1
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Durer ZA, İnce Hİ, Düvenci ZŞ, Timuçin E, Gräwert T, Orun O, Kan B, Sayers Z. Insights into the solution structure of the actin-binding tail domain of metavinculin by small angle X-ray scattering and molecular dynamics simulations. Int J Biol Macromol 2025:144376. [PMID: 40409637 DOI: 10.1016/j.ijbiomac.2025.144376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2025] [Revised: 05/07/2025] [Accepted: 05/17/2025] [Indexed: 05/25/2025]
Abstract
Vinculin is a ubiquitously expressed focal adhesion protein that plays an important role in cell-matrix and cell-to-cell junctions. Metavinculin, a muscle-specific splice variant of vinculin, contains a 68-amino acid disordered insert region in its actin binding tail domain (MVt). Mutations in this insert are linked to cardiomyopathies. This study investigates the solution structures and structural ensembles of wild-type (WT) and two mutant MVts, ΔLeu954 and R975W, which have been associated with cardiomyopathies, using small-angle X-ray scattering (SAXS) and molecular dynamics (MD) simulations. SAXS analyses revealed subtle differences in the estimated maximum dimensions and corroborated the elongated shape of the MVts. Quantitative comparisons of SAXS profiles indicated similarity between the WT and ΔLeu954, whereas R975W exhibited differences in the small-angle region. MD simulations demonstrated reduced conformational flexibility and greater packing of the insert in WT compared to mutants. Notably, a salt-bridge observed between R975 and D928 in a WT simulation provides a structural basis for the destabilization caused by the R975W mutation. These findings provide insights into the structure and dynamics of WT and mutant MVt, reflecting the promise of SAXS combined with MD simulations to elucidate the structural properties of proteins with structural disorder.
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Affiliation(s)
- Zeynep Aslıhan Durer
- School of Medicine, Department of Biophysics, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey; Faculty of Pharmacy, Department of Biochemistry, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey.
| | - Hande İpek İnce
- Institute of Health Sciences, Department of Biophysics, Marmara University, Istanbul, Turkey
| | - Zeynep Şevval Düvenci
- Institute of Health Sciences, Department of Biostatistics and Bioinformatics, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Emel Timuçin
- Institute of Health Sciences, Department of Biostatistics and Bioinformatics, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey; School of Medicine, Department of Biostatistics and Medical Informatics, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Tobias Gräwert
- European Molecular Biology Laboratory - Hamburg Unit, Biological Small Angle Scattering Group, Hamburg, Germany
| | - Oya Orun
- Institute of Health Sciences, Department of Biophysics, Marmara University, Istanbul, Turkey; School of Medicine, Department of Biophysics, Marmara University, Istanbul, Turkey
| | - Beki Kan
- School of Medicine, Department of Biophysics, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Zehra Sayers
- Faculty of Engineering and Natural Sciences, Molecular Biology, Genetics and Bioengineering Program, Sabanci University, İstanbul, Turkey
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2
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Fiorucci L, Schiavina M, Felli IC, Pierattelli R, Ravera E. Are Protein Conformational Ensembles in Agreement with Experimental Data? A Geometrical Interpretation of the Problem. J Chem Inf Model 2024; 64:5392-5401. [PMID: 38959217 DOI: 10.1021/acs.jcim.4c00582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
The conformational variability of biological macromolecules can play an important role in their biological function. Therefore, understanding conformational variability is expected to be key for predicting the behavior of a particular molecule in the context of organism-wide studies. Several experimental methods have been developed and deployed for accessing this information, and computational methods are continuously updated for the profitable integration of different experimental sources. The outcome of this endeavor is conformational ensembles, which may vary significantly in properties and composition when different ensemble reconstruction methods are used, and this raises the issue of comparing the predicted ensembles against experimental data. In this article, we discuss a geometrical formulation to provide a framework for understanding the agreement of an ensemble prediction to the experimental observations.
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Affiliation(s)
- Letizia Fiorucci
- Department of Chemistry "Ugo Schiff" and Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Marco Schiavina
- Department of Chemistry "Ugo Schiff" and Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Isabella C Felli
- Department of Chemistry "Ugo Schiff" and Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Roberta Pierattelli
- Department of Chemistry "Ugo Schiff" and Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Enrico Ravera
- Department of Chemistry "Ugo Schiff" and Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
- Florence Data Science, University of Florence, Viale G.B. Morgagni 59, 50134 Florence, Italy
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3
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Cohen T, Halfon M, Carter L, Sharkey B, Jain T, Sivasubramanian A, Schneidman-Duhovny D. Multi-state modeling of antibody-antigen complexes with SAXS profiles and deep-learning models. Methods Enzymol 2022; 678:237-262. [PMID: 36641210 DOI: 10.1016/bs.mie.2022.11.003] [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: 12/13/2022]
Abstract
Antibodies are an established class of human therapeutics. Epitope characterization is an important part of therapeutic antibody discovery. However, structural characterization of antibody-antigen complexes remains challenging. On the one hand, X-ray crystallography or cryo-electron microscopy provide atomic resolution characterization of the epitope, but the data collection process is typically long and the success rate is low. On the other hand, computational methods for modeling antibody-antigen structures from the individual components frequently suffer from a high false positive rate, rarely resulting in a unique solution. Recent deep learning models for structure prediction are also successful in predicting protein-protein complexes. However, they do not perform well for antibody-antigen complexes. Small Angle X-ray Scattering (SAXS) is a reliable technique for rapid structural characterization of protein samples in solution albeit at low resolution. Here, we present an integrative approach for modeling antigen-antibody complexes using the antibody sequence, antigen structure, and experimentally determined SAXS profiles of the antibody, antigen, and the complex. The method models antibody structures using a novel deep-learning approach, NanoNet. The structures of the antibodies and antigens are represented using multiple 3D conformations to account for compositional and conformational heterogeneity of the protein samples that are used to collect the SAXS data. The complexes are predicted by integrating the SAXS profiles with scoring functions for protein-protein interfaces that are based on statistical potentials and antibody-specific deep-learning models. We validated the method via application to four Fab:EGFR and one Fab:PCSK9 antibody:antigen complexes with experimentally available SAXS datasets. The integrative approach returns accurate predictions (interface RMSD<4Å) in the top five predictions for four out of five complexes (respective interface RMSD values of 1.95, 2.18, 2.66 and 3.87Å), providing support for the utility of such a computational pipeline for epitope characterization during therapeutic antibody discovery.
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Affiliation(s)
- Tomer Cohen
- The Rachel and Selim Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Matan Halfon
- The Rachel and Selim Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Lester Carter
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, United States
| | - Beth Sharkey
- High-Throughput Expression, Adimab LLC, Lebanon, NH, United States
| | - Tushar Jain
- Computational Biology, Adimab LLC, Palo Alto, CA, United States
| | | | - Dina Schneidman-Duhovny
- The Rachel and Selim Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel.
