1
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Munsayac A, Leite WC, Hopkins JB, Hall I, O’Neill HM, Keane SC. Selective deuteration of an RNA:RNA complex for structural analysis using small-angle scattering. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.09.612093. [PMID: 39314299 PMCID: PMC11419110 DOI: 10.1101/2024.09.09.612093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
The structures of RNA:RNA complexes regulate many biological processes. Despite their importance, protein-free RNA:RNA complexes represent a tiny fraction of experimentally-determined structures. Here, we describe a joint small-angle X-ray and neutron scattering (SAXS/SANS) approach to structurally interrogate conformational changes in a model RNA:RNA complex. Using SAXS, we measured the solution structures of the individual RNAs in their free state and of the overall RNA:RNA complex. With SANS, we demonstrate, as a proof-of-principle, that isotope labeling and contrast matching (CM) can be combined to probe the bound state structure of an RNA within a selectively deuterated RNA:RNA complex. Furthermore, we show that experimental scattering data can validate and improve predicted AlphaFold 3 RNA:RNA complex structures to reflect its solution structure. Our work demonstrates that in silico modeling, SAXS, and CM-SANS can be used in concert to directly analyze conformational changes within RNAs when in complex, enhancing our understanding of RNA structure in functional assemblies.
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Affiliation(s)
- Aldrex Munsayac
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Wellington C. Leite
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Jesse B. Hopkins
- The Biophysics Collaborative Access Team (BioCAT), Department of Physics, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Ian Hall
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Hugh M. O’Neill
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Sarah C. Keane
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
- Biophysics Program, University of Michigan, Ann Arbor, MI, 48109, USA
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2
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Grabner D, Pickett PD, McAfee T, Collins BA. Molecular Weight-Independent "Polysoap" Nanostructure Characterized via In Situ Resonant Soft X-ray Scattering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:7444-7455. [PMID: 38552143 DOI: 10.1021/acs.langmuir.3c03897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
Studying polymer micelle structure and loading dynamics under environmental conditions is critical for nanocarrier applications but challenging due to a lack of in situ nanoprobes. Here, the structure and loading of amphiphilic polyelectrolyte copolymer micelles, formed by 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and n-dodecyl acrylamide (DDAM), were investigated using a multimodal approach centered around in situ resonant soft X-ray scattering (RSoXS). We observe aqueous micelles formed from polymers of wide-ranging molecular weights and aqueous concentrations. Despite no measurable critical micelle concentration (CMC), structural analyses point toward multimeric structures for most molecular weights, with the lowest molecular weight micelles containing mixed coronas and forming loose micelle clusters that enhance hydrocarbon uptake. The sizes of the micelle substructures are independent of both the concentration and molecular weight. Combining these results with a measured molecular weight-invariant surface charge and zeta potential strengthens the link between the nanoparticle size and ionic charge in solution that governs the polysoap micelle structure. Such control would be critical for nanocarrier applications, such as drug delivery and water remediation.
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Affiliation(s)
- Devin Grabner
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, United States
| | - Phillip D Pickett
- School of Polymer Science and Engineering, University of Southern Mississippi, Hattiesburg, Mississippi 39406, United States
| | - Terry McAfee
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, United States
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Brian A Collins
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, United States
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3
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Dao HM, AboulFotouh K, Hussain AF, Marras AE, Johnston KP, Cui Z, Williams RO. Characterization of mRNA Lipid Nanoparticles by Electron Density Mapping Reconstruction: X-ray Scattering with Density from Solution Scattering (DENSS) Algorithm. Pharm Res 2024; 41:501-512. [PMID: 38326530 DOI: 10.1007/s11095-024-03671-9] [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: 09/27/2023] [Accepted: 01/28/2024] [Indexed: 02/09/2024]
Abstract
PURPOSE This study aimed to test the feasibility of using Small Angle X-ray Scattering (SAXS) coupled with Density from Solution Scattering (DENSS) algorithm to characterize the internal architecture of messenger RNA-containing lipid nanoparticles (mRNA-LNPs). METHODS The DENSS algorithm was employed to construct a three-dimensional model of average individual mRNA-LNP. The reconstructed models were cross validated with cryogenic transmission electron microscopy (cryo-TEM), and dynamic light scattering (DLS) to assess size, morphology, and internal structure. RESULTS Cryo-TEM and DLS complemented SAXS, revealed a core-shell mRNA-LNP structure with electron-rich mRNA-rich region at the core, surrounded by lipids. The reconstructed model, utilizing the DENSS algorithm, effectively distinguishes mRNA and lipids via electron density mapping. Notably, DENSS accurately models the morphology of the mRNA-LNPs as an ellipsoidal shape with a "bleb" architecture or a two-compartment structure with contrasting electron densities, corresponding to mRNA-filled and empty lipid compartments, respectively. Finally, subtle changes in the LNP structure after three freeze-thaw cycles were detected by SAXS, demonstrating an increase in radius of gyration (Rg) associated with mRNA leakage. CONCLUSION Analyzing SAXS profiles based on DENSS algorithm to yield a reconstructed electron density based three-dimensional model can be a useful physicochemical characterization method in the toolbox to study mRNA-LNPs and facilitate their development.
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Affiliation(s)
- Huy M Dao
- Division of Molecular Pharmaceutics and Drug Delivery, College of Pharmacy, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Khaled AboulFotouh
- Division of Molecular Pharmaceutics and Drug Delivery, College of Pharmacy, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Aasim Faheem Hussain
- Department of Biomedical Engineering, Cockrell School of Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Alexander E Marras
- Department of Biomedical Engineering, Cockrell School of Engineering, The University of Texas at Austin, Austin, TX, USA
- Materials Science and Engineering Graduate Program, Texas Materials Institute, The University of Texas at Austin, Austin, TX, USA
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Keith P Johnston
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Zhengrong Cui
- Division of Molecular Pharmaceutics and Drug Delivery, College of Pharmacy, The University of Texas at Austin, Austin, TX, 78712, USA.
| | - Robert O Williams
- Division of Molecular Pharmaceutics and Drug Delivery, College of Pharmacy, The University of Texas at Austin, Austin, TX, 78712, USA.
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4
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Hajizadeh M, Golub M, Moldenhauer M, Matsarskaia O, Martel A, Porcar L, Maksimov E, Friedrich T, Pieper J. Solution Structures of Two Different FRP-OCP Complexes as Revealed via SEC-SANS. Int J Mol Sci 2024; 25:2781. [PMID: 38474026 DOI: 10.3390/ijms25052781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 02/02/2024] [Accepted: 02/21/2024] [Indexed: 03/14/2024] Open
Abstract
Photosynthetic organisms have established photoprotective mechanisms in order to dissipate excess light energy into heat, which is commonly known as non-photochemical quenching. Cyanobacteria utilize the orange carotenoid protein (OCP) as a high-light sensor and quencher to regulate the energy flow in the photosynthetic apparatus. Triggered by strong light, OCP undergoes conformational changes to form the active red state (OCPR). In many cyanobacteria, the back conversion of OCP to the dark-adapted state is assisted by the fluorescence recovery protein (FRP). However, the exact molecular events involving OCP and its interaction with FRP remain largely unraveled so far due to their metastability. Here, we use small-angle neutron scattering combined with size exclusion chromatography (SEC-SANS) to unravel the solution structures of FRP-OCP complexes using a compact mutant of OCP lacking the N-terminal extension (∆NTEOCPO) and wild-type FRP. The results are consistent with the simultaneous presence of stable 2:2 and 2:1 FRP-∆NTEOCPO complexes in solution, where the former complex type is observed for the first time. For both complex types, we provide ab initio low-resolution shape reconstructions and compare them to homology models based on available crystal structures. It is likely that both complexes represent intermediate states of the back conversion of OCP to its dark-adapted state in the presence of FRP, which are of transient nature in the photocycle of wild-type OCP. This study demonstrates the large potential of SEC-SANS in revealing the solution structures of protein complexes in polydisperse solutions that would otherwise be averaged, leading to unspecific results.
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Affiliation(s)
- Mina Hajizadeh
- Institute of Physics, University of Tartu, W. Ostwald Str. 1, 50411 Tartu, Estonia
| | - Maksym Golub
- Institute of Physics, University of Tartu, W. Ostwald Str. 1, 50411 Tartu, Estonia
| | - Marcus Moldenhauer
- Institute of Chemistry PC 14, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Olga Matsarskaia
- Institut Laue-Langevin, Avenue des Martyrs 71, CEDEX 9, 38042 Grenoble, France
| | - Anne Martel
- Institut Laue-Langevin, Avenue des Martyrs 71, CEDEX 9, 38042 Grenoble, France
| | - Lionel Porcar
- Institut Laue-Langevin, Avenue des Martyrs 71, CEDEX 9, 38042 Grenoble, France
| | - Eugene Maksimov
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119991 Moscow, Russia
| | - Thomas Friedrich
- Institute of Chemistry PC 14, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Jörg Pieper
- Institute of Physics, University of Tartu, W. Ostwald Str. 1, 50411 Tartu, Estonia
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5
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Sonje J, Thakral S, Krueger S, Suryanarayanan R. Enabling Efficient Design of Biological Formulations Through Advanced Characterization. Pharm Res 2023; 40:1459-1477. [PMID: 36959413 DOI: 10.1007/s11095-023-03495-z] [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: 11/23/2022] [Accepted: 03/01/2023] [Indexed: 03/25/2023]
Abstract
The present review summarizes the use of differential scanning calorimetry (DSC) and scattering techniques in the context of protein formulation design and characterization. The scattering techniques include wide angle X-ray diffractometry (XRD), small-angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS). While DSC is valuable for understanding thermal behavior of the excipients, XRD provides critical information about physical state of solutes during freezing, annealing and in the final lyophile. However, as these techniques lack the sensitivity to detect biomolecule-related transitions, complementary characterization techniques such as small-angle scattering can provide valuable insights.
