proteins with small (~1.4 nm diameter) gold particles and apply our method to the signaling protein calmodulin. In all cases, the position of the small gold probes can be reliably identified in low-resolution electron density maps. Enhancing low-resolution measurements by site-selective gold labeling provides an attractive approach to aid modeling of a large range of macromolecular systems.
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Affiliation(s)
- Thomas Zettl
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, LMU Munich, Munich, Germany
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
| | - Rebecca S. Mathew
- Department of Cell Biology, Harvard Medical School, Harvard University, Boston, MA 02115, USA
| | - Xuesong Shi
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
| | - Sebastian Doniach
- Departments of Applied Physics and Physics, Stanford University, Stanford, CA 94305, USA
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Pehr A. B. Harbury
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
| | - Jan Lipfert
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, LMU Munich, Munich, Germany
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39
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Bruetzel LK, Walker PU, Gerling T, Dietz H, Lipfert J. Time-Resolved Small-Angle X-ray Scattering Reveals Millisecond Transitions of a DNA Origami Switch. NANO LETTERS 2018; 18:2672-2676. [PMID: 29554806 DOI: 10.1021/acs.nanolett.8b00592] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Self-assembled DNA structures enable creation of specific shapes at the nanometer-micrometer scale with molecular resolution. The construction of functional DNA assemblies will likely require dynamic structures that can undergo controllable conformational changes. DNA devices based on shape complementary stacking interactions have been demonstrated to undergo reversible conformational changes triggered by changes in ionic environment or temperature. An experimentally unexplored aspect is how quickly conformational transitions of large synthetic DNA origami structures can actually occur. Here, we use time-resolved small-angle X-ray scattering to monitor large-scale conformational transitions of a two-state DNA origami switch in free solution. We show that the DNA device switches from its open to its closed conformation upon addition of MgCl2 in milliseconds, which is close to the theoretical diffusive speed limit. In contrast, measurements of the dimerization of DNA origami bricks reveal much slower and concentration-dependent assembly kinetics. DNA brick dimerization occurs on a time scale of minutes to hours suggesting that the kinetics depend on local concentration and molecular alignment.
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Affiliation(s)
- Linda K Bruetzel
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience , LMU Munich , Amalienstrasse 54 , 80799 Munich , Germany
| | - Philipp U Walker
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience , LMU Munich , Amalienstrasse 54 , 80799 Munich , Germany
| | - Thomas Gerling
- Physik Department , Institute for Advanced Study, Technische Universität München , Am Coulombwall 4a , 85748 Garching , Germany
| | - Hendrik Dietz
- Physik Department , Institute for Advanced Study, Technische Universität München , Am Coulombwall 4a , 85748 Garching , Germany
| | - Jan Lipfert
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience , LMU Munich , Amalienstrasse 54 , 80799 Munich , Germany
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40
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Yu S, Kent B, Jafta CJ, Petzold A, Radulescu A, Schuchardt M, Tölle M, van der Giet M, Zidek W, Ballauff M. Stability of human serum albumin structure upon toxin uptake explored by small angle neutron scattering. POLYMER 2018. [DOI: 10.1016/j.polymer.2018.02.060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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41
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Zheng W, Best RB. An Extended Guinier Analysis for Intrinsically Disordered Proteins. J Mol Biol 2018; 430:2540-2553. [PMID: 29571687 DOI: 10.1016/j.jmb.2018.03.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 02/28/2018] [Accepted: 03/12/2018] [Indexed: 12/25/2022]
Abstract
Guinier analysis allows model-free determination of the radius of gyration (Rg) of a biomolecule from X-ray or neutron scattering data, in the limit of very small scattering angles. Its range of validity is well understood for globular proteins, but is known to be more restricted for unfolded or intrinsically disordered proteins (IDPs). We have used ensembles of disordered structures from molecular dynamics simulations to investigate which structural properties cause deviations from the Guinier approximation at small scattering angles. We find that the deviation from the Guinier approximation is correlated with the polymer scaling exponent ν describing the unfolded ensemble. We therefore introduce an empirical, ν-dependent, higher-order correction term, to augment the standard Guinier analysis. We test the new fitting scheme using all-atom simulation data for several IDPs and experimental data for both an IDP and a destabilized mutant of a folded protein. In all cases tested, we achieve an accuracy of the inferred Rg within ∼3% of the true Rg. The method is straightforward to implement and extends the range of validity to a maximum qRg of ∼2 versus ∼1.1 for Guinier analysis. Compared with the Guinier or Debye approaches, our method allows data from wider angles with lower noise to be used to analyze scattering data accurately. In addition to Rg, our fitting scheme also yields estimates of the scaling exponent ν in excellent agreement with the reference ν determined from the underlying molecular ensemble.