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4
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Linsenmeier L, Mohammadi B, Shafiq M, Frontzek K, Bär J, Shrivastava AN, Damme M, Song F, Schwarz A, Da Vela S, Massignan T, Jung S, Correia A, Schmitz M, Puig B, Hornemann S, Zerr I, Tatzelt J, Biasini E, Saftig P, Schweizer M, Svergun D, Amin L, Mazzola F, Varani L, Thapa S, Gilch S, Schätzl H, Harris DA, Triller A, Mikhaylova M, Aguzzi A, Altmeppen HC, Glatzel M. Ligands binding to the prion protein induce its proteolytic release with therapeutic potential in neurodegenerative proteinopathies. SCIENCE ADVANCES 2021; 7:eabj1826. [PMID: 34818048 PMCID: PMC8612689 DOI: 10.1126/sciadv.abj1826] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 09/20/2021] [Indexed: 05/07/2023]
Abstract
The prion protein (PrPC) is a central player in neurodegenerative diseases, such as prion diseases or Alzheimer’s disease. In contrast to disease-promoting cell surface PrPC, extracellular fragments act neuroprotective by blocking neurotoxic disease-associated protein conformers. Fittingly, PrPC release by the metalloprotease ADAM10 represents a protective mechanism. We used biochemical, cell biological, morphological, and structural methods to investigate mechanisms stimulating this proteolytic shedding. Shed PrP negatively correlates with prion conversion and is markedly redistributed in murine brain in the presence of prion deposits or amyloid plaques, indicating a sequestrating activity. PrP-directed ligands cause structural changes in PrPC and increased shedding in cells and organotypic brain slice cultures. As an exception, some PrP-directed antibodies targeting repetitive epitopes do not cause shedding but surface clustering, endocytosis, and degradation of PrPC. Both mechanisms may contribute to beneficial actions described for PrP-directed ligands and pave the way for new therapeutic strategies against currently incurable neurodegenerative diseases.
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Affiliation(s)
- Luise Linsenmeier
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Behnam Mohammadi
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Mohsin Shafiq
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Karl Frontzek
- Institute of Neuropathology, University of Zurich, Zürich, Switzerland
| | - Julia Bär
- Institute of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
- Center for Molecular Neurobiology Hamburg (ZMNH), UKE, Hamburg, Germany
| | - Amulya N. Shrivastava
- École Normale Supérieure, Institut de Biologie de l’ENS (IBENS), INSERM, CNRS, PSL Research University, Paris, France
| | - Markus Damme
- Institute of Biochemistry, Christian Albrechts University, Kiel, Germany
| | - Feizhi Song
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Alexander Schwarz
- Institute of Nanostructure and Solid State Physics, Universität Hamburg, Hamburg, Germany
| | - Stefano Da Vela
- European Molecular Biology Laboratory (EMBL), Hamburg, Germany
| | - Tania Massignan
- Dulbecco Telethon Laboratory of Prions and Amyloids, CIBIO, University of Trento, Trento, Italy
| | - Sebastian Jung
- Department Biochemistry of Neurodegenerative Diseases, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Angela Correia
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Matthias Schmitz
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Berta Puig
- Department of Neurology, Experimental Research in Stroke and Inflammation, UKE, Hamburg, Germany
| | - Simone Hornemann
- Institute of Neuropathology, University of Zurich, Zürich, Switzerland
| | - Inga Zerr
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Jörg Tatzelt
- Department Biochemistry of Neurodegenerative Diseases, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
- Cluster of Excellence RESOLV, Bochum, Germany
| | - Emiliano Biasini
- Dulbecco Telethon Laboratory of Prions and Amyloids, CIBIO, University of Trento, Trento, Italy
| | - Paul Saftig
- Institute of Biochemistry, Christian Albrechts University, Kiel, Germany
| | | | - Dmitri Svergun
- European Molecular Biology Laboratory (EMBL), Hamburg, Germany
| | - Ladan Amin
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Federica Mazzola
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona, Switzerland
| | - Luca Varani
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona, Switzerland
| | - Simrika Thapa
- Calgary Prion Research Unit, University of Calgary, Calgary, Alberta, Canada
| | - Sabine Gilch
- Calgary Prion Research Unit, University of Calgary, Calgary, Alberta, Canada
| | - Hermann Schätzl
- Calgary Prion Research Unit, University of Calgary, Calgary, Alberta, Canada
| | - David A. Harris
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Antoine Triller
- École Normale Supérieure, Institut de Biologie de l’ENS (IBENS), INSERM, CNRS, PSL Research University, Paris, France
| | - Marina Mikhaylova
- Institute of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
- Center for Molecular Neurobiology Hamburg (ZMNH), UKE, Hamburg, Germany
| | - Adriano Aguzzi
- Institute of Neuropathology, University of Zurich, Zürich, Switzerland
| | - Hermann C. Altmeppen
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
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5
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Chen EHL, Lin KM, Sang JC, Ho MR, Lee CH, Shih O, Su CJ, Yeh YQ, Jeng US, Chen RPY. Condition-dependent structural collapse in the intrinsically disordered N-terminal domain of prion protein. IUBMB Life 2021; 74:780-793. [PMID: 34288372 DOI: 10.1002/iub.2528] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/25/2021] [Accepted: 06/27/2021] [Indexed: 11/06/2022]
Abstract
Prion protein is composed of a structure-unsolved N-terminal domain and a globular C-terminal domain. Under limited trypsin digestion, mouse recombinant prion protein can be cleaved into two parts at residue Lys105. Here, we termed these two fragments as the N-domain (sequence 23-105) and the C-domain (sequence 106-230). In this study, the structural properties of the N-domain, the C-domain, and the full-length protein were explored using small-angle X-ray scattering, analytical ultracentrifugation, circular dichroism spectroscopy, and the 8-anilino-1-naphthalenesulfonic acid binding assay. The conformation and size of the prion protein were found to change sensitively under the solvent conditions. The positive residues in the sequence 23-99 of the N-domain were found to be responsible for the enhanced flexibility with the salt concentration reduced below 5 mM. The C-domain containing a hydrophobic patch tends to unfold and aggregate during a salt-induced structural collapse. The N-domain collapsed together with the C-domain at pH 5.2, whereas it collapsed independently at pH 4.2. The positively charged cluster (sequence 100-105) in the N-domain contributed to protecting the exposed hydrophobic surface of the C-domain.
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Affiliation(s)
- Eric H-L Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Kuei-Ming Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Jason C Sang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Meng-Ru Ho
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chih-Hsuan Lee
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Orion Shih
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Chun-Jen Su
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Yi-Qi Yeh
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - U-Ser Jeng
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan.,Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | - Rita P-Y Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan.,Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, Taiwan
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6
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Ding C, Wang S, Zhang Z. Integrating an Enhanced Sampling Method and Small-Angle X-Ray Scattering to Study Intrinsically Disordered Proteins. Front Mol Biosci 2021; 8:621128. [PMID: 34150843 PMCID: PMC8213455 DOI: 10.3389/fmolb.2021.621128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 02/08/2021] [Indexed: 11/23/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) have been paid more and more attention over the past decades because they are involved in a multitude of crucial biological functions. Despite their functional importance, IDPs are generally difficult to investigate because they are very flexible and lack stable structures. Computer simulation may serve as a useful tool in studying IDPs. With the development of computer software and hardware, computational methods, such as molecular dynamics (MD) simulations, are popularly used. However, there is a sampling problem in MD simulations. In this work, this issue is investigated using an IDP called unique long region 11 (UL11), which is the conserved outer tegument component from herpes simplex virus 1. After choosing a proper force field and water model that is suitable for simulating IDPs, integrative modeling by combining an enhanced sampling method and experimental data like small-angle X-ray scattering (SAXS) is utilized to efficiently sample the conformations of UL11. The simulation results are in good agreement with experimental data. This work may provide a general protocol to study structural ensembles of IDPs.
