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Omori NE, Bobitan AD, Vamvakeros A, Beale AM, Jacques SDM. Recent developments in X-ray diffraction/scattering computed tomography for materials science. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20220350. [PMID: 37691470 PMCID: PMC10493554 DOI: 10.1098/rsta.2022.0350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 07/17/2023] [Indexed: 09/12/2023]
Abstract
X-ray diffraction/scattering computed tomography (XDS-CT) methods are a non-destructive class of chemical imaging techniques that have the capacity to provide reconstructions of sample cross-sections with spatially resolved chemical information. While X-ray diffraction CT (XRD-CT) is the most well-established method, recent advances in instrumentation and data reconstruction have seen greater use of related techniques like small angle X-ray scattering CT and pair distribution function CT. Additionally, the adoption of machine learning techniques for tomographic reconstruction and data analysis are fundamentally disrupting how XDS-CT data is processed. The following narrative review highlights recent developments and applications of XDS-CT with a focus on studies in the last five years. This article is part of the theme issue 'Exploring the length scales, timescales and chemistry of challenging materials (Part 2)'.
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Affiliation(s)
- Naomi E. Omori
- Finden Limited, Merchant House, 5 East St Helens Street,Abingdon OX14 5EG, UK
| | - Antonia D. Bobitan
- Finden Limited, Merchant House, 5 East St Helens Street,Abingdon OX14 5EG, UK
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0FA, UK
| | - Antonis Vamvakeros
- Finden Limited, Merchant House, 5 East St Helens Street,Abingdon OX14 5EG, UK
- Dyson School of Design Engineering, Imperial College London, London SW7 2DB, UK
| | - Andrew M. Beale
- Finden Limited, Merchant House, 5 East St Helens Street,Abingdon OX14 5EG, UK
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0FA, UK
| | - Simon D. M. Jacques
- Finden Limited, Merchant House, 5 East St Helens Street,Abingdon OX14 5EG, UK
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2
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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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3
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Hutin S, Guillotin A, Zubieta C, Tully MD. Structural characterization of protein-DNA complexes using small angle X-ray scattering (SAXS) with contrast variation. Methods Enzymol 2023; 680:163-194. [PMID: 36710010 DOI: 10.1016/bs.mie.2022.08.021] [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: 02/01/2023]
Abstract
Molecular and atomic level characterization of transcription factor (TF)-DNA complexes is critical for understanding DNA-binding specificity and potentially structural changes that may occur in protein and/or DNA upon complex formation. Often TFs are large, multidomain proteins or contain disordered regions that contribute to DNA recognition and/or binding affinity but are difficult to structurally characterize due to their high molecular weight and intrinsic flexibility. This results in challenges to obtaining high resolution structural information using Nuclear Magnetic Resonance (NMR) spectroscopy due to the relatively large size of the protein-DNA complexes of interest or macromolecular crystallography due to the difficulty in obtaining crystals of flexible proteins. Small angle X-ray scattering (SAXS) offers a complementary method to NMR and X-ray crystallography that allows for low-resolution structural characterization of protein, DNA, and protein-DNA complexes in solution over a greater size range and irrespective of interdomain flexibility and/or disordered regions. One important caveat to SAXS data interpretation, however, has been the inability to distinguish between scattering coming from the protein versus DNA component of the complex of interest. Here, we present a protocol using contrast variation via increasing sucrose concentrations to distinguish between protein and DNA using the model protein bovine serum albumin (BSA) and DNA and the LUX ARRYTHMO TF-DNA complex. Examination of the scattering curves of the components individually and in combination with contrast variation allows the differentiation of protein and DNA density in the derived models. This protocol is designed for use on high flux SAXS beamlines with temperature-controlled sample storage and sample exposure units.
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Affiliation(s)
- Stephanie Hutin
- Laboratoire Physiologie Cellulaire et Végétale, Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG-DBSCI-LPCV, Grenoble, France
| | - Audrey Guillotin
- Laboratoire Physiologie Cellulaire et Végétale, Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG-DBSCI-LPCV, Grenoble, France
| | - Chloe Zubieta
- Laboratoire Physiologie Cellulaire et Végétale, Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG-DBSCI-LPCV, Grenoble, France.
| | - Mark D Tully
- European Synchrotron Radiation Facility, Structural Biology Group, Grenoble, France.
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4
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A comprehensive review of methods to study lncRNA-protein interactions in solution. Biochem Soc Trans 2022; 50:1415-1426. [PMID: 36250427 DOI: 10.1042/bst20220604] [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: 08/09/2022] [Revised: 09/10/2022] [Accepted: 09/27/2022] [Indexed: 11/17/2022]
Abstract
The long non-coding RNAs (lncRNAs) other than rRNA and tRNA were earlier assumed to be 'junk genomic material'. However, recent advancements in genomics methods have highlighted