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Affiliation(s)
- Wenwei Zheng
- College of Integrative Sciences and Arts, Arizona State University, Mesa, AZ 85212, USA.
| | - Robert B Best
- Laboratory of Chemical Physics, National Institute of Diabetes Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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42
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Ryan TM, Trewhella J, Murphy JM, Keown JR, Casey L, Pearce FG, Goldstone DC, Chen K, Luo Z, Kobe B, McDevitt CA, Watkin SA, Hawley AM, Mudie ST, Samardzic Boban V, Kirby N. An optimized SEC-SAXS system enabling high X-ray dose for rapid SAXS assessment with correlated UV measurements for biomolecular structure analysis. J Appl Crystallogr 2018. [DOI: 10.1107/s1600576717017101] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A new optimized size exclusion chromatography small-angle X-ray scattering (SEC-SAXS) system for biomolecular SAXS at the Australian Synchrotron SAXS/WAXS beamline has been developed. The compact configuration reduces sample dilution to maximize sensitivity. Coflow sample presentation allows an 11-fold increase in flux on sample without capillary fouling, improving throughput and data quality, which are now primarily limited by the full flux available on the beamline. Multi-wavelength fibre optic UV analysis in close proximity to the X-ray beam allows for accurate concentration determination for samples with known UV extinction coefficients and thus estimation of the molecular weight of the scattering particle from the forward X-ray scattering intensity. Fast-flow low-volume SEC columns provide sample throughput competitive with batch concentration series measurements, albeit with a concomitant reduction of potential resolution relative to lower flow rates and larger SEC columns. The performance of the system is demonstrated using a set of model proteins, and its utility to solve various challenges is illustrated with a diverse suite of protein samples. These developments increase the quality and rigor of SEC-SAXS analysis and open new avenues for biomolecular solution SEC-SAXS studies that have been challenged by low sample yields, temporal instability, radiation sensitivity and complex mixtures.
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Harrer N, Schindler CEM, Bruetzel LK, Forné I, Ludwigsen J, Imhof A, Zacharias M, Lipfert J, Mueller-Planitz F. Structural Architecture of the Nucleosome Remodeler ISWI Determined from Cross-Linking, Mass Spectrometry, SAXS, and Modeling. Structure 2018; 26:282-294.e6. [PMID: 29395785 DOI: 10.1016/j.str.2017.12.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 10/25/2017] [Accepted: 12/27/2017] [Indexed: 11/17/2022]
Abstract
Chromatin remodeling factors assume critical roles by regulating access to nucleosomal DNA. To determine the architecture of the Drosophila ISWI remodeling enzyme, we developed an integrative structural approach that combines protein cross-linking, mass spectrometry, small-angle X-ray scattering, and computational modeling. The resulting structural model shows the ATPase module in a resting state with both ATPase lobes twisted against each other, providing support for a conformation that was recently trapped by crystallography. The autoinhibiting NegC region does not protrude from the ATPase module as suggested previously. The regulatory NTR domain is located near both ATPase lobes. The full-length enzyme is flexible and can adopt a compact structure in solution with the C-terminal HSS domain packing against the ATPase module. Our data imply a series of conformational changes upon activation of the enzyme and illustrate how the NTR, NegC, and HSS domains contribute to regulation of the ATPase module.
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Affiliation(s)
- Nadine Harrer
- Molecular Biology, Biomedical Center, Faculty of Medicine, LMU Munich, 82152 Martinsried, Germany
| | - Christina E M Schindler
- Physics Department (T38), Technical University of Munich, 85748 Garching, Germany; Center for Integrated Protein Science Munich, 81377 Munich, Germany
| | - Linda K Bruetzel
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, LMU Munich, 80799 Munich, Germany
| | - Ignasi Forné
- Molecular Biology, Biomedical Center, Faculty of Medicine, LMU Munich, 82152 Martinsried, Germany
| | - Johanna Ludwigsen
- Molecular Biology, Biomedical Center, Faculty of Medicine, LMU Munich, 82152 Martinsried, Germany
| | - Axel Imhof
- Molecular Biology, Biomedical Center, Faculty of Medicine, LMU Munich, 82152 Martinsried, Germany
| | - Martin Zacharias
- Physics Department (T38), Technical University of Munich, 85748 Garching, Germany; Center for Integrated Protein Science Munich, 81377 Munich, Germany
| | - Jan Lipfert
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, LMU Munich, 80799 Munich, Germany.
| | - Felix Mueller-Planitz
- Molecular Biology, Biomedical Center, Faculty of Medicine, LMU Munich, 82152 Martinsried, Germany.