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Affiliation(s)
- Chengtao Ding
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, National Science Center for Physical Sciences at Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | | | - Zhiyong Zhang
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, National Science Center for Physical Sciences at Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
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7
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Sali A. From integrative structural biology to cell biology. J Biol Chem 2021; 296:100743. [PMID: 33957123 PMCID: PMC8203844 DOI: 10.1016/j.jbc.2021.100743] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/09/2021] [Accepted: 04/30/2021] [Indexed: 12/16/2022] Open
Abstract
Integrative modeling is an increasingly important tool in structural biology, providing structures by combining data from varied experimental methods and prior information. As a result, molecular architectures of large, heterogeneous, and dynamic systems, such as the ∼52-MDa Nuclear Pore Complex, can be mapped with useful accuracy, precision, and completeness. Key challenges in improving integrative modeling include expanding model representations, increasing the variety of input data and prior information, quantifying a match between input information and a model in a Bayesian fashion, inventing more efficient structural sampling, as well as developing better model validation, analysis, and visualization. In addition, two community-level challenges in integrative modeling are being addressed under the auspices of the Worldwide Protein Data Bank (wwPDB). First, the impact of integrative structures is maximized by PDB-Development, a prototype wwPDB repository for archiving, validating, visualizing, and disseminating integrative structures. Second, the scope of structural biology is expanded by linking the wwPDB resource for integrative structures with archives of data that have not been generally used for structure determination but are increasingly important for computing integrative structures, such as data from various types of mass spectrometry, spectroscopy, optical microscopy, proteomics, and genetics. To address the largest of modeling problems, a type of integrative modeling called metamodeling is being developed; metamodeling combines different types of input models as opposed to different types of data to compute an output model. Collectively, these developments will facilitate the structural biology mindset in cell biology and underpin spatiotemporal mapping of the entire cell.
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Affiliation(s)
- Andrej Sali
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, the Department of Bioengineering and Therapeutic Sciences, the Quantitative Biosciences Institute (QBI), and the Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA.
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Antibody Fragments as Tools for Elucidating Structure-Toxicity Relationships and for Diagnostic/Therapeutic Targeting of Neurotoxic Amyloid Oligomers. Int J Mol Sci 2020; 21:ijms21238920. [PMID: 33255488 PMCID: PMC7727795 DOI: 10.3390/ijms21238920] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/01/2020] [Accepted: 10/01/2020] [Indexed: 02/06/2023] Open
Abstract
The accumulation of amyloid protein aggregates in tissues is the basis for the onset of diseases known as amyloidoses. Intriguingly, many amyloidoses impact the central nervous system (CNS) and usually are devastating diseases. It is increasingly apparent that neurotoxic soluble oligomers formed by amyloidogenic proteins are the primary molecular drivers of these diseases, making them lucrative diagnostic and therapeutic targets. One promising diagnostic/therapeutic strategy has been the development of antibody fragments against amyloid oligomers. Antibody fragments, such as fragment antigen-binding (Fab), scFv (single chain variable fragments), and VHH (heavy chain variable domain or single-domain antibodies) are an alternative to full-length IgGs as diagnostics and therapeutics for a variety of diseases, mainly because of their increased tissue penetration (lower MW compared to IgG), decreased inflammatory potential (lack of Fc domain), and facile production (low structural complexity). Furthermore, through the use of in vitro-based ligand selection, it has been possible to identify antibody fragments presenting marked conformational selectivity. In this review, we summarize significant reports on antibody fragments selective for oligomers associated with prevalent CNS amyloidoses. We discuss promising results obtained using antibody fragments as both diagnostic and therapeutic agents against these diseases. In addition, the use of antibody fragments, particularly scFv and VHH, in the isolation of unique oligomeric assemblies is discussed as a strategy to unravel conformational moieties responsible for neurotoxicity. We envision that advances in this field may lead to the development of novel oligomer-selective antibody fragments with superior selectivity and, hopefully, good clinical outcomes.
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Lansky S, Salama R, Shulami S, Lavid N, Sen S, Schapiro I, Shoham Y, Shoham G. Carbohydrate-Binding Capability and Functional Conformational Changes of AbnE, an Arabino-oligosaccharide Binding Protein. J Mol Biol 2020; 432:2099-2120. [PMID: 32067952 DOI: 10.1016/j.jmb.2020.01.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 01/19/2020] [Accepted: 01/30/2020] [Indexed: 11/27/2022]
Abstract
ABC importers are membrane proteins responsible for the transport of nutrients into the cells of prokaryotes. Although the structures of ABC importers vary, all contain four conserved domains: two nucleotide-binding domains (NBDs), which bind and hydrolyze ATP, and two transmembrane domains (TMDs), which help translocate the substrate. ABC importers are also dependent on an additional protein component, a high-affinity substrate-binding protein (SBP) that specifically binds the target ligand for delivery to the appropriate ABC transporter. AbnE is a SBP belonging to the ABC importer for arabino-oligosaccharides in the Gram-positive thermophilic bacterium Geobacillus stearothermophilus. Using isothermal titration calorimetry (ITC), purified AbnE was shown to bind medium-sized arabino-oligosaccharides, in the range of arabino-triose (A3) to arabino-octaose (A8), all with Kd values in the nanomolar range. We describe herein the 3D structure of AbnE in its closed conformation in complex with a wide range of arabino-oligosaccharide substrates (A2-A8). These structures provide the basis for the detailed structural analysis of the AbnE-sugar complexes, and together with complementary quantum chemical calculations, site-specific mutagenesis, and isothermal titration calorimetry (ITC) experiments, provide detailed insights into the AbnE-substrate interactions involved. Small-angle X-ray scattering (SAXS) experiments and normal mode analysis (NMA) are used to study the conformational changes of AbnE, and these data, taken together, suggest clues regarding its binding mode to the full ABC importer.
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Affiliation(s)
- Shifra Lansky
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Rachel Salama
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, 32000, Israel
| | - Smadar Shulami
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, 32000, Israel
| | - Noa Lavid
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, 32000, Israel
| | - Saumik Sen
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel; Fritz Haber Center for Molecular Dynamics Research, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Igor Schapiro
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel; Fritz Haber Center for Molecular Dynamics Research, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Yuval Shoham
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, 32000, Israel.
| | - Gil Shoham
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
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10
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Rout MP, Sali A. Principles for Integrative Structural Biology Studies. Cell 2020; 177:1384-1403. [PMID: 31150619 DOI: 10.1016/j.cell.2019.05.016] [Citation(s) in RCA: 185] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/24/2019] [Accepted: 05/06/2019] [Indexed: 12/22/2022]
Abstract
Integrative structure determination is a powerful approach to modeling the structures of biological systems based on data produced by multiple experimental and theoretical methods, with implications for our understanding of cellular biology and drug discovery. This Primer introduces the theory and methods of integrative approaches, emphasizing the kinds of data that can be effectively included in developing models and using the nuclear pore complex as an example to illustrate the practice and challenges involved. These guidelines are intended to aid the researcher in understanding and applying integrative structural methods to systems of their interest and thus take advantage of this rapidly evolving field.
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Affiliation(s)
- Michael P Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065, USA.
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, Byers Hall, 1700 4th Street, Suite 503B, University of California, San Francisco, San Francisco, CA 94158, USA.
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11
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Salzano G, Brennich M, Mancini G, Tran TH, Legname G, D'Angelo P, Giachin G. Deciphering Copper Coordination in the Mammalian Prion Protein Amyloidogenic Domain. Biophys J 2020; 118:676-687. [PMID: 31952810 DOI: 10.1016/j.bpj.2019.12.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 12/19/2019] [Accepted: 12/23/2019] [Indexed: 12/17/2022] Open
Abstract
Prions are pathological isoforms of the cellular prion protein that is responsible for transmissible spongiform encephalopathies (TSE). Cellular prion protein interacts with copper, Cu(II), through octarepeat and nonoctarepeat (non-OR) binding sites. The molecular details of Cu(II) coordination within the non-OR region are not well characterized yet. By the means of small angle x-ray scattering and x-ray absorption spectroscopic methods, we have investigated the effect of Cu(II) on prion protein folding and its coordination geometries when bound to the non-OR region of recombinant prion proteins (recPrP) from mammalian species considered resistant or susceptible to TSE. As the prion resistant model, we used ovine recPrP (OvPrP) carrying the protective polymorphism at residues A136, R154, and R171, whereas as TSE-susceptible models, we employed OvPrP with V136, R154, and Q171 polymorphism and bank vole recPrP. Our analysis reveals that Cu(II) affects the structural plasticity of the non-OR region, leading to a more compacted conformation. We then identified two Cu(II) coordination geometries: in the type 1 coordination observed in OvPrP at residues A136, R154, and R171, the metal is coordinated by four residues; conversely, the type 2 coordination is present in OvPrP with V136, R154, and Q171 and bank vole recPrP, where Cu(II) is coordinated by three residues and by one water molecule, making the non-OR region more exposed to the solvent. These changes in copper coordination affect the recPrP amyloid aggregation. This study may provide new insights into the molecular mechanisms governing the resistance or susceptibility of certain species to TSE.