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Affiliation(s)
- Jayesh Sonje
- Department of Pharmaceutics, College of Pharmacy, University of Minnesota, 308 Harvard St. SE, Minneapolis, MN, 55455, USA
- BioTherapeutics, Pharmaceutical Sciences, Pfizer Inc., 1 Burtt Road, Andover, USA
| | - Seema Thakral
- Boehringer Ingelheim Pharmaceuticals, Inc, 900 Ridgebury Road, Ridgefield, CT, 06877, USA
| | - Susan Krueger
- Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, USA
- Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742, USA
| | - Raj Suryanarayanan
- Department of Pharmaceutics, College of Pharmacy, University of Minnesota, 308 Harvard St. SE, Minneapolis, MN, 55455, USA.
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6
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Morishima K, Inoue R, Sugiyama M. Derivation of the small-angle scattering profile of a target biomacromolecule from a profile deteriorated by aggregates. AUC-SAS. J Appl Crystallogr 2023; 56:624-632. [PMID: 37284265 PMCID: PMC10241049 DOI: 10.1107/s1600576723002406] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 03/12/2023] [Indexed: 06/08/2023] Open
Abstract
Aggregates cause a fatal problem in the structural analysis of a biomacro-mol-ecule in solution using small-angle X-ray or neutron scattering (SAS): they deteriorate the scattering profile of the target molecule and lead to an incorrect structure. Recently, an integrated method of analytical ultracentrifugation (AUC) and SAS, abbreviated AUC-SAS, was developed as a new approach to overcome this problem. However, the original version of AUC-SAS does not offer a correct scattering profile of the target molecule when the weight fraction of aggregates is higher than ca 10%. In this study, the obstacle point in the original AUC-SAS approach is identified. The improved AUC-SAS method is then applicable to a solution with a relatively larger weight fraction of aggregates (≤20%).
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Affiliation(s)
- Ken Morishima
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2-1010 Asashironishi, Kumatori, Sennan-gun, Osaka 590-0494, Japan
| | - Rintaro Inoue
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2-1010 Asashironishi, Kumatori, Sennan-gun, Osaka 590-0494, Japan
| | - Masaaki Sugiyama
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2-1010 Asashironishi, Kumatori, Sennan-gun, Osaka 590-0494, Japan
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7
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Haubrich K, Spiteri VA, Farnaby W, Sobott F, Ciulli A. Breaking free from the crystal lattice: Structural biology in solution to study protein degraders. Curr Opin Struct Biol 2023; 79:102534. [PMID: 36804675 DOI: 10.1016/j.sbi.2023.102534] [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: 10/23/2022] [Revised: 12/15/2022] [Accepted: 01/06/2023] [Indexed: 02/17/2023]
Abstract
Structural biology offers a versatile arsenal of techniques and methods to investigate the structure and conformational dynamics of proteins and their assemblies. The growing field of targeted protein degradation centres on the premise of developing small molecules, termed degraders, to induce proximity between an E3 ligase and a protein of interest to be signalled for degradation. This new drug modality brings with it new opportunities and challenges to structural biologists. Here we discuss how several structural biology techniques, including nuclear magnetic resonance, cryo-electron microscopy, structural mass spectrometry and small angle scattering, have been explored to complement X-ray crystallography in studying degraders and their ternary complexes. Together the studies covered in this review make a case for the invaluable perspectives that integrative structural biology techniques in solution can bring to understanding ternary complexes and designing degraders.
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Affiliation(s)
- Kevin Haubrich
- Centre for Targeted Protein Degradation & Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK. https://twitter.com/KevinHaubrich1
| | - Valentina A Spiteri
- Centre for Targeted Protein Degradation & Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK. https://twitter.com/val_spiteri
| | - William Farnaby
- Centre for Targeted Protein Degradation & Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK. https://twitter.com/farnaby84
| | - Frank Sobott
- School of Molecular and Cellular Biology & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK. https://twitter.com/FrankSobott
| | - Alessio Ciulli
- Centre for Targeted Protein Degradation & Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK.
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8
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Data quality assurance, model validation, and data sharing for biomolecular structures from small-angle scattering. Methods Enzymol 2022; 678:1-22. [PMID: 36641205 DOI: 10.1016/bs.mie.2022.11.002] [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: 12/14/2022]
Abstract
Key to small-angle scattering (SAS) maturing and becoming a mainstream structural biology technique was the work done by the SAS community to establish standards for data quality, model validation and data sharing. Through a consultative process spanning more than a decade and a half, guidelines for publication have been established that include criteria for evaluating data quality and for model validation. In this process gaps were identified that stimulated innovation and development of new tools, for example new measures of model ambiguity and of the goodness-of-fit of a model to SAS data that complement the traditional global fit parameter χ2. The need for a global repository for biomolecular SAS data and models was identified and the SASBDB was established as a searchable, curated, freely accessible, downloadable database of experimental data, experimental conditions, sample details, derived models, and their fit to the data. Importantly, the SASBDB uses a common dictionary format that supports archiving of structures solved using integrative methods to support seamless data exchange with a federated system of public databanks that includes the world-wide Protein Data Bank (wwPDB) as the major repository for structural biology. Thus, biomolecular SAS is now well-positioned to achieve its full potential as a mainstream structural biology technique contributing at the frontier of integrative structural biology and meeting "best practice" standards for data quality assurance and data sharing.
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9
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Barnsley LC, Nandakumaran N, Feoktystov A, Dulle M, Fruhner L, Feygenson M. A reverse Monte Carlo algorithm to simulate two-dimensional small-angle scattering intensities. J Appl Crystallogr 2022; 55:1592-1602. [PMID: 36570657 PMCID: PMC9721324 DOI: 10.1107/s1600576722009219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 09/16/2022] [Indexed: 11/30/2022] Open
Abstract
Small-angle scattering (SAS) experiments are a powerful method for studying self-assembly phenomena in nanoscopic materials because of the sensitivity of the technique to structures formed by interactions on the nanoscale. Numerous out-of-the-box options exist for analysing structures measured by SAS but many of these are underpinned by assumptions about the underlying interactions that are not always relevant for a given system. Here, a numerical algorithm based on reverse Monte Carlo simulations is described to model the intensity observed on a SAS detector as a function of the scattering vector. The model simulates a two-dimensional detector image, accounting for magnetic scattering, instrument resolution, particle polydispersity and particle collisions, while making no further assumptions about the underlying particle interactions. By simulating a two-dimensional image that can be potentially anisotropic, the algorithm is particularly useful for studying systems driven by anisotropic interactions. The final output of the algorithm is a relative particle distribution, allowing visualization of particle structures that form over long-range length scales (i.e. several hundred nanometres), along with an orientational distribution of magnetic moments. The effectiveness of the algorithm is shown by modelling a SAS experimental data set studying finite-length chains consisting of magnetic nanoparticles, which assembled in the presence of a strong magnetic field due to dipole interactions.
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Affiliation(s)
- Lester C. Barnsley
- Australian Synchrotron, ANSTO, Clayton 3168, Australia,Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85748 Garching, Germany,Correspondence e-mail:
| | - Nileena Nandakumaran
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-2) and Peter Grünberg Institut (PGI), JARA-FIT, 52425 Jülich, Germany,Lehrstuhl für Experimentalphysik IVc, RWTH Aachen University, 52056 Aachen, Germany
| | - Artem Feoktystov
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85748 Garching, Germany
| | - Martin Dulle
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1), 52425 Jülich, Germany
| | - Lisa Fruhner
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1), 52425 Jülich, Germany
| | - Mikhail Feygenson
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1), 52425 Jülich, Germany,European Spallation Source ERIC, SE-22100 Lund, Sweden
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10
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Sun Y, Li X, Chen R, Liu F, Wei S. Recent advances in structural characterization of biomacromolecules in foods via small-angle X-ray scattering. Front Nutr 2022; 9:1039762. [PMID: 36466419 PMCID: PMC9714470 DOI: 10.3389/fnut.2022.1039762] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/03/2022] [Indexed: 08/04/2023] Open
Abstract
Small-angle X-ray scattering (SAXS) is a method for examining the solution structure, oligomeric state, conformational changes, and flexibility of biomacromolecules at a scale ranging from a few Angstroms to hundreds of nanometers. Wide time scales ranging from real time (milliseconds) to minutes can be also covered by SAXS. With many advantages, SAXS has been extensively used, it is widely used in the structural characterization of biomacromolecules in food science and technology. However, the application of SAXS in charactering the structure of food biomacromolecules has not been reviewed so far. In the current review, the principle, theoretical calculations and modeling programs are summarized, technical advances in the experimental setups and corresponding applications of in situ capabilities: combination of chromatography, time-resolved, temperature, pressure, flow-through are elaborated. Recent applications of SAXS for monitoring structural properties of biomacromolecules in food including protein, carbohydrate and lipid are also highlighted, and limitations and prospects for developing SAXS based on facility upgraded and artificial intelligence to study the structural properties of biomacromolecules are finally discussed. Future research should focus on extending machine time, simplifying SAXS data treatment, optimizing modeling methods in order to achieve an integrated structural biology based on SAXS as a practical tool for investigating the structure-function relationship of biomacromolecules in food industry.