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44
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Ivanović MT, Bruetzel LK, Shevchuk R, Lipfert J, Hub JS. Quantifying the influence of the ion cloud on SAXS profiles of charged proteins. Phys Chem Chem Phys 2018; 20:26351-26361. [DOI: 10.1039/c8cp03080d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
MD simulations and Poisson–Boltzmann calculations predict ion cloud effects on SAXS experiments.
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Affiliation(s)
- Miloš T. Ivanović
- Georg-August-Universität Göttingen, Institute for Microbiology and Genetics
- 37077 Göttingen
- Germany
| | - Linda K. Bruetzel
- Ludwig-Maximilian-Universität München, Department of Physics
- 80799 München
- Germany
| | - Roman Shevchuk
- Georg-August-Universität Göttingen, Institute for Microbiology and Genetics
- 37077 Göttingen
- Germany
| | - Jan Lipfert
- Ludwig-Maximilian-Universität München, Department of Physics
- 80799 München
- Germany
| | - Jochen S. Hub
- Georg-August-Universität Göttingen, Institute for Microbiology and Genetics
- 37077 Göttingen
- Germany
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45
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Harnessing the Combined Power of SAXS and NMR. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1105:171-180. [DOI: 10.1007/978-981-13-2200-6_11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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46
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Yang Y, Wang X, Chen G, Zhou W, Zeng X, Hu B, Li Y, Huang Q. SAXS characterization of the interactions among digested food compounds and the anti-oxidant and anti-inflammatory activities of the formed nanocomplexes. Food Funct 2018; 9:3408-3418. [DOI: 10.1039/c8fo00563j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Small angle X-ray scattering (SAXS) is applied to investigate the interaction between caseinophosphopeptides (CPP) and chitosan (CS) under simulated gastrointestinal (GI) pH conditions.
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Affiliation(s)
- Yingkang Yang
- College of Food Science and Technology
- Nanjing Agricultural University
- Nanjing 210095
- China
| | - Xiaoqi Wang
- Department of Food Science
- Rutgers University
- New Brunswick
- USA
| | - Guijie Chen
- College of Food Science and Technology
- Nanjing Agricultural University
- Nanjing 210095
- China
| | - Wenhua Zhou
- Hunan Key Laboratory of Processed Food for Special Medical Purpose
- Central South University of Forestry and Technology
- Changsha
- China
| | - Xiaoxiong Zeng
- College of Food Science and Technology
- Nanjing Agricultural University
- Nanjing 210095
- China
| | - Bing Hu
- College of Food Science and Technology
- Nanjing Agricultural University
- Nanjing 210095
- China
| | - Yunqi Li
- Key Laboratory of Synthetic Rubber
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun
- P. R. China
| | - Qingrong Huang
- Department of Food Science
- Rutgers University
- New Brunswick
- USA
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47
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Koutsioubas A. Low-Resolution Structure of Detergent-Solubilized Membrane Proteins from Small-Angle Scattering Data. Biophys J 2018; 113:2373-2382. [PMID: 29211991 DOI: 10.1016/j.bpj.2017.10.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 09/20/2017] [Accepted: 10/03/2017] [Indexed: 11/16/2022] Open
Abstract
Despite the ever-increasing usage of small-angle scattering as a valuable complementary method in the field of structural biology, applications concerning membrane proteins remain elusive mainly due to experimental challenges and the relative lack of theoretical tools for the treatment of scattering data. This fact adds up to general difficulties encountered also by other established methods (crystallography, NMR) for the study of membrane proteins. Following the general paradigm of ab initio methods for low-resolution restoration of soluble protein structure from small-angle scattering data, we construct a general multiphase model with a set of physical constraints, which, together with an appropriate minimization procedure, gives direct structural information concerning the different components (protein, detergent molecules) of detergent-solubilized membrane protein complexes. Assessment of the method's precision and robustness is evaluated by performing shape restorations from simulated data of a tetrameric α-helical membrane channel (Aquaporin-0) solubilized by n-Dodecyl β-D-Maltoside and from previously published small-angle neutron scattering experimental data of the filamentous hemagglutinin adhesin β-barrel protein transporter solubilized by n-Octyl β-D-glucopyranoside. It is shown that the acquisition of small-angle neutron scattering data at two different solvent contrasts, together with an estimation of detergent aggregation number around the protein, permits the reliable reconstruction of the shape of membrane proteins without the need for any prior structural information.