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Affiliation(s)
- Giulia Salzano
- Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Martha Brennich
- European Molecular Biology Laboratory (EMBL), Grenoble Outstation, Grenoble, France
| | - Giordano Mancini
- Scuola Normale Superiore, Pisa, Italy; Istituto Nazionale di Fisica Nucleare (INFN), Pisa, Italy
| | - Thanh Hoa Tran
- Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Giuseppe Legname
- Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy; ELETTRA-Sincrotrone Trieste S.C.p.A, Trieste, Italy
| | - Paola D'Angelo
- Department of Chemistry, Sapienza University of Rome, Rome, Italy.
| | - Gabriele Giachin
- European Synchrotron Radiation Facility (ESRF), Grenoble, France.
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12
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Structural Organization and Dynamics of Homodimeric Cytohesin Family Arf GTPase Exchange Factors in Solution and on Membranes. Structure 2019; 27:1782-1797.e7. [PMID: 31601460 PMCID: PMC6948192 DOI: 10.1016/j.str.2019.09.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/03/2019] [Accepted: 09/16/2019] [Indexed: 12/30/2022]
Abstract
Membrane dynamic processes require Arf GTPase activation by guanine nucleotide exchange factors (GEFs) with a Sec7 domain. Cytohesin family Arf GEFs function in signaling and cell migration through Arf GTPase activation on the plasma membrane and endosomes. In this study, the structural organization of two cytohesins (Grp1 and ARNO) was investigated in solution by size exclusion-small angle X-ray scattering and negative stain-electron microscopy and on membranes by dynamic light scattering, hydrogen-deuterium exchange-mass spectrometry and guanosine diphosphate (GDP)/guanosine triphosphate (GTP) exchange assays. The results suggest that cytohesins form elongated dimers with a central coiled coil and membrane-binding pleckstrin-homology (PH) domains at opposite ends. The dimers display significant conformational heterogeneity, with a preference for compact to intermediate conformations. Phosphoinositide-dependent membrane recruitment is mediated by one PH domain at a time and alters the conformational dynamics to prime allosteric activation by Arf-GTP. A structural model for membrane targeting and allosteric activation of full-length cytohesin dimers is discussed.
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13
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Wu H, Saltzberg DJ, Kratochvil HT, Jo H, Sali A, DeGrado WF. Glutamine Side Chain 13C═ 18O as a Nonperturbative IR Probe of Amyloid Fibril Hydration and Assembly. J Am Chem Soc 2019; 141:7320-7326. [PMID: 30998340 DOI: 10.1021/jacs.9b00577] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Infrared (IR) spectroscopy has provided considerable insight into the structures, dynamics, and formation mechanisms of amyloid fibrils. IR probes, such as main chain 13C═18O, have been widely employed to obtain site-specific structural information, yet only secondary structures and strand-to-strand arrangements can be probed. Very few nonperturbative IR probes are available to report on the side-chain conformation and environments, which are critical to determining sheet-to-sheet arrangements in steric zippers within amyloids. Polar residues, such as glutamine, contribute significantly to the stability of amyloids and thus are frequently found in core regions of amyloid peptides/proteins. Furthermore, polyglutamine (polyQ) repeats form toxic aggregates in several neurodegenerative diseases. Here we report the synthesis and application of a new nonperturbative IR probe-glutamine side chain 13C═18O. We use side chain 13C═18O labeling and isotope dilution to detect the presence of intermolecularly hydrogen-bonded arrays of glutamine side chains (Gln ladders) in amyloid-forming peptides. Moreover, the line width of the 13C═18O peak is highly sensitive to its local hydration environment. The IR data from side chain labeling allows us to unambiguously determine the sheet-to-sheet arrangement in a short amyloid-forming peptide, GNNQQNY, providing insight that was otherwise inaccessible through main chain labeling. With several different fibril samples, we also show the versatility of this IR probe in studying the structures and aggregation kinetics of amyloids. Finally, we demonstrate the capability of modeling amyloid structures with IR data using the integrative modeling platform (IMP) and the potential of integrating IR with other biophysical methods for more accurate structural modeling. Together, we believe that side chain 13C═18O will complement main chain isotope labeling in future IR studies of amyloids and integrative modeling using IR data will significantly expand the power of IR spectroscopy to elucidate amyloid assemblies.
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14
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Braitbard M, Schneidman-Duhovny D, Kalisman N. Integrative Structure Modeling: Overview and Assessment. Annu Rev Biochem 2019; 88:113-135. [PMID: 30830798 DOI: 10.1146/annurev-biochem-013118-111429] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Integrative structure modeling computationally combines data from multiple sources of information with the aim of obtaining structural insights that are not revealed by any single approach alone. In the first part of this review, we survey the commonly used sources of structural information and the computational aspects of model building. Throughout the past decade, integrative modeling was applied to various biological systems, with a focus on large protein complexes. Recent progress in the field of cryo-electron microscopy (cryo-EM) has resolved many of these complexes to near-atomic resolution. In the second part of this review, we compare a range of published integrative models with their higher-resolution counterparts with the aim of critically assessing their accuracy. This comparison gives a favorable view of integrative modeling and demonstrates its ability to yield accurate and informative results. We discuss possible roles of integrative modeling in the new era of cryo-EM and highlight future challenges and directions.
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Affiliation(s)
- Merav Braitbard
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel;
| | - Dina Schneidman-Duhovny
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; .,School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel;
| | - Nir Kalisman
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel;
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15
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Saltzberg D, Greenberg CH, Viswanath S, Chemmama I, Webb B, Pellarin R, Echeverria I, Sali A. Modeling Biological Complexes Using Integrative Modeling Platform. Methods Mol Biol 2019; 2022:353-377. [PMID: 31396911 DOI: 10.1007/978-1-4939-9608-7_15] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Integrative structure modeling provides 3D models of macromolecular systems that are based on information from multiple types of experiments, physical principles, statistical inferences, and prior structural models. Here, we provide a hands-on realistic example of integrative structure modeling of the quaternary structure of the actin, tropomyosin, and gelsolin protein assembly based on electron microscopy, solution X-ray scattering, and chemical crosslinking data for the complex as well as excluded volume, sequence connectivity, and rigid atomic X-ray structures of the individual subunits. We follow the general four-stage process for integrative modeling, including gathering the input information, converting the input information into a representation of the system and a scoring function, sampling alternative model configurations guided by the scoring function, and analyzing the results. The computational aspects of this approach are implemented in our open-source Integrative Modeling Platform (IMP), a comprehensive and extensible software package for integrative modeling ( https://integrativemodeling.org ). In particular, we rely on the Python Modeling Interface (PMI) module of IMP that provides facile mixing and matching of macromolecular representations, restraints based on different types of information, sampling algorithms, and analysis including validations of the input data and output models. Finally, we also outline how to deposit an integrative structure and corresponding experimental data into PDB-Dev, the nascent worldwide Protein Data Bank (wwPDB) resource for archiving and disseminating integrative structures ( https://pdb-dev.wwpdb.org ). The example application provides a starting point for a user interested in using IMP for integrative modeling of other biomolecular systems.