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Affiliation(s)
- Yang Sun
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, China
| | - Xiujuan Li
- Pharmaceutical Department, The Affiliated Taian City Central Hospital of Qingdao University, Taian, China
| | - Ruixin Chen
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, China
| | - Fei Liu
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, China
| | - Song Wei
- Tumor Precise Intervention and Translational Medicine Laboratory, The Affiliated Taian City Central Hospital of Qingdao University, Taian, China
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11
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Observing protein degradation in solution by the PAN-20S proteasome complex: Astate-of-the-art example of bio-macromolecular TR-SANS. Methods Enzymol 2022; 678:97-120. [PMID: 36641218 DOI: 10.1016/bs.mie.2022.09.016] [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: 11/09/2022]
Abstract
In the present book chapter we illustrate the state-of-the-art of time-resolved small-angle neutron scattering (TR-SANS) by a concrete example of a dynamic bio-macromolecular system, i.e., regulated protein degradation by the archaeal PAN-20S proteasome complex. We present the specific and unique structural information that can be obtained by this approach, in combination with bio-macromolecular deuteration and online spectrophotometric measurements of a fluorescent substrate (GFP). The complementarity with atomic-resolution structural biology techniques (SAXS, NMR, crystallography and cryo-EM) and with the advent of atomic structure prediction are discussed, as well as the respective limitations and future perspectives.
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12
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Delhommel F, Martínez-Lumbreras S, Sattler M. Combining NMR, SAXS and SANS to characterize the structure and dynamics of protein complexes. Methods Enzymol 2022; 678:263-297. [PMID: 36641211 DOI: 10.1016/bs.mie.2022.09.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Understanding the structure and dynamics of biological macromolecules is essential to decipher the molecular mechanisms that underlie cellular functions. The description of structure and conformational dynamics often requires the integration of complementary techniques. In this review, we highlight the utility of combining nuclear magnetic resonance (NMR) spectroscopy with small angle scattering (SAS) to characterize these challenging biomolecular systems. NMR can assess the structure and conformational dynamics of multidomain proteins, RNAs and biomolecular complexes. It can efficiently provide information on interaction surfaces, long-distance restraints and relative domain orientations at residue-level resolution. Such information can be readily combined with high-resolution structural data available on subcomponents of biomolecular assemblies. Moreover, NMR is a powerful tool to characterize the dynamics of biomolecules on a wide range of timescales, from nanoseconds to seconds. On the other hand, SAS approaches provide global information on the size and shape of biomolecules and on the ensemble of all conformations present in solution. Therefore, NMR and SAS provide complementary data that are uniquely suited to investigate dynamic biomolecular assemblies. Here, we briefly review the type of data that can be obtained by both techniques and describe different approaches that can be used to combine them to characterize biomolecular assemblies. We then provide guidelines on which experiments are best suited depending on the type of system studied, ranging from fully rigid complexes, dynamic structures that interconvert between defined conformations and systems with very high structural heterogeneity.
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Affiliation(s)
- Florent Delhommel
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany; Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching, Germany
| | - Santiago Martínez-Lumbreras
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany; Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching, Germany
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany; Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching, Germany.
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13
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Trewhella J, Vachette P, Bierma J, Blanchet C, Brookes E, Chakravarthy S, Chatzimagas L, Cleveland TE, Cowieson N, Crossett B, Duff AP, Franke D, Gabel F, Gillilan RE, Graewert M, Grishaev A, Guss JM, Hammel M, Hopkins J, Huang Q, Hub JS, Hura GL, Irving TC, Jeffries CM, Jeong C, Kirby N, Krueger S, Martel A, Matsui T, Li N, Pérez J, Porcar L, Prangé T, Rajkovic I, Rocco M, Rosenberg DJ, Ryan TM, Seifert S, Sekiguchi H, Svergun D, Teixeira S, Thureau A, Weiss TM, Whitten AE, Wood K, Zuo X. A round-robin approach provides a detailed assessment of biomolecular small-angle scattering data reproducibility and yields consensus curves for benchmarking. Acta Crystallogr D Struct Biol 2022; 78:1315-1336. [PMID: 36322416 PMCID: PMC9629491 DOI: 10.1107/s2059798322009184] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 09/15/2022] [Indexed: 12/14/2022] Open
Abstract
Through an expansive international effort that involved data collection on 12 small-angle X-ray scattering (SAXS) and four small-angle neutron scattering (SANS) instruments, 171 SAXS and 76 SANS measurements for five proteins (ribonuclease A, lysozyme, xylanase, urate oxidase and xylose isomerase) were acquired. From these data, the solvent-subtracted protein scattering profiles were shown to be reproducible, with the caveat that an additive constant adjustment was required to account for small errors in solvent subtraction. Further, the major features of the obtained consensus SAXS data over the q measurement range 0-1 Å-1 are consistent with theoretical prediction. The inherently lower statistical precision for SANS limited the reliably measured q-range to <0.5 Å-1, but within the limits of experimental uncertainties the major features of the consensus SANS data were also consistent with prediction for all five proteins measured in H2O and in D2O. Thus, a foundation set of consensus SAS profiles has been obtained for benchmarking scattering-profile prediction from atomic coordinates. Additionally, two sets of SAXS data measured at different facilities to q > 2.2 Å-1 showed good mutual agreement, affirming that this region has interpretable features for structural modelling. SAS measurements with inline size-exclusion chromatography (SEC) proved to be generally superior for eliminating sample heterogeneity, but with unavoidable sample dilution during column elution, while batch SAS data collected at higher concentrations and for longer times provided superior statistical precision. Careful merging of data measured using inline SEC and batch modes, or low- and high-concentration data from batch measurements, was successful in eliminating small amounts of aggregate or interparticle interference from the scattering while providing improved statistical precision overall for the benchmarking data set.
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Affiliation(s)
- Jill Trewhella
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Patrice Vachette
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Paris, 91198 Gif-sur-Yvette, France
| | - Jan Bierma
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Clement Blanchet
- European Molecular Biology Laboratory (EMBL) Hamburg Unit, Notkestrasse 85, c/o Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
| | - Emre Brookes
- Chemistry and Biochemistry, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA
| | - Srinivas Chakravarthy
- BioCAT, Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Leonie Chatzimagas
- Theoretical Physics and Center for Biophysics, Saarland University, Campus E2.6, 66123 Saarbrücken, Germany
| | - Thomas E. Cleveland
- Institute for Bioscience and Biotechnology Research, 9600 Gudelsky Drive, Rockville, MD 20850, USA
- National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - Nathan Cowieson
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Ben Crossett
- Sydney Mass Spectrometry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Anthony P. Duff
- Australian Nuclear Science and Technology Organisation, New Illawara Road, Lucas Heights, NSW 2234, Australia
| | - Daniel Franke
- European Molecular Biology Laboratory (EMBL) Hamburg Unit, Notkestrasse 85, c/o Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
| | - Frank Gabel
- Institut de Biologie Structurale, CEA, CNRS, Université Grenoblé Alpes, 41 Rue Jules Horowitz, 38027 Grenoble, France
| | - Richard E. Gillilan
- Cornell High-Energy Synchrotron Source, 161 Synchrotron Drive, Ithaca, NY 14853, USA
| | - Melissa Graewert
- European Molecular Biology Laboratory (EMBL) Hamburg Unit, Notkestrasse 85, c/o Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
| | - Alexander Grishaev
- Institute for Bioscience and Biotechnology Research, 9600 Gudelsky Drive, Rockville, MD 20850, USA
- National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - J. Mitchell Guss
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Michal Hammel
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Jesse Hopkins
- BioCAT, Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Qingqui Huang
- Cornell High-Energy Synchrotron Source, 161 Synchrotron Drive, Ithaca, NY 14853, USA
| | - Jochen S. Hub
- Theoretical Physics and Center for Biophysics, Saarland University, Campus E2.6, 66123 Saarbrücken, Germany
| | - Greg L. Hura
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Thomas C. Irving
- BioCAT, Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Cy Michael Jeffries
- European Molecular Biology Laboratory (EMBL) Hamburg Unit, Notkestrasse 85, c/o Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
| | - Cheol Jeong
- Department of Physics, Wesleyan University, Middletown, CT 06459, USA
| | - Nigel Kirby
- Australian Synchrotron, ANSTO, 800 Blackburn Road, Clayton, VIC 3158, Australia
| | - Susan Krueger
- National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - Anne Martel
- Institut Laue–Langevin, 71 Avenue des Martyrs, 38042 Grenoble CEDEX 9, France
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Lightsource, Stanford University, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Na Li
- National Facility for Protein Science in Shanghai, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Road No. 333, Haike Road, Shanghai 201210, People’s Republic of China
| | - Javier Pérez
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin BP 48, 91192 Gif-sur-Yvette, France
| | - Lionel Porcar
- Institut Laue–Langevin, 71 Avenue des Martyrs, 38042 Grenoble CEDEX 9, France
| | - Thierry Prangé
- CITCoM (UMR 8038 CNRS), Faculté de Pharmacie, 4 Avenue de l’Observatoire, 75006 Paris, France
| | - Ivan Rajkovic
- Stanford Synchrotron Radiation Lightsource, Stanford University, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Mattia Rocco
- Proteomica e Spettrometria di Massa, IRCCS Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132 Genova, Italy
| | - Daniel J. Rosenberg
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Timothy M. Ryan
- Australian Synchrotron, ANSTO, 800 Blackburn Road, Clayton, VIC 3158, Australia
| | - Soenke Seifert
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Hiroshi Sekiguchi
- SPring-8, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyōgo 679-5198, Japan
| | - Dmitri Svergun
- European Molecular Biology Laboratory (EMBL) Hamburg Unit, Notkestrasse 85, c/o Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
| | - Susana Teixeira
- National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, DE 19716, USA
| | - Aurelien Thureau
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin BP 48, 91192 Gif-sur-Yvette, France
| | - Thomas M. Weiss
- Stanford Synchrotron Radiation Lightsource, Stanford University, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Andrew E. Whitten
- Australian Nuclear Science and Technology Organisation, New Illawara Road, Lucas Heights, NSW 2234, Australia
| | - Kathleen Wood
- Australian Nuclear Science and Technology Organisation, New Illawara Road, Lucas Heights, NSW 2234, Australia
| | - Xiaobing Zuo
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
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14
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Whitten AE, Jeffries CM. Data analysis and modeling of small-angle neutron scattering data with contrast variation from bio-macromolecular complexes. Methods Enzymol 2022; 678:55-96. [PMID: 36641217 DOI: 10.1016/bs.mie.2022.09.015] [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: 11/11/2022]
Abstract
Small-angle neutron scattering (SANS) with contrast variation (CV) is a valuable technique in the structural biology toolchest. Accurate structural parameters-e.g., radii of gyration, volumes, dimensions, and distance distribution(s)-can be derived from the SANS-CV data to yield the shape and disposition of the individual components within stable complexes. Contrast variation is achieved through the substitution of hydrogen isotopes (1H for 2H) in molecules and solvents to alter the neutron scattering properties of each component of a complex. While SANS-CV can be used a stand-alone technique for interrogating the overall structure of biomacromolecules in solution, it also complements other methods such as small-angle X-ray scattering, crystallography, nuclear magnetic resonance, and cryo-electron microscopy. Undertaking a SANS-CV experiment is challenging, due in part to the preparation of significant quantities of monodisperse samples that may require deuterium (2H) labeling. Nevertheless, SANS-CV can be used to study a diverse range biomacromolecular complexes including protein-protein and protein-nucleic acid systems, membrane proteins, and flexible systems resistant to crystallization. This chapter describes how to approach the data analysis and modeling of SANS data, including: (1) Analysis of the forward scattering (I(0)) and calculation of theoretical estimates of contrast; (2) Analysis of the contrast dependence of the radius of gyration using the Stuhrmann plot and parallel axis theorem; (3) Calculation of composite scattering functions to evaluate the size, shape, and dispositions of individual components within a complex, and; (4) Development of real-space models to fit the SANS-CV data using volume-element bead modeling or atomistic rigid body modeling.