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Affiliation(s)
- Alexandros Koutsioubas
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich, Garching, Germany.
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48
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Xu Y, Kuhlmann J, Brennich M, Komorowski K, Jahn R, Steinem C, Salditt T. Reconstitution of SNARE proteins into solid-supported lipid bilayer stacks and X-ray structure analysis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:566-578. [PMID: 29106973 DOI: 10.1016/j.bbamem.2017.10.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 10/01/2017] [Accepted: 10/24/2017] [Indexed: 11/26/2022]
Abstract
SNAREs are known as an important family of proteins mediating vesicle fusion. For various biophysical studies, they have been reconstituted into supported single bilayers via proteoliposome adsorption and rupture. In this study we extended this method to the reconstitution of SNAREs into supported multilamellar lipid membranes, i.e. oriented multibilayer stacks, as an ideal model system for X-ray structure analysis (X-ray reflectivity and diffraction). The reconstitution was implemented through a pathway of proteomicelle, proteoliposome and multibilayer. To monitor the structural evolution in each step, we used small-angle X-ray scattering for the proteomicelles and proteoliposomes, followed by X-ray reflectivity and grazing-incidence small-angle scattering for the multibilayers. Results show that SNAREs can be successfully reconstituted into supported multibilayers, with high enough orientational alignment for the application of surface sensitive X-ray characterizations. Based on this protocol, we then investigated the effect of SNAREs on the structure and phase diagram of the lipid membranes. Beyond this application, this reconstitution protocol could also be useful for X-ray analysis of many further membrane proteins.
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Affiliation(s)
- Yihui Xu
- Institut für Röntgenphysik, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Jan Kuhlmann
- Institut für Organische und Biomolekulare Chemie, Universität Göttingen, Tammannstraße 2, Göttingen 37077, Germany
| | - Martha Brennich
- Structural Biology Group, European Synchrotron Radiation Facility, 71 Avenue des Martyrs, CS 90181, Grenoble 38042, France
| | - Karlo Komorowski
- Institut für Röntgenphysik, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Reinhard Jahn
- Department of Neurobiology, Max-Planck Institute for Biophysical Chemistry, Am Faßberg 11, Göttingen 37077, Germany
| | - Claudia Steinem
- Institut für Organische und Biomolekulare Chemie, Universität Göttingen, Tammannstraße 2, Göttingen 37077, Germany
| | - Tim Salditt
- Institut für Röntgenphysik, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
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49
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Sønderby P, Rinnan Å, Madsen JJ, Harris P, Bukrinski JT, Peters GHJ. Small-Angle X-ray Scattering Data in Combination with RosettaDock Improves the Docking Energy Landscape. J Chem Inf Model 2017; 57:2463-2475. [DOI: 10.1021/acs.jcim.6b00789] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Pernille Sønderby
- Department
of Chemistry, Technical University of Denmark, DK-2800 Kongens
Lyngby, Denmark
| | - Åsmund Rinnan
- Department
of Food Science, Faculty of Science, University of Copenhagen, DK-1958 Frederiksberg C, Denmark
| | - Jesper J. Madsen
- Department
of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Pernille Harris
- Department
of Chemistry, Technical University of Denmark, DK-2800 Kongens
Lyngby, Denmark
| | | | - Günther H. J. Peters
- Department
of Chemistry, Technical University of Denmark, DK-2800 Kongens
Lyngby, Denmark
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50
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Abstract
X-ray scattering is uniquely suited to the study of disordered systems and thus has the potential to provide insight into dynamic processes where diffraction methods fail. In particular, while X-ray crystallography has been a staple of structural biology for more than half a century and will continue to remain so, a major limitation of this technique has been the lack of dynamic information. Solution X-ray scattering has become an invaluable tool in structural and mechanistic studies of biological macromolecules where large conformational changes are involved. Such systems include allosteric enzymes that play key roles in directing metabolic fluxes of biochemical pathways, as well as large, assembly-line type enzymes that synthesize secondary metabolites with pharmaceutical applications. Furthermore, crystallography has the potential to provide information on protein dynamics via the diffuse scattering patterns that are overlaid with Bragg diffraction. Historically, these patterns have been very difficult to interpret, but recent advances in X-ray detection have led to a renewed interest in diffuse scattering analysis as a way to probe correlated motions. Here, we will review X-ray scattering theory and highlight recent advances in scattering-based investigations of protein solutions and crystals, with a particular focus on complex enzymes.
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Affiliation(s)
- Steve P Meisburger
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - William C Thomas
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Maxwell B Watkins
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Nozomi Ando
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
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