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Affiliation(s)
- Daniel Saltzberg
- California Institute for Quantitative Biosciences, University of California, San Francisco, CA, USA
| | - Charles H Greenberg
- California Institute for Quantitative Biosciences, University of California, San Francisco, CA, USA
| | - Shruthi Viswanath
- California Institute for Quantitative Biosciences, University of California, San Francisco, CA, USA
| | - Ilan Chemmama
- California Institute for Quantitative Biosciences, University of California, San Francisco, CA, USA
| | - Ben Webb
- California Institute for Quantitative Biosciences, University of California, San Francisco, CA, USA
| | - Riccardo Pellarin
- Structural Bioinformatics Unit, Institut Pasteur, CNRS UMR 3528, Paris, France
| | - Ignacia Echeverria
- California Institute for Quantitative Biosciences, University of California, San Francisco, CA, USA
| | - Andrej Sali
- California Institute for Quantitative Biosciences, University of California, San Francisco, CA, USA.
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16
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Piiadov V, Ares de Araújo E, Oliveira Neto M, Craievich AF, Polikarpov I. SAXSMoW 2.0: Online calculator of the molecular weight of proteins in dilute solution from experimental SAXS data measured on a relative scale. Protein Sci 2018; 28:454-463. [PMID: 30371978 DOI: 10.1002/pro.3528] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/05/2018] [Accepted: 10/08/2018] [Indexed: 11/07/2022]
Abstract
Knowledge of molecular weight, oligomeric states, and quaternary arrangements of proteins in solution is fundamental for understanding their molecular functions and activities. We describe here a program SAXSMoW 2.0 for robust and quick determination of molecular weight and oligomeric state of proteins in dilute solution, starting from a single experimental small-angle scattering intensity curve, I(q), measured on a relative scale. The first version of this calculator has been widely used during the last decade and applied to analyze experimental SAXS data of many proteins and protein complexes. SAXSMoW 2.0 exhibits new features which allow for the direct input of experimental intensity curves and also automatic modes for quick determinations of the radius of gyration, volume, and molecular weight. The new program was extensively tested by applying it to many experimental SAXS curves downloaded from the open databases, corresponding to proteins with different shapes and molecular weights ranging from ~10 kDa up to about ~500 kDa and different shapes from globular to elongated. These tests reveal that the use of SAXSMoW 2.0 allows for determinations of molecular weights of proteins in dilute solution with a median discrepancy of about 12% for globular proteins. In case of elongated molecules, discrepancy value can be significantly higher. Our tests show discrepancies of approximately 21% for the proteins with molecular shape aspect ratios up to 18.
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Affiliation(s)
- Vassili Piiadov
- Institute of Physics of São Carlos, University of São Paulo, São Carlos, São Paulo, Brazil
| | - Evandro Ares de Araújo
- Institute of Physics of São Carlos, University of São Paulo, São Carlos, São Paulo, Brazil
| | - Mario Oliveira Neto
- Institute of Biosciences, University Estadual Paulista, Botucatu, São Paulo, Brazil
| | | | - Igor Polikarpov
- Institute of Physics of São Carlos, University of São Paulo, São Carlos, São Paulo, Brazil
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17
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Hardouin P, Velours C, Bou-Nader C, Assrir N, Laalami S, Putzer H, Durand D, Golinelli-Pimpaneau B. Dissociation of the Dimer of the Intrinsically Disordered Domain of RNase Y upon Antibody Binding. Biophys J 2018; 115:2102-2113. [PMID: 30447990 DOI: 10.1016/j.bpj.2018.10.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 09/17/2018] [Accepted: 10/17/2018] [Indexed: 12/12/2022] Open
Abstract
Although RNase Y acts as the key enzyme initiating messenger RNA decay in Bacillus subtilis and likely in many other Gram-positive bacteria, its three-dimensional structure remains unknown. An antibody belonging to the rare immunoglobulin G (IgG) 2b λx isotype was raised against a 12-residue conserved peptide from the N-terminal noncatalytic domain of B. subtilis RNase Y (BsRNaseY) that is predicted to be intrinsically disordered. Here, we show that this domain can be produced as a stand-alone protein called Nter-BsRNaseY that undergoes conformational changes between monomeric and dimeric forms. Circular dichroism and size exclusion chromatography coupled with multiangle light scattering or with small angle x-ray scattering indicate that the Nter-BsRNaseY dimer displays an elongated form and a high content of α-helices, in agreement with the existence of a central coiled-coil structure appended with flexible ends, and that the monomeric state of Nter-BsRNaseY is favored upon binding the fragment antigen binding (Fab) of the antibody. The dissociation constants of the IgG/BsRNaseY, IgG/Nter-BsRNaseY, and IgG/peptide complexes indicate that the affinity of the IgG for Nter-BsRNaseY is in the nM range and suggest that the peptide is less accessible in BsRNaseY than in Nter-BsRNaseY. The crystal structure of the Fab in complex with the peptide antigen shows that the peptide adopts an elongated U-shaped conformation in which the unique hydrophobic residue of the peptide, Leu6, is completely buried. The peptide/Fab complex may mimic the interaction of a microdomain of the N-terminal domain of BsRNaseY with one of its cellular partners within the degradosome complex. Altogether, our results suggest that BsRNaseY may become accessible for protein interaction upon dissociation of its N-terminal domain into the monomeric form.
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Affiliation(s)
- Pierre Hardouin
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Université Pierre et Marie Curie, Paris CEDEX 05, France
| | - Christophe Velours
- Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette CEDEX, France
| | - Charles Bou-Nader
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Université Pierre et Marie Curie, Paris CEDEX 05, France
| | - Nadine Assrir
- Structural Chemistry and Biology Team, Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Soumaya Laalami
- CNRS UMR8261-Université Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, Paris, France
| | - Harald Putzer
- CNRS UMR8261-Université Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, Paris, France
| | - Dominique Durand
- Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette CEDEX, France
| | - Béatrice Golinelli-Pimpaneau
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Université Pierre et Marie Curie, Paris CEDEX 05, France.
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18
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Bhattacharya S, Xu L, Thompson D. Revisiting the earliest signatures of amyloidogenesis: Roadmaps emerging from computational modeling and experiment. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2018. [DOI: 10.1002/wcms.1359] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Shayon Bhattacharya
- Department of Physics, Bernal InstituteUniversity of LimerickLimerickIreland
| | - Liang Xu
- Department of Physics, Bernal InstituteUniversity of LimerickLimerickIreland
| | - Damien Thompson
- Department of Physics, Bernal InstituteUniversity of LimerickLimerickIreland
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19
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Abstract
Small-angle X-ray scattering (SAXS) is an increasingly common and useful technique for structural characterization of molecules in solution. A SAXS experiment determines the scattering intensity of a molecule as a function of spatial frequency, termed SAXS profile. SAXS profiles can be utilized in a variety of molecular modeling applications, such as comparing solution and crystal structures, structural characterization of flexible proteins, assembly of multi-protein complexes, and modeling of missing regions in the high-resolution structure. Here, we describe protocols for modeling atomic structures based on SAXS profiles. The first protocol is for comparing solution and crystal structures including modeling of missing regions and determination of the oligomeric state. The second protocol performs multi-state modeling by finding a set of conformations and their weights that fit the SAXS profile starting from a single-input structure. The third protocol is for protein-protein docking based on the SAXS profile of the complex. We describe the underlying software, followed by demonstrating their application on interleukin 33 (IL33) with its primary receptor ST2 and DNA ligase IV-XRCC4 complex.