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Affiliation(s)
- Andrew E Whitten
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, Australia.
| | - Cy M Jeffries
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, c/o Deutsches Elektronen-Synchrotron, Hamburg, Germany.
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15
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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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16
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Anitas EM. α-SAS: an integrative approach for structural modeling of biological macromolecules in solution. Acta Crystallogr D Struct Biol 2022; 78:1046-1063. [DOI: 10.1107/s2059798322006349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 06/16/2022] [Indexed: 11/10/2022] Open
Abstract
Modern small-angle scattering (SAS) experiments with neutrons (SANS) or X-rays (SAXS) combined with contrast variation provide comprehensive information about the structure of large multicomponent macromolecules in solution and allow the size, shape and relative arrangement of each component to be mapped out. To obtain such information, it is essential to perform well designed experiments, in which all necessary steps, from assessing sample suitability to structure modeling, are properly executed. This paper describes α-SAS, an integrative approach that is useful for effectively planning a biological contrast-variation SAS experiment. The accurate generation of expected experimental intensities using α-SAS allows the substantial acceleratation of research into the structure and function of biomacromolecules by minimizing the time and costs associated with performing a SAS experiment. The method is validated using a few basic structures with known analytical expressions for scattering intensity and using experimental SAXS data from Arabidopsis β-amylase 1 protein and SANS data from the histidine kinase–Sda complex and from human dystrophin without and with a membrane-mimicking nanodisk. Simulation of a SANS contrast-variation experiment is performed for synthetic nanobodies that effectively neutralize SARS-CoV-2.
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17
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Krueger S. Small-angle neutron scattering contrast variation studies of biological complexes: Challenges and triumphs. Curr Opin Struct Biol 2022; 74:102375. [PMID: 35490650 PMCID: PMC10988784 DOI: 10.1016/j.sbi.2022.102375] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/09/2022] [Accepted: 03/22/2022] [Indexed: 11/16/2022]
Abstract
Small-angle neutron scattering (SANS) has been a beneficial tool for studying the structure of biological macromolecules in solution for several decades. Continued improvements in sample preparation techniques, including deuterium labeling, neutron instrumentation and complementary techniques such as small-angle x-ray scattering (SAXS), cryo-EM, NMR and x-ray crystallography, along with the availability of more powerful structure prediction algorithms and computational resources has made SANS more important than ever as a means to obtain unique information on the structure of biological complexes in solution. In particular, the contrast variation (CV) technique, which requires a large commitment in both sample preparation and measurement time, has become more practical with the advent of these improved resources. Here, challenges and recent triumphs as well as future prospects are discussed.
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Affiliation(s)
- Susan Krueger
- NIST Center for Neutron Research, NIST, Gaithersburg, MD, 20899, USA.
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18
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Lakey JH, Paracini N, Clifton LA. Exploiting neutron scattering contrast variation in biological membrane studies. BIOPHYSICS REVIEWS 2022; 3:021307. [PMID: 38505417 PMCID: PMC10903484 DOI: 10.1063/5.0091372] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 05/03/2022] [Indexed: 03/21/2024]
Abstract
Biological membranes composed of lipids and proteins are central for the function of all cells and individual components, such as proteins, that are readily studied by a range of structural approaches, including x-ray crystallography and cryo-electron microscopy. However, the study of complex molecular mixtures within the biological membrane structure and dynamics requires techniques that can study nanometer thick molecular bilayers in an aqueous environment at ambient temperature and pressure. Neutron methods, including scattering and spectroscopic approaches, are useful since they can measure structure and dynamics while also being able to penetrate sample holders and cuvettes. The structural approaches, such as small angle neutron scattering and neutron reflectometry, detect scattering caused by the difference in neutron contrast (scattering length) between different molecular components such as lipids or proteins. Usually, the bigger the contrast, the clearer the structural data, and this review uses examples from our research to illustrate how contrast can be increased to allow the structures of individual membrane components to be resolved. Most often this relies upon the use of deuterium in place of hydrogen, but we also discuss the use of magnetic contrast and other elements with useful scattering length values.
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Affiliation(s)
- Jeremy H. Lakey
- Institute for Cell and Molecular Bioscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Nicolò Paracini
- Biofilms Research Center for Biointerfaces, Malmö University, Per Albin Hanssons väg 35, 21432 Malmö, Sweden
| | - Luke A. Clifton
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
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19
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Benedetto A, Kelley EG. Absorption of the [bmim][Cl] Ionic Liquid in DMPC Lipid Bilayers across Their Gel, Ripple, and Fluid Phases. J Phys Chem B 2022; 126:3309-3318. [PMID: 35472281 PMCID: PMC9082605 DOI: 10.1021/acs.jpcb.2c00710] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 04/11/2022] [Indexed: 12/19/2022]
Abstract
Lipid bilayers are a key component of cell membranes and play a crucial role in life and in bio-nanotechnology. As a result, controlling their physicochemical properties holds the promise of effective therapeutic strategies. Ionic liquids (ILs)─a vast class of complex organic electrolytes─have shown a high degree of affinity with lipid bilayers and can be exploited in this context. However, the chemical physics of IL absorption and partitioning into lipid bilayers is yet to be fully understood. This work focuses on the absorption of the model IL [bmim][Cl] into 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayers across their gel, ripple, and fluid phases. Here, by small-angle neutron scattering, we show that (i) the IL cations are absorbed in the lipid bilayer in all its thermodynamic phases and (ii) the amount of IL inserted into the lipid phase increased with increasing temperature, changing from three to four IL cations per 10 lipids with increasing temperature from 10 °C in the gel phase to 40 °C in the liquid phase, respectively. An explicative hypothesis, based on the entropy gain coming from the IL hydration water, is presented to explain the observed temperature trend. The ability to control IL absorption with temperature can be used as a handle to tune the effect of ILs on biomembranes and can be exploited in bio-nanotechnological applications.
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Affiliation(s)
- Antonio Benedetto
- Department
of Science, University of Roma Tre, 00146 Rome, Italy
- School
of Physics, and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
- Laboratory
for Neutron Scattering, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Elizabeth G. Kelley
- NIST
Center for Neutron Research, National Institute
of Standards and Technology, Gaithersburg, Maryland 20899, United States
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20
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Tominaga T, Nakagawa H, Sahara M, Oda T, Inoue R, Sugiyama M. Data Collection for Dilute Protein Solutions via a Neutron Backscattering Spectrometer. Life (Basel) 2022; 12:life12050675. [PMID: 35629343 PMCID: PMC9145923 DOI: 10.3390/life12050675] [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: 03/17/2022] [Revised: 04/12/2022] [Accepted: 04/29/2022] [Indexed: 11/16/2022] Open
Abstract
Understanding protein functions requires not only static but also dynamic structural information. Incoherent quasi-elastic neutron scattering (QENS), which utilizes the highly incoherent scattering ability of hydrogen, is a powerful technique for revealing the dynamics of proteins in deuterium oxide (D2O) buffer solutions. The background scattering of sample cells suitable for aqueous protein solution samples, conducted with a neutron backscattering spectrometer, was evaluated. It was found that the scattering intensity of an aluminum sample cell coated with boehmite using D2O was lower than that of a sample cell coated with regular water (H2O). The D2O-Boehmite coated cell was used for the QENS measurement of a 0.8 wt.% aqueous solution of an intrinsically disordered protein in an intrinsically disordered region of a helicase-associated endonuclease for a fork-structured type of DNA. The cell was inert against aqueous samples at 283–363 K. In addition, meticulous attention to cells with small individual weight differences and the positional reproducibility of the sample cell relative to the spectrometer neutron beam position enabled the accurate subtraction of the scattering profiles of the D2O buffer and the sample container. Consequently, high-quality information on protein dynamics could be extracted from dilute protein solutions.