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Affiliation(s)
- Dina Schneidman-Duhovny
- School of Computer Science and Engineering, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Michal Hammel
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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20
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Kadowaki MAS, Higasi P, de Godoy MO, Prade RA, Polikarpov I. Biochemical and structural insights into a thermostable cellobiohydrolase from Myceliophthora thermophila. FEBS J 2018; 285:559-579. [PMID: 29222836 DOI: 10.1111/febs.14356] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/20/2017] [Accepted: 12/05/2017] [Indexed: 12/27/2022]
Abstract
Cellobiohydrolases hydrolyze cellulose, a linear polymer with glucose monomers linked exclusively by β-1,4 glycosidic linkages. The widespread hydrogen bonding network tethers individual cellulose polymers forming crystalline cellulose, which prevent the access of hydrolytic enzymes and water molecules. The most abundant enzyme secreted by Myceliophthora thermophila M77 in response to the presence of biomass is the cellobiohydrolase MtCel7A, which is composed by a GH7-catalytic domain (CD), a linker, and a CBM1-type carbohydrate-binding module. GH7 cellobiohydrolases have been studied before, and structural models have been proposed. However, currently available GH7 crystal structures only define separate catalytic domains and/or cellulose-binding modules and do not include the full-length structures that are involved in shaping the catalytic mode of operation. In this study, we determined the 3D structure of catalytic domain using X-ray crystallography and retrieved the full-length enzyme envelope via small-angle X-ray scattering (SAXS) technique. The SAXS data reveal a tadpole-like molecular shape with a rigid linker connecting the CD and CBM. Our biochemical studies show that MtCel7A has higher catalytic efficiency and thermostability as well as lower processivity when compared to the well-studied TrCel7A from Trichoderma reesei. Based on a comparison of the crystallographic structures of CDs and their molecular dynamic simulations, we demonstrate that MtCel7A has considerably higher flexibility than TrCel7A. In particular, loops that cover the active site are more flexible and undergo higher conformational fluctuations, which might account for decreased processivity and enhanced enzymatic efficiency. Our statistical coupling analysis suggests co-evolution of amino acid clusters comprising the catalytic site of MtCel7A, which correlate with the steps in the catalytic cycle of the enzyme. DATABASE The atomic coordinates and structural factors of MtCel7A have been deposited in the Protein Data Bank with accession number 5W11.
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Affiliation(s)
| | - Paula Higasi
- São Carlos Institute of Physics, University of São Paulo, Brazil
| | | | - Rolf A Prade
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Igor Polikarpov
- São Carlos Institute of Physics, University of São Paulo, Brazil
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21
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Malaby AW, Das S, Chakravarthy S, Irving TC, Bilsel O, Lambright DG. Structural Dynamics Control Allosteric Activation of Cytohesin Family Arf GTPase Exchange Factors. Structure 2017; 26:106-117.e6. [PMID: 29276036 PMCID: PMC5752578 DOI: 10.1016/j.str.2017.11.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 10/22/2017] [Accepted: 11/27/2017] [Indexed: 11/16/2022]
Abstract
Membrane dynamic processes including vesicle biogenesis depend on Arf
GTPase activation by guanine nucleotide exchange factors (GEFs) containing a
catalytic Sec7 domain and a membrane targeting module such as a PH domain. The
catalytic output of cytohesin family Arf GEFs is controlled by autoinhibitory
interactions that impede accessibility of the exchange site in the Sec7 domain.
These restraints can be relieved through activator Arf-GTP binding to an
allosteric site comprising the PH domain and proximal autoinhibitory elements
(Sec7-PH linker and C-terminal helix). Small angle X-ray scattering and
negative-stain electron microscopy were used to investigate the structural
organization and conformational dynamics of Cytohesin-3 (Grp1) in autoinhibited
and active states. The results support a model in which hinge dynamics in the
autoinhibited state expose the activator site for Arf-GTP binding, while
subsequent C-terminal helix unlatching and repositioning unleash conformational
entropy in the Sec7-PH linker to drive exposure of the exchange site.
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Affiliation(s)
- Andrew W Malaby
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Sanchaita Das
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Srinivas Chakravarthy
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Thomas C Irving
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Osman Bilsel
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - David G Lambright
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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22
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Trewhella J, Duff AP, Durand D, Gabel F, Guss JM, Hendrickson WA, Hura GL, Jacques DA, Kirby NM, Kwan AH, Pérez J, Pollack L, Ryan TM, Sali A, Schneidman-Duhovny D, Schwede T, Svergun DI, Sugiyama M, Tainer JA, Vachette P, Westbrook J, Whitten AE. 2017 publication guidelines for structural modelling of small-angle scattering data from biomolecules in solution: an update. Acta Crystallogr D Struct Biol 2017; 73:710-728. [PMID: 28876235 PMCID: PMC5586245 DOI: 10.1107/s2059798317011597] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 08/07/2017] [Indexed: 12/02/2022] Open
Abstract
In 2012, preliminary guidelines were published addressing sample quality, data acquisition and reduction, presentation of scattering data and validation, and modelling for biomolecular small-angle scattering (SAS) experiments. Biomolecular SAS has since continued to grow and authors have increasingly adopted the preliminary guidelines. In parallel, integrative/hybrid determination of biomolecular structures is a rapidly growing field that is expanding the scope of structural biology. For SAS to contribute maximally to this field, it is essential to ensure open access to the information required for evaluation of the quality of SAS samples and data, as well as the validity of SAS-based structural models. To this end, the preliminary guidelines for data presentation in a publication are reviewed and updated, and the deposition of data and associated models in a public archive is recommended. These guidelines and recommendations have been prepared in consultation with the members of the International Union of Crystallography (IUCr) Small-Angle Scattering and Journals Commissions, the Worldwide Protein Data Bank (wwPDB) Small-Angle Scattering Validation Task Force and additional experts in the field.
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Affiliation(s)
- Jill Trewhella
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia
| | - Anthony P. Duff
- ANSTO, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Dominique Durand
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Bâtiment 430, Université Paris-Sud, 91405 Orsay CEDEX, France
| | - Frank Gabel
- Université Grenoble Alpes, Commissariat à l’Energie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale (IBS), and Institut Laue–Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - J. Mitchell Guss
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia
| | - Wayne A. Hendrickson
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Greg L. Hura
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - David A. Jacques
- University of Technology Sydney, ithree Institute, 15 Broadway, Ultimo, NSW 2007, Australia
| | - Nigel M. Kirby
- Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168, Australia
| | - Ann H. Kwan
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia
| | - Javier Pérez
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin BP48, 91192 Gif-sur-Yvette CEDEX, France
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853-2501, USA
| | - Timothy M. Ryan
- Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168, Australia
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, and California Institute for Quantitative Biosciences (QB3), University of California San Francisco, San Francisco, California, USA
| | - Dina Schneidman-Duhovny
- School of Computer Science and Engineering, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Torsten Schwede
- Biozentrum, University of Basel and SIB Swiss Institute of Bioinformatics, Basel, Switzerland
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory (EMBL) Hamburg, c/o DESY, Nokestrasse 85, 22607 Hamburg, Germany
| | - Masaaki Sugiyama
- Research Reactor Institute, Kyoto University, Kumatori, Sennan-gun, Osaka 590-0494, Japan
| | - John A. Tainer
- Basic Science Research Division, Molecular and Cellular Oncology, MD Anderson Cancer Center, University of Texas, Houston, Texas, USA
| | - Patrice Vachette
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Bâtiment 430, Université Paris-Sud, 91405 Orsay CEDEX, France
| | - John Westbrook
- Department of Chemistry and Chemical Biology, Rutgers University, New Brunswick, NJ 07102, USA
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23
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Orchestrated Domain Movement in Catalysis by Cytochrome P450 Reductase. Sci Rep 2017; 7:9741. [PMID: 28852004 PMCID: PMC5575293 DOI: 10.1038/s41598-017-09840-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 07/31/2017] [Indexed: 12/16/2022] Open
Abstract
NADPH-cytochrome P450 reductase is a multi-domain redox enzyme which is a key component of the P450 mono-oxygenase drug-metabolizing system. We report studies of the conformational equilibrium of this enzyme using small-angle neutron scattering, under conditions where we are able to control the redox state of the enzyme precisely. Different redox states have a profound effect on domain orientation in the enzyme and we analyse the data in terms of a two-state equilibrium between compact and extended conformations. The effects of ionic strength show that the presence of a greater proportion of the extended form leads to an enhanced ability to transfer electrons to cytochrome c. Domain motion is intrinsically linked to the functionality of the enzyme, and we can define the position of the conformational equilibrium for individual steps in the catalytic cycle.
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24
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Patel S, Sasidhar YU, Chary KVR. Mechanism of Initiation, Association, and Formation of Amyloid Fibrils Modeled with the N-Terminal Peptide Fragment, IKYLEFIS, of Myoglobin G-Helix. J Phys Chem B 2017; 121:7536-7549. [PMID: 28707888 DOI: 10.1021/acs.jpcb.7b02205] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Some peptides and proteins undergo self-aggregation under certain conditions, leading to amyloid fibrils formation, which is related to many disease conditions. It is important to understand such amyloid fibrils formation to provide mechanistic detail that governs the process. A predominantly α-helical myoglobin has been reported recently to readily form amyloid fibrils at a higher temperature, similar to its G-helix segment. Here, we have investigated the mechanism of amyloid fibrils formation by performing multiple long molecular dynamics simulations (27 μs) on the N-terminal segment of the G-helix of myoglobin. These simulations resulted in the formation of a single-layered tetrameric β-sheet with mixed parallel and antiparallel β-strands and this is the most common event irrespective of many different starting structures. Formation of the single-layered tetrameric β-sheet takes place following three distinctive pathways. The process of fibril initiation is dependent on temperature. Further, this study provides mechanistic insights into the formation of multilayered fibrilar structure, which could be applicable to a wider variety of peptides or proteins to understand the amyloidogenesis.
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Affiliation(s)
- Sunita Patel
- Tata Institute of Fundamental Research, Center for Interdisciplinary Sciences , Hyderabad 500075, India.,UM-DAE Centre for Excellence in Basic Sciences , Mumbai University Campus, Mumbai 400098, India
| | - Yellamraju U Sasidhar
- Department of Chemistry, Indian Institute of Technology Bombay , Mumbai 400076, India
| | - Kandala V R Chary
- Tata Institute of Fundamental Research, Center for Interdisciplinary Sciences , Hyderabad 500075, India.,Tata Institute of Fundamental Research , Mumbai 400005, India
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25
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Stamogiannos A, Maben Z, Papakyriakou A, Mpakali A, Kokkala P, Georgiadis D, Stern LJ, Stratikos E. Critical Role of Interdomain Interactions in the Conformational Change and Catalytic Mechanism of Endoplasmic Reticulum Aminopeptidase 1. Biochemistry 2017; 56:1546-1558. [PMID: 28218509 DOI: 10.1021/acs.biochem.6b01170] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Endoplasmic reticulum aminopeptidase 1 (ERAP1) is an intracellular enzyme that is important for the generation of antigenic epitopes and major histocompatibility class I-restricted adaptive immune responses. ERAP1 processes a vast variety of different peptides but still shows length and sequence selectivity, although the mechanism behind these properties is poorly understood. X-ray crystallographic analysis has revealed that ERAP1 can assume at least two distinct conformations in which C-terminal domain IV is either proximal or distal to active site domain II. To improve our understanding of the role of this conformational change in the catalytic mechanism of ERAP1, we used site-directed mutagenesis to perturb key salt bridges between domains II and IV. Enzymatic analysis revealed that these mutations, although located away from the catalytic site, greatly reduce the catalytic efficiency and change the allosteric kinetic behavior. The variants were more efficiently activated by small peptides and bound a competitive inhibitor with weaker affinity and faster dissociation kinetics. Molecular dynamics analysis suggested that the mutations affect the conformational distribution of ERAP1, reducing the population of closed states. Small-angle X-ray scattering indicated that both the wild type and the ERAP1 variants are predominantly in an open conformational state in solution. Overall, our findings suggest that electrostatic interactions between domains II and IV in ERAP1 are crucial for driving a conformational change that regulates the structural integrity of the catalytic site. The extent of domain opening in ERAP1 probably underlies its specialization for antigenic peptide precursors and should be taken into account in inhibitor development efforts.
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Affiliation(s)
| | - Zachary Maben
- Department of Pathology, University of Massachusetts Medical School , Worcester, Massachusetts 01655, United States
| | | | - Anastasia Mpakali
- National Centre for Scientific Research Demokritos , Agia Paraskevi, 15341 Athens, Greece
| | - Paraskevi Kokkala
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens , Panepistimiopolis, Zografou, 15771 Athens, Greece
| | - Dimitris Georgiadis
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens , Panepistimiopolis, Zografou, 15771 Athens, Greece
| | - Lawrence J Stern
- Department of Pathology, University of Massachusetts Medical School , Worcester, Massachusetts 01655, United States
| | - Efstratios Stratikos
- National Centre for Scientific Research Demokritos , Agia Paraskevi, 15341 Athens, Greece
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26
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Raghuwanshi B, Pehlajani NK, Sinha MK, Tripathy S. A retrospective study of transfusion practices in a Tertiary Care Institute. Indian J Anaesth 2017; 61:24-28. [PMID: 28216700 PMCID: PMC5296802 DOI: 10.4103/0019-5049.198395] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND AND AIMS Excessive requests for cross matching blood which is more than the blood required for transfusion are usually based on worst case assumptions leading to overestimation of blood usage. We investigated the blood ordering pattern and transfusion practices so as to incorporate a blood ordering schedule for streamlining the use of blood in various hospital departments. METHODS The study was conducted over a period of 19 months in a 350 bedded tertiary teaching hospital. Source of data was blood bank requisition forms and blood bank registers of patients who underwent elective or emergency procedures in the hospital, for which blood was ordered. Data were entered in MS Excel and analysed using SPSS version 20. RESULTS The blood bank was requested to prepare 10,594 units of blood for 2556 patients. The blood utilised was 16.04% of total cross matched blood, leaving 83.9% of units cross matched but not transfused to patient for whom it was prepared, i.e., wasted. The surgery department had the highest number of units cross matched and transfused. The least number of units cross matched and wasted due to non-transfusion were from the Department of Oncology. CONCLUSION The current deficiency of explicit maximum blood order schedule in our hospital is the major factor responsible for high cross match: transfusion ratio. Therefore, a maximal surgical blood order schedule has been suggested to the hospital transfusion committee to implement maximum surgical blood order schedules for selected procedures.