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Affiliation(s)
- Taiki Tominaga
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), 162-1 Shirakata, Ibaraki 319-1106, Japan;
- Correspondence:
| | - Hiroshi Nakagawa
- Materials Sciences Research Center, Japan Atomic Energy Agency, Ibaraki 319-1195, Japan;
- J-PARC Center, Japan Atomic Energy Agency, Ibaraki 319-1195, Japan
| | - Masae Sahara
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), 162-1 Shirakata, Ibaraki 319-1106, Japan;
| | - Takashi Oda
- Department of Life Science, Rikkyo University, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan;
| | - Rintaro Inoue
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Kumatori, Sennan-gun, Osaka 590-0494, Japan; (R.I.); (M.S.)
| | - Masaaki Sugiyama
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Kumatori, Sennan-gun, Osaka 590-0494, Japan; (R.I.); (M.S.)
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21
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Trewhella J. Recent advances in small-angle scattering and its expanding impact in structural biology. Structure 2022; 30:15-23. [PMID: 34995477 DOI: 10.1016/j.str.2021.09.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/23/2021] [Accepted: 09/20/2021] [Indexed: 10/19/2022]
Abstract
Applications of small-angle scattering (SAS) in structural biology have benefited from continuing developments in instrumentation, tools for data analysis, modeling capabilities, standards for data and model presentation, and data archiving. The interplay of these capabilities has enabled SAS to contribute to advances in structural biology as the field pushes the boundaries in studies of biomolecular complexes and assemblies as large as whole cells, membrane proteins in lipid environments, and dynamic systems on time scales ranging from femtoseconds to hours. This review covers some of the important advances in biomolecular SAS capabilities for structural biology focused on over the last 5 years and presents highlights of recent applications that demonstrate how the technique is exploring new territories.
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Affiliation(s)
- Jill Trewhella
- School of Life and Environmental Sciences, The University of Sydney, Camperdown, NSW 2006, Australia.
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22
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Martel A, Gabel F. Time-resolved small-angle neutron scattering (TR-SANS) for structural biology of dynamic systems: Principles, recent developments, and practical guidelines. Methods Enzymol 2022; 677:263-290. [DOI: 10.1016/bs.mie.2022.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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23
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Krueger S. Planning, executing and assessing the validity of SANS contrast variation experiments. Methods Enzymol 2022; 677:127-155. [DOI: 10.1016/bs.mie.2022.08.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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24
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Josts I, Kehlenbeck DM, Nitsche J, Tidow H. Studying integral membrane protein by SANS using stealth reconstitution systems. Methods Enzymol 2022; 677:417-432. [DOI: 10.1016/bs.mie.2022.08.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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25
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Pietras Z, Wood K, Whitten AE, Jeffries CM. Technical considerations for small-angle neutron scattering from biological macromolecules in solution: Cross sections, contrasts, instrument setup and measurement. Methods Enzymol 2022; 677:157-189. [DOI: 10.1016/bs.mie.2022.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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26
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Morrison KA, Doekhie A, Neville GM, Price GJ, Whitley P, Doutch J, Edler KJ. Ab initio reconstruction of small angle scattering data for membrane proteins in copolymer nanodiscs. BBA ADVANCES 2021; 2:100033. [PMID: 37082608 PMCID: PMC10074903 DOI: 10.1016/j.bbadva.2021.100033] [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: 11/16/2022] Open
Abstract
Background Small angle scattering techniques are beginning to be more widely utilised for structural analysis of biological systems. However, applying these techniques to study membrane proteins still remains problematic, due to sample preparation requirements and analysis of the resulting data. The development of styrene-maleic acid co-polymers (SMA) to extract membrane proteins into nanodiscs for further study provides a suitable environment for structural analysis. Methods We use small angle neutron scattering (SANS) with three different contrasts to determine structural information for two different polymer nanodisc-incorporated proteins, Outer membrane protein F (OmpF) and gramicidin. Ab initio modelling was applied to generate protein/lipid structures from the SANS data. Other complementary structural methodologies, such as DLS, CD and TEM were compared alongside this data with known protein crystal structures. Results A single-phase model was constructed for gramicidin-containing nanodiscs, which showed dimer formation in the centre of the nanodisc. For OmpF-nanodiscs we were able to construct a multi-phase model, providing structural information on the protein/lipid and polymer components of the sample. Conclusions Polymer-nanodiscs can provide a suitable platform to investigate certain membrane proteins using SANS, alongside other structural methodologies. However, differences between the published crystal structure and OmpF-nanodiscs were observed, suggesting the nanodisc structure could be altering the folding of the protein. General significance Small angle scattering techniques can provide structural information on the protein and polymer nanodisc without requiring crystallisation of the protein. Additional complementary techniques, such as ab initio modelling, can generate alternative models both the protein and nanodisc system.
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Affiliation(s)
- Kerrie A. Morrison
- Department of Chemistry, University of Bath, Bath, UK
- Department of Biology and Biochemistry, University of Bath, Bath, UK
- Centre for Sustainable and Circular Technologies, University of Bath, Bath, UK
| | - Aswin Doekhie
- Department of Chemistry, University of Bath, Bath, UK
| | - George M. Neville
- Department of Chemistry, University of Bath, Bath, UK
- Centre for Sustainable and Circular Technologies, University of Bath, Bath, UK
| | - Gareth J. Price
- Department of Chemistry, University of Bath, Bath, UK
- Department of Chemistry, Khalifa University, Abu Dhabi, UAE
| | - Paul Whitley
- Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - James Doutch
- ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX. UK
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Perez-Salas U, Garg S, Gerelli Y, Porcar L. Deciphering lipid transfer between and within membranes with time-resolved small-angle neutron scattering. CURRENT TOPICS IN MEMBRANES 2021; 88:359-412. [PMID: 34862031 DOI: 10.1016/bs.ctm.2021.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This review focuses on time-resolved neutron scattering, particularly time-resolved small angle neutron scattering (TR-SANS), as a powerful in situ noninvasive technique to investigate intra- and intermembrane transport and distribution of lipids and sterols in lipid membranes. In contrast to using molecular analogues with potentially large chemical tags that can significantly alter transport properties, small angle neutron scattering relies on the relative amounts of the two most abundant isotope forms of hydrogen: protium and deuterium to detect complex membrane architectures and transport processes unambiguously. This review discusses advances in our understanding of the mechanisms that sustain lipid asymmetry in membranes-a key feature of the plasma membrane of cells-as well as the transport of lipids between membranes, which is an essential metabolic process.
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Affiliation(s)
- Ursula Perez-Salas
- Physics Department, University of Illinois at Chicago, Chicago, IL, United States.
| | - Sumit Garg
- Physics Department, University of Illinois at Chicago, Chicago, IL, United States
| | - Yuri Gerelli
- Department of Life and Environmental Sciences, Universita` Politecnica delle Marche, Ancona, Italy
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28
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Tsegaye S, Dedefo G, Mehdi M. Biophysical applications in structural and molecular biology. Biol Chem 2021; 402:1155-1177. [PMID: 34218543 DOI: 10.1515/hsz-2021-0232] [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: 04/15/2021] [Accepted: 05/27/2021] [Indexed: 11/15/2022]
Abstract
The main objective of structural biology is to model proteins and other biological macromolecules and link the structural information to function and dynamics. The biological functions of protein molecules and nucleic acids are inherently dependent on their conformational dynamics. Imaging of individual molecules and their dynamic characteristics is an ample source of knowledge that brings new insights about mechanisms of action. The atomic-resolution structural information on most of the biomolecules has been solved by biophysical techniques; either by X-ray diffraction in single crystals or by nuclear magnetic resonance (NMR) spectroscopy in solution. Cryo-electron microscopy (cryo-EM) is emerging as a new tool for analysis of a larger macromolecule that couldn't be solved by X-ray crystallography or NMR. Now a day's low-resolution Cryo-EM is used in combination with either X-ray crystallography or NMR. The present review intends to provide updated information on applications like X-ray crystallography, cryo-EM and NMR which can be used independently and/or together in solving structures of biological macromolecules for our full comprehension of their biological mechanisms.
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Affiliation(s)
- Solomon Tsegaye
- Department of Biochemistry, College of Health Sciences, Arsi University, Oromia, Ethiopia
| | - Gobena Dedefo
- Department of Medical Laboratory Technology, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Mohammed Mehdi
- Department of Biochemistry, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
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29
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Zooming in on protein-RNA interactions: a multi-level workflow to identify interaction partners. Biochem Soc Trans 2021; 48:1529-1543. [PMID: 32820806 PMCID: PMC7458403 DOI: 10.1042/bst20191059] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 02/01/2023]
Abstract
Interactions between proteins and RNA are at the base of numerous cellular regulatory and functional phenomena. The investigation of the biological relevance of non-coding RNAs has led to the identification of numerous novel RNA-binding proteins (RBPs). However, defining the RNA sequences and structures that are selectively recognised by an RBP remains challenging, since these interactions can be transient and highly dynamic, and may be mediated by unstructured regions in the protein, as in the case of many non-canonical RBPs. Numerous experimental and computational methodologies have been developed to predict, identify and verify the binding between a given RBP and potential RNA partners, but navigating across the vast ocean of data can be frustrating and misleading. In this mini-review, we propose a workflow for the identification of the RNA binding partners of putative, newly identified RBPs. The large pool of potential binders selected by in-cell experiments can be enriched by in silico tools such as catRAPID, which is able to predict the RNA sequences more likely to interact with specific RBP regions with high accuracy. The RNA candidates with the highest potential can then be analysed in vitro to determine the binding strength and to precisely identify the binding sites. The results thus obtained can furthermore validate the computational predictions, offering an all-round solution to the issue of finding the most likely RNA binding partners for a newly identified potential RBP.
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30
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The mitochondrial ADP/ATP carrier exists and functions as a monomer. Biochem Soc Trans 2021; 48:1419-1432. [PMID: 32725219 PMCID: PMC7458400 DOI: 10.1042/bst20190933] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/26/2020] [Accepted: 07/06/2020] [Indexed: 12/15/2022]
Abstract
For more than 40 years, the oligomeric state of members of the mitochondrial carrier family (SLC25) has been the subject of debate. Initially, the consensus was that they were dimeric, based on the application of a large number of different techniques. However, the structures of the mitochondrial ADP/ATP carrier, a member of the family, clearly demonstrated that its structural fold is monomeric, lacking a conserved dimerisation interface. A re-evaluation of previously published data, with the advantage of hindsight, concluded that technical errors were at the basis of the earlier dimer claims. Here, we revisit this topic, as new claims for the existence of dimers of the bovine ADP/ATP carrier have emerged using native mass spectrometry of mitochondrial membrane vesicles. However, the measured mass does not agree with previously published values, and a large number of post-translational modifications are proposed to account for the difference. Contrarily, these modifications are not observed in electron density maps of the bovine carrier. If they were present, they would interfere with the structure and function of the carrier, including inhibitor and substrate binding. Furthermore, the reported mass does not account for three tightly bound cardiolipin molecules, which are consistently observed in other studies and are important stabilising factors for the transport mechanism. The monomeric carrier has all of the required properties for a functional transporter and undergoes large conformational changes that are incompatible with a stable dimerisation interface. Thus, our view that the native mitochondrial ADP/ATP carrier exists and functions as a monomer remains unaltered.
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31
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McAfee T, Ferron T, Cordova IA, Pickett PD, McCormick CL, Wang C, Collins BA. Label-free characterization of organic nanocarriers reveals persistent single molecule cores for hydrocarbon sequestration. Nat Commun 2021; 12:3123. [PMID: 34035289 PMCID: PMC8149835 DOI: 10.1038/s41467-021-23382-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 04/23/2021] [Indexed: 02/04/2023] Open
Abstract
Self-assembled molecular nanostructures embody an enormous potential for new technologies, therapeutics, and understanding of molecular biofunctions. Their structure and function are dependent on local environments, necessitating in-situ/operando investigations for the biggest leaps in discovery and design. However, the most advanced of such investigations involve laborious labeling methods that can disrupt behavior or are not fast enough to capture stimuli-responsive phenomena. We utilize X-rays resonant with molecular bonds to demonstrate an in-situ nanoprobe that eliminates the need for labels and enables data collection times within seconds. Our analytical spectral model quantifies the structure, molecular composition, and dynamics of a copolymer micelle drug delivery platform using resonant soft X-rays. We additionally apply this technique to a hydrocarbon sequestrating polysoap micelle and discover that the critical organic-capturing domain does not coalesce upon aggregation but retains distinct single-molecule cores. This characteristic promotes its efficiency of hydrocarbon sequestration for applications like oil spill remediation and drug delivery. Such a technique enables operando, chemically sensitive investigations of any aqueous molecular nanostructure, label-free.
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Affiliation(s)
- Terry McAfee
- grid.30064.310000 0001 2157 6568Department of Physics and Astronomy, Washington State University, Pullman, WA USA ,grid.184769.50000 0001 2231 4551Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, NC USA
| | - Thomas Ferron
- grid.30064.310000 0001 2157 6568Department of Physics and Astronomy, Washington State University, Pullman, WA USA
| | - Isvar A. Cordova
- grid.184769.50000 0001 2231 4551Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, NC USA
| | - Phillip D. Pickett
- grid.267193.80000 0001 2295 628XSchool of Polymer Science and Engineering, University of Southern Mississippi, Hattiesburg, MS USA
| | - Charles L. McCormick
- grid.267193.80000 0001 2295 628XSchool of Polymer Science and Engineering, University of Southern Mississippi, Hattiesburg, MS USA
| | - Cheng Wang
- grid.184769.50000 0001 2231 4551Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, NC USA
| | - Brian A. Collins
- grid.30064.310000 0001 2157 6568Department of Physics and Astronomy, Washington State University, Pullman, WA USA
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Matsuo T. Viewing SARS-CoV-2 Nucleocapsid Protein in Terms of Molecular Flexibility. BIOLOGY 2021; 10:454. [PMID: 34064163 PMCID: PMC8224284 DOI: 10.3390/biology10060454] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/18/2021] [Accepted: 05/18/2021] [Indexed: 12/23/2022]
Abstract
The latest coronavirus SARS-CoV-2, which causes coronavirus disease 2019 (COVID-19) pneumonia leading to the pandemic, contains 29 proteins. Among them, nucleocapsid protein (NCoV2) is one of the abundant proteins and shows multiple functions including packaging the RNA genome during the infection cycle. It has also emerged as a potential drug target. In this review, the current status of the research of NCoV2 is described in terms of molecular structure and dynamics. NCoV2 consists of two domains, i.e., the N-terminal domain (NTD) and the C-terminal domain (CTD) with a disordered region between them. Recent simulation studies have identified several potential drugs that can bind to NTD or CTD with high affinity. Moreover, it was shown that the degree of flexibility in the disordered region has a large effect on drug binding rate, suggesting the importance of molecular flexibility for the NCoV2 function. Molecular flexibility has also been shown to be integral to the formation of droplets, where NCoV2, RNA and/or other viral proteins gather through liquid-liquid phase separation and considered important for viral replication. Finally, as one of the future research directions, a strategy for obtaining the structural and dynamical information on the proteins contained in droplets is presented.
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Affiliation(s)
- Tatsuhito Matsuo
- Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology, 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1106, Japan;
- Laboratoire Interdisciplinaire de Physique (LiPhy), Grenoble-Alpes University, 140 Rue de la Physique, 38402 Saint Martin d’Hères, France
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, CEDEX 9, 38042 Grenoble, France
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33
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Semeraro EF, Marx L, Frewein MPK, Pabst G. Increasing complexity in small-angle X-ray and neutron scattering experiments: from biological membrane mimics to live cells. SOFT MATTER 2021; 17:222-232. [PMID: 32104874 DOI: 10.1039/c9sm02352f] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Small-angle X-ray and neutron scattering are well-established, non-invasive experimental techniques to interrogate global structural properties of biological membrane mimicking systems under physiologically relevant conditions. Recent developments, both in bottom-up sample preparation techniques for increasingly complex model systems, and in data analysis techniques have opened the path toward addressing long standing issues of biological membrane remodelling processes. These efforts also include emerging quantitative scattering studies on live cells, thus enabling a bridging of molecular to cellular length scales. Here, we review recent progress in devising compositional models for joint small-angle X-ray and neutron scattering studies on diverse membrane mimics - with a specific focus on membrane structural coupling to amphiphatic peptides and integral proteins - and live Escherichia coli. In particular, we outline the present state-of-the-art in small-angle scattering methods applied to complex membrane systems, highlighting how increasing system complexity must be followed by an advance in compositional modelling and data-analysis tools.
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Affiliation(s)
- Enrico F Semeraro
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, 8010 Graz, Austria. and BioTechMed Graz, 8010 Graz, Austria
| | - Lisa Marx
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, 8010 Graz, Austria. and BioTechMed Graz, 8010 Graz, Austria
| | - Moritz P K Frewein
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, 8010 Graz, Austria. and BioTechMed Graz, 8010 Graz, Austria and Institut Laue-Langevin, 38000 Grenoble, France
| | - Georg Pabst
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, 8010 Graz, Austria. and BioTechMed Graz, 8010 Graz, Austria
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34
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Ziegler SJ, Mallinson SJ, St. John PC, Bomble YJ. Advances in integrative structural biology: Towards understanding protein complexes in their cellular context. Comput Struct Biotechnol J 2020; 19:214-225. [PMID: 33425253 PMCID: PMC7772369 DOI: 10.1016/j.csbj.2020.11.052] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 11/25/2020] [Accepted: 11/28/2020] [Indexed: 01/26/2023] Open
Abstract
Microorganisms rely on protein interactions to transmit signals, react to stimuli, and grow. One of the best ways to understand these protein interactions is through structural characterization. However, in the past, structural knowledge was limited to stable, high-affinity complexes that could be crystallized. Recent developments in structural biology have revolutionized how protein interactions are characterized. The combination of multiple techniques, known as integrative structural biology, has provided insight into how large protein complexes interact in their native environment. In this mini-review, we describe the past, present, and potential future of integrative structural biology as a tool for characterizing protein interactions in their cellular context.
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Key Words
- CLEM, correlated light and electron microscopy
- Crosslinking mass spectrometry
- Cryo-electron microscopy
- Cryo-electron tomography
- EPR, electron paramagnetic resonance
- FRET, Forster resonance energy transfer
- ISB, Integrative structural biology
- Integrative structural biology
- ML, machine learning
- MR, molecular replacement
- MSAs, multiple sequence alignments
- MX, macromolecular crystallography
- NMR, nuclear magnetic resonance
- PDB, Protein Data Bank
- Protein docking
- Protein structure prediction
- Quinary interactions
- SAD, single-wavelength anomalous dispersion
- SANS, small angle neutron scattering
- SAXS, small angle X-ray scattering
- X-ray crystallography
- XL-MS, cross-linking mass spectrometry
- cryo-EM SPA, cryo-EM single particle analysis
- cryo-EM, cryo-electron microscopy
- cryo-ET, cryo-electron tomography
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Affiliation(s)
- Samantha J. Ziegler
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Sam J.B. Mallinson
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Peter C. St. John
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Yannick J. Bomble
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
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Agarwal PK, Bernard DN, Bafna K, Doucet N. Enzyme dynamics: Looking beyond a single structure. ChemCatChem 2020; 12:4704-4720. [PMID: 33897908 PMCID: PMC8064270 DOI: 10.1002/cctc.202000665] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Indexed: 12/23/2022]
Abstract
Conventional understanding of how enzymes function strongly emphasizes the role of structure. However, increasing evidence clearly indicates that enzymes do not remain fixed or operate exclusively in or close to their native structure. Different parts of the enzyme (from individual residues to full domains) undergo concerted motions on a wide range of time-scales, including that of the catalyzed reaction. Information obtained on these internal motions and conformational fluctuations has so far uncovered and explained many aspects of enzyme mechanisms, which could not have been understood from a single structure alone. Although there is wide interest in understanding enzyme dynamics and its role in catalysis, several challenges remain. In addition to technical difficulties, the vast majority of investigations are performed in dilute aqueous solutions, where conditions are significantly different than the cellular milieu where a large number of enzymes operate. In this review, we discuss recent developments, several challenges as well as opportunities related to this topic. The benefits of considering dynamics as an integral part of the enzyme function can also enable new means of biocatalysis, engineering enzymes for industrial and medicinal applications.