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Affiliation(s)
- Babita Raghuwanshi
- Department of Transfusion Medicine and Blood Bank, AIIMS, Bhubaneswar, Odisha, India
| | - N K Pehlajani
- Department of Pathology, L.N. Medical College, Bhopal, Madhya Pradesh, India
| | | | - Swagata Tripathy
- Department of Anaesthesiology, AIIMS, Bhubaneswar, Odisha, India
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27
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Brookes E, Vachette P, Rocco M, Pérez J. US-SOMO HPLC-SAXS module: dealing with capillary fouling and extraction of pure component patterns from poorly resolved SEC-SAXS data. J Appl Crystallogr 2016; 49:1827-1841. [PMID: 27738419 PMCID: PMC5045733 DOI: 10.1107/s1600576716011201] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 07/10/2016] [Indexed: 11/23/2022] Open
Abstract
The US-SOMO HPLC-SAXS (high-performance liquid chromatography coupled with small-angle X-ray scattering) module is an advanced tool for the comprehensive analysis of SEC-SAXS (size-exclusion chromatography coupled with SAXS) data. It includes baseline and band-broadening correction routines, and Gaussian decomposition of overlapping skewed peaks into pure components. Size-exclusion chromatography coupled with SAXS (small-angle X-ray scattering), often performed using a flow-through capillary, should allow direct collection of monodisperse sample data. However, capillary fouling issues and non-baseline-resolved peaks can hamper its efficacy. The UltraScan solution modeler (US-SOMO) HPLC-SAXS (high-performance liquid chromatography coupled with SAXS) module provides a comprehensive framework to analyze such data, starting with a simple linear baseline correction and symmetrical Gaussian decomposition tools [Brookes, Pérez, Cardinali, Profumo, Vachette & Rocco (2013 ▸). J. Appl. Cryst.46, 1823–1833]. In addition to several new features, substantial improvements to both routines have now been implemented, comprising the evaluation of outcomes by advanced statistical tools. The novel integral baseline-correction procedure is based on the more sound assumption that the effect of capillary fouling on scattering increases monotonically with the intensity scattered by the material within the X-ray beam. Overlapping peaks, often skewed because of sample interaction with the column matrix, can now be accurately decomposed using non-symmetrical modified Gaussian functions. As an example, the case of a polydisperse solution of aldolase is analyzed: from heavily convoluted peaks, individual SAXS profiles of tetramers, octamers and dodecamers are extracted and reliably modeled.
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Affiliation(s)
- Emre Brookes
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3901, USA
| | - Patrice Vachette
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, F-91198, France
| | - Mattia Rocco
- Biopolimeri e Proteomica, IRCCS AOU San Martino-IST, Istituto Nazionale per la Ricerca sul Cancro, Largo R. Benzi 10, Genova, I-16132, Italy
| | - Javier Pérez
- SWING Beamline, Synchrotron SOLEIL, L'Orme des Merisiers, BP48, Saint-Aubin, Gif-sur-Yvette, F-91192, France
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28
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Petrvalska O, Kosek D, Kukacka Z, Tosner Z, Man P, Vecer J, Herman P, Obsilova V, Obsil T. Structural Insight into the 14-3-3 Protein-dependent Inhibition of Protein Kinase ASK1 (Apoptosis Signal-regulating kinase 1). J Biol Chem 2016; 291:20753-65. [PMID: 27514745 DOI: 10.1074/jbc.m116.724310] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Indexed: 11/06/2022] Open
Abstract
Apoptosis signal-regulating kinase 1 (ASK1, also known as MAP3K5), a member of the mitogen-activated protein kinase kinase kinase (MAP3K) family, regulates diverse physiological processes. The activity of ASK1 is triggered by various stress stimuli and is involved in the pathogenesis of cancer, neurodegeneration, inflammation, and diabetes. ASK1 forms a high molecular mass complex whose activity is, under non-stress conditions, suppressed through interaction with thioredoxin and the scaffolding protein 14-3-3. The 14-3-3 protein binds to the phosphorylated Ser-966 motif downstream of the ASK1 kinase domain. The role of 14-3-3 in the inhibition of ASK1 has yet to be elucidated. In this study we performed structural analysis of the complex between the ASK1 kinase domain phosphorylated at Ser-966 (pASK1-CD) and the 14-3-3ζ protein. Small angle x-ray scattering (SAXS) measurements and chemical cross-linking revealed that the pASK1-CD·14-3-3ζ complex is dynamic and conformationally heterogeneous. In addition, structural analysis coupled with the results of phosphorus NMR and time-resolved tryptophan fluorescence measurements suggest that 14-3-3ζ interacts with the kinase domain of ASK1 in close proximity to its active site, thus indicating this interaction might block its accessibility and/or affect its conformation.
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Affiliation(s)
- Olivia Petrvalska
- From the Department of Physical and Macromolecular Chemistry, Faculty of Science, and Institute of Physiology and
| | - Dalibor Kosek
- From the Department of Physical and Macromolecular Chemistry, Faculty of Science, and Institute of Physiology and
| | - Zdenek Kukacka
- the Institute of Microbiology, The Czech Academy of Sciences, 14220 Prague, and
| | - Zdenek Tosner
- From the Department of Physical and Macromolecular Chemistry, Faculty of Science, and
| | - Petr Man
- the Institute of Microbiology, The Czech Academy of Sciences, 14220 Prague, and Department of Biochemistry, Faculty of Science, Charles University in Prague, 12843 Prague
| | - Jaroslav Vecer
- the Institute of Physics, Faculty of Mathematics and Physics, Charles University in Prague, 12116 Prague, Czech Republic
| | - Petr Herman
- the Institute of Physics, Faculty of Mathematics and Physics, Charles University in Prague, 12116 Prague, Czech Republic
| | | | - Tomas Obsil
- From the Department of Physical and Macromolecular Chemistry, Faculty of Science, and Institute of Physiology and
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29
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Vestergaard B. Analysis of biostructural changes, dynamics, and interactions – Small-angle X-ray scattering to the rescue. Arch Biochem Biophys 2016; 602:69-79. [DOI: 10.1016/j.abb.2016.02.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 02/17/2016] [Accepted: 02/26/2016] [Indexed: 12/27/2022]
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30
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LoPiccolo J, Kim SJ, Shi Y, Wu B, Wu H, Chait BT, Singer RH, Sali A, Brenowitz M, Bresnick AR, Backer JM. Assembly and Molecular Architecture of the Phosphoinositide 3-Kinase p85α Homodimer. J Biol Chem 2015; 290:30390-405. [PMID: 26475863 DOI: 10.1074/jbc.m115.689604] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Indexed: 11/06/2022] Open
Abstract
Phosphoinositide 3-kinases (PI3Ks) are a family of lipid kinases that are activated by growth factor and G-protein-coupled receptors and propagate intracellular signals for growth, survival, proliferation, and metabolism. p85α, a modular protein consisting of five domains, binds and inhibits the enzymatic activity of class IA PI3K catalytic subunits. Here, we describe the structural states of the p85α dimer, based on data from in vivo and in vitro solution characterization. Our in vitro assembly and structural analyses have been enabled by the creation of cysteine-free p85α that is functionally equivalent to native p85α. Analytical ultracentrifugation studies showed that p85α undergoes rapidly reversible monomer-dimer assembly that is highly exothermic in nature. In addition to the documented SH3-PR1 dimerization interaction, we identified a second intermolecular interaction mediated by cSH2 domains at the C-terminal end of the polypeptide. We have demonstrated in vivo concentration-dependent dimerization of p85α using fluorescence fluctuation spectroscopy. Finally, we have defined solution conditions under which the protein is predominantly monomeric or dimeric, providing the basis for small angle x-ray scattering and chemical cross-linking structural analysis of the discrete dimer. These experimental data have been used for the integrative structure determination of the p85α dimer. Our study provides new insight into the structure and assembly of the p85α homodimer and suggests that this protein is a highly dynamic molecule whose conformational flexibility allows it to transiently associate with multiple binding proteins.
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Affiliation(s)
| | - Seung Joong Kim
- the Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, and California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California 94158, and
| | - Yi Shi
- the Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York 10065
| | - Bin Wu
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Haiyan Wu
- From the Department of Molecular Pharmacology
| | - Brian T Chait
- the Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York 10065
| | - Robert H Singer
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Andrej Sali
- the Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, and California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California 94158, and
| | | | | | - Jonathan M Backer
- From the Department of Molecular Pharmacology, Department of Biochemistry,
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