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Affiliation(s)
- Pratul K. Agarwal
- Department of Physiological Sciences and High-Performance Computing Center, Oklahoma State University, Stillwater, Oklahoma 74078
- Arium BioLabs, 2519 Caspian Drive, Knoxville, Tennessee 37932
| | - David N. Bernard
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique (INRS), Université du Québec, 531 Boulevard des Prairies, Laval, Quebec, H7V 1B7, Canada
| | - Khushboo Bafna
- Department of Chemistry and Chemical Biology, and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Nicolas Doucet
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique (INRS), Université du Québec, 531 Boulevard des Prairies, Laval, Quebec, H7V 1B7, Canada
- PROTEO, the Quebec Network for Research on Protein Function, Structure, and Engineering, 1045 Avenue de la Médecine, Université Laval, Québec, QC, G1V 0A6, Canada
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36
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Ünnep R, Paul S, Zsiros O, Kovács L, Székely NK, Steinbach G, Appavou MS, Porcar L, Holzwarth AR, Garab G, Nagy G. Thylakoid membrane reorganizations revealed by small-angle neutron scattering of Monstera deliciosa leaves associated with non-photochemical quenching. Open Biol 2020; 10:200144. [PMID: 32931722 PMCID: PMC7536078 DOI: 10.1098/rsob.200144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/14/2020] [Indexed: 12/14/2022] Open
Abstract
Non-photochemical quenching (NPQ) is an important photoprotective mechanism in plants and algae. Although the process is extensively studied, little is known about its relationship with ultrastructural changes of the thylakoid membranes. In order to better understand this relationship, we studied the effects of illumination on the organization of thylakoid membranes in Monstera deliciosa leaves. This evergreen species is known to exhibit very large NPQ and to possess giant grana with dozens of stacked thylakoids. It is thus ideally suited for small-angle neutron scattering measurements (SANS)-a non-invasive technique, which is capable of providing spatially and statistically averaged information on the periodicity of the thylakoid membranes and their rapid reorganizations in vivo. We show that NPQ-inducing illumination causes a strong decrease in the periodic order of granum thylakoid membranes. Development of NPQ and light-induced ultrastructural changes, as well as the relaxation processes, follow similar kinetic patterns. Surprisingly, whereas NPQ is suppressed by diuron, it impedes only the relaxation of the structural changes and not its formation, suggesting that structural changes do not cause but enable NPQ. We also demonstrate that the diminishment of SANS peak does not originate from light-induced redistribution and reorientation of chloroplasts inside the cells.
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Affiliation(s)
- Renáta Ünnep
- Neutron Spectroscopy Department, Centre for Energy Research, H-1121 Budapest, Konkoly-Thege Miklós út 29-33, Hungary
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Suman Paul
- Max-Planck-Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim a.d. Ruhr, Germany
| | - Ottó Zsiros
- Biological Research Centre, Institute of Plant Biology, 6726 Szeged, Hungary
| | - László Kovács
- Biological Research Centre, Institute of Plant Biology, 6726 Szeged, Hungary
| | - Noémi K. Székely
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, 85748 Garching, Germany
| | - Gábor Steinbach
- Biological Research Centre, Institute of Biophysics, Temesvári körút 62, 6726 Szeged, Hungary
| | - Marie-Sousai Appavou
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, 85748 Garching, Germany
| | - Lionel Porcar
- Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9, France
| | - Alfred R. Holzwarth
- Max-Planck-Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim a.d. Ruhr, Germany
| | - Győző Garab
- Biological Research Centre, Institute of Plant Biology, 6726 Szeged, Hungary
- Department of Physics, Faculty of Science, Ostrava University, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Gergely Nagy
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- European Spallation Source ESS ERIC, PO Box 176, 221 00 Lund, Sweden
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, 1121 Budapest, Hungary
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De Hoe GX, Mao J, Jiang Z, Darling SB, Tirrell MV, Chen W. Probing Diffuse Polymer Brush Interfaces Using Resonant Soft X-ray Scattering. ACTA ACUST UNITED AC 2020. [DOI: 10.1080/08940886.2020.1784698] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Guilhem X. De Hoe
- Advanced Materials for Energy-Water Systems Center and Center for Molecular Engineering, Argonne National Laboratory, Lemont, Illinois, USA
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois, USA
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois, USA
| | - Jun Mao
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois, USA
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois, USA
| | - Zhang Jiang
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois, USA
| | - Seth B. Darling
- Advanced Materials for Energy-Water Systems Center and Center for Molecular Engineering, Argonne National Laboratory, Lemont, Illinois, USA
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois, USA
| | - Matthew V. Tirrell
- Advanced Materials for Energy-Water Systems Center and Center for Molecular Engineering, Argonne National Laboratory, Lemont, Illinois, USA
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois, USA
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois, USA
| | - Wei Chen
- Advanced Materials for Energy-Water Systems Center and Center for Molecular Engineering, Argonne National Laboratory, Lemont, Illinois, USA
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois, USA
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois, USA
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Pounot K, Chaaban H, Foderà V, Schirò G, Weik M, Seydel T. Tracking Internal and Global Diffusive Dynamics During Protein Aggregation by High-Resolution Neutron Spectroscopy. J Phys Chem Lett 2020; 11:6299-6304. [PMID: 32663030 DOI: 10.1021/acs.jpclett.0c01530] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Proteins can misfold and form either amorphous or organized aggregates with different morphologies and features. Aggregates of amyloid nature are pathological hallmarks in so-called protein conformational diseases, including Alzheimer's and Parkinson's. Evidence prevails that the transient early phases of the reaction determine the aggregate morphology and toxicity. As a consequence, real-time monitoring of protein aggregation is of utmost importance. Here, we employed time-resolved neutron backscattering spectroscopy to follow center-of-mass self-diffusion and nano- to picosecond internal dynamics of lysozyme during aggregation into a specific β-sheet rich superstructure, called particulates, formed at the isoelectric point of the protein. Particulate formation is found to be a one-step process, and protein internal dynamics, to remain unchanged during the entire aggregation process. The time-resolved neutron backscattering spectroscopy approach developed here, in combination with standard kinetics assays, provides a unifying framework in which dynamics and conformational transitions can be related to the different aggregation pathways.
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Affiliation(s)
- Kevin Pounot
- Université Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000 Grenoble, France
- Institut Max von Laue - Paul Langevin, 71 avenue des Martyrs, CS 20156, F-38042 Grenoble cedex 9, France
| | - Hussein Chaaban
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Vito Foderà
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Giorgio Schirò
- Université Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000 Grenoble, France
| | - Martin Weik
- Université Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000 Grenoble, France
| | - Tilo Seydel
- Institut Max von Laue - Paul Langevin, 71 avenue des Martyrs, CS 20156, F-38042 Grenoble cedex 9, France
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39
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Jeffries CM, Pietras Z, Svergun DI. The basics of small-angle neutron scattering (SANS for new users of structural biology). EPJ WEB OF CONFERENCES 2020. [DOI: 10.1051/epjconf/202023603001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Small-angle neutron scattering (SANS) provides a means to probe the time-preserved structural state(s) of bio-macromolecules in solution. As such, SANS affords the opportunity to assess the redistribution of mass, i.e., changes in conformation, which occur when macromolecules interact to form higher-order assemblies and to evaluate the structure and disposition of components within such systems. As a technique, SANS offers scope for ‘out of the box thinking’, from simply investigating the structures of macromolecules and their complexes through to where structural biology interfaces with soft-matter and nanotechnology. All of this simply rests on the way neutrons interact and scatter from atoms (largely hydrogens) and how this interaction differs from the scattering of neutrons from the nuclei of other ‘biological isotopes’. The following chapter describes the basics of neutron scattering for new users of structural biology in context of the neutron/hydrogen interaction and how this can be exploited to interrogate the structures of macromolecules, their complexes and nano-conjugates in solution.
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40
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Mahieu E, Covès J, Krüger G, Martel A, Moulin M, Carl N, Härtlein M, Carlomagno T, Franzetti B, Gabel F. Observing Protein Degradation by the PAN-20S Proteasome by Time-Resolved Neutron Scattering. Biophys J 2020; 119:375-388. [PMID: 32640186 PMCID: PMC7376118 DOI: 10.1016/j.bpj.2020.06.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 06/05/2020] [Accepted: 06/09/2020] [Indexed: 12/21/2022] Open
Abstract
The proteasome is a key player of regulated protein degradation in all kingdoms of life. Although recent atomic structures have provided snapshots on a number of conformations, data on substrate states and populations during the active degradation process in solution remain scarce. Here, we use time-resolved small-angle neutron scattering of a deuterium-labeled GFPssrA substrate and an unlabeled archaeal PAN-20S system to obtain direct structural information on substrate states during ATP-driven unfolding and subsequent proteolysis in solution. We find that native GFPssrA structures are degraded in a biexponential process, which correlates strongly with ATP hydrolysis, the loss of fluorescence, and the buildup of small oligopeptide products. Our solution structural data support a model in which the substrate is directly translocated from PAN into the 20S proteolytic chamber, after a first, to our knowledge, successful unfolding process that represents a point of no return and thus prevents dissociation of the complex and the release of harmful, aggregation-prone products.
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Affiliation(s)
- Emilie Mahieu
- University Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Jacques Covès
- University Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Georg Krüger
- Leibniz University Hannover, Centre for Biomolecular Drug Research, Hannover, Germany
| | | | | | - Nico Carl
- Institut Laue-Langevin, Grenoble, France
| | | | - Teresa Carlomagno
- Leibniz University Hannover, Centre for Biomolecular Drug Research, Hannover, Germany; Group of Structural Chemistry, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | | | - Frank Gabel
- University Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France; Institut Laue-Langevin, Grenoble, France.
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41
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Delhommel F, Gabel F, Sattler M. Current approaches for integrating solution NMR spectroscopy and small-angle scattering to study the structure and dynamics of biomolecular complexes. J Mol Biol 2020; 432:2890-2912. [DOI: 10.1016/j.jmb.2020.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/27/2020] [Accepted: 03/10/2020] [Indexed: 01/24/2023]
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42
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Larsen AH, Wang Y, Bottaro S, Grudinin S, Arleth L, Lindorff-Larsen K. Combining molecular dynamics simulations with small-angle X-ray and neutron scattering data to study multi-domain proteins in solution. PLoS Comput Biol 2020; 16:e1007870. [PMID: 32339173 PMCID: PMC7205321 DOI: 10.1371/journal.pcbi.1007870] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 05/07/2020] [Accepted: 04/13/2020] [Indexed: 11/18/2022] Open
Abstract
Many proteins contain multiple folded domains separated by flexible linkers, and the ability to describe the structure and conformational heterogeneity of such flexible systems pushes the limits of structural biology. Using the three-domain protein TIA-1 as an example, we here combine coarse-grained molecular dynamics simulations with previously measured small-angle scattering data to study the conformation of TIA-1 in solution. We show that while the coarse-grained potential (Martini) in itself leads to too compact conformations, increasing the strength of protein-water interactions results in ensembles that are in very good agreement with experiments. We show how these ensembles can be refined further using a Bayesian/Maximum Entropy approach, and examine the robustness to errors in the energy function. In particular we find that as long as the initial simulation is relatively good, reweighting against experiments is very robust. We also study the relative information in X-ray and neutron scattering experiments and find that refining against the SAXS experiments leads to improvement in the SANS data. Our results suggest a general strategy for studying the conformation of multi-domain proteins in solution that combines coarse-grained simulations with small-angle X-ray scattering data that are generally most easy to obtain. These results may in turn be used to design further small-angle neutron scattering experiments that exploit contrast variation through 1H/2H isotope substitutions.
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Affiliation(s)
- Andreas Haahr Larsen
- Structural Biology and NMR Laboratory, Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- X-ray and Neutron Science, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Yong Wang
- Structural Biology and NMR Laboratory, Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Sandro Bottaro
- Structural Biology and NMR Laboratory, Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Sergei Grudinin
- Univ. Grenoble Alpes, CNRS, Inria, Grenoble INP, LJK, Grenoble, France
| | - Lise Arleth
- X-ray and Neutron Science, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory, Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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43
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Zaccaria M, Dawson W, Cristiglio V, Reverberi M, Ratcliff LE, Nakajima T, Genovese L, Momeni B. Designing a bioremediator: mechanistic models guide cellular and molecular specialization. Curr Opin Biotechnol 2020; 62:98-105. [DOI: 10.1016/j.copbio.2019.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/22/2019] [Accepted: 09/06/2019] [Indexed: 12/26/2022]
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Malanovic N, Marx L, Blondelle SE, Pabst G, Semeraro EF. Experimental concepts for linking the biological activities of antimicrobial peptides to their molecular modes of action. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183275. [PMID: 32173291 DOI: 10.1016/j.bbamem.2020.183275] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/09/2020] [Accepted: 03/10/2020] [Indexed: 02/07/2023]
Abstract
The search for novel compounds to combat multi-resistant bacterial infections includes exploring the potency of antimicrobial peptides and derivatives thereof. Complementary to high-throughput screening techniques, biophysical and biochemical studies of the biological activity of these compounds enable deep insight, which can be exploited in designing antimicrobial peptides with improved efficacy. This approach requires the combination of several techniques to study the effect of such peptides on both bacterial cells and simple mimics of their cell envelope, such as lipid-only vesicles. These efforts carry the challenge of bridging results across techniques and sample systems, including the proper choice of membrane mimics. This review describes some important concepts toward the development of potent antimicrobial peptides and how they translate to frequently applied experimental techniques, along with an outline of the biophysics pertaining to the killing mechanism of antimicrobial peptides.
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Affiliation(s)
- Nermina Malanovic
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, Graz, Austria.
| | - Lisa Marx
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, Graz, Austria
| | | | - Georg Pabst
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, Graz, Austria
| | - Enrico F Semeraro
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, Graz, Austria
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45
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Mahieu E, Ibrahim Z, Moulin M, Härtlein M, Franzetti B, Martel A, Gabel F. The power of SANS, combined with deuteration and contrast variation, for structural studies of functional and dynamic biomacromolecular systems in solution. EPJ WEB OF CONFERENCES 2020. [DOI: 10.1051/epjconf/202023603002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Small-angle neutron scattering (SANS), combined with macromolecular deuteration and solvent contrast variation (H2O/D2O exchange) allows focussing selectively on the signal of specific proteins in multi-protein complexes or mixtures of isolated proteins. We illustrate this unique capacity by the example of a functional protein-degradation system in solution, the PAN-20S proteasome complex in the presence of a protein substrate, ssrA-tagged GFP. By comparing experimental SANS data with synthetic SAXS (small-angle X-ray scattering) data, predicted for the same system under identical conditions, we show that SANS, when combined with macromolecular deuteration and solvent contrast variation, can specifically focus on the conformation of the PAN unfoldase, even in the presence of very large GFP aggregates. Likewise, structural information of native GFP states can be visualized in detail, even in the presence of the much larger PAN-20S unfoldase-protease oligomers, which would dominate the overall scattering signal when using X-rays instead of neutrons.
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46
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Lapinaite A, Carlomagno T, Gabel F. Small-Angle Neutron Scattering of RNA-Protein Complexes. Methods Mol Biol 2020; 2113:165-188. [PMID: 32006315 DOI: 10.1007/978-1-0716-0278-2_13] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Small-angle neutron scattering (SANS) provides structural information on biomacromolecules and their complexes in dilute solutions at the nanometer length scale. The overall dimensions, shapes, and interactions can be probed and compared to information obtained by complementary structural biology techniques such as crystallography, NMR, and EM. SANS, in combination with solvent H2O/D2O exchange and/or deuteration, is particularly well suited to probe the internal structure of RNA-protein (RNP) complexes since neutrons are more sensitive than X-rays to the difference in scattering length densities of proteins and RNA, with respect to an aqueous solvent. In this book chapter we provide a practical guide on how to carry out SANS experiments on RNP complexes, as well as possibilities of data analysis and interpretation.
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Affiliation(s)
- Audrone Lapinaite
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Teresa Carlomagno
- Centre for Biomolecular Drug Research, Leibniz University Hannover, Hannover, Germany.,Helmholtz Centre for Infection Research, Group of Structural Chemistry, Braunschweig, Germany
| | - Frank Gabel
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France.
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Hoogerheide DP, Forsyth VT, Brown KA. Neutron scattering for STRUCTURAL BIOLOGY: Modern neutron sources illuminate the complex functions of living systems. PHYSICS TODAY 2020; 73:10.1063/pt.3.4498. [PMID: 38487716 PMCID: PMC10938470 DOI: 10.1063/pt.3.4498] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
Modern neutron sources illuminate the complex functions of living systems.
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Affiliation(s)
- David P Hoogerheide
- National Institute of Standards and Technology Center for Neutron Research in Gaithersburg, Maryland
| | - V Trevor Forsyth
- Institut Laue-Langevin in Grenoble, France; he also holds a chair in biophysics at Keele University in the UK
| | - Katherine A Brown
- Cavendish Laboratory at Cambridge University in the UK and at the University of Texas at Austin
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48
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Small-Angle Scattering from Fractals: Differentiating between Various Types of Structures. Symmetry (Basel) 2020. [DOI: 10.3390/sym12010065] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Small-angle scattering (SAS; X-rays, neutrons, light) is being increasingly used to better understand the structure of fractal-based materials and to describe their interaction at nano- and micro-scales. To this aim, several minimalist yet specific theoretical models which exploit the fractal symmetry have been developed to extract additional information from SAS data. Although this problem can be solved exactly for many particular fractal structures, due to the intrinsic limitations of the SAS method, the inverse scattering problem, i.e., determination of the fractal structure from the intensity curve, is ill-posed. However, fractals can be divided into various classes, not necessarily disjointed, with the most common being random, deterministic, mass, surface, pore, fat and multifractals. Each class has its own imprint on the scattering intensity, and although one cannot uniquely identify the structure of a fractal based solely on SAS data, one can differentiate between various classes to which they belong. This has important practical applications in correlating their structural properties with physical ones. The article reviews SAS from several fractal models with an emphasis on describing which information can be extracted from each class, and how this can be performed experimentally. To illustrate this procedure and to validate the theoretical models, numerical simulations based on Monte Carlo methods are performed.
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50
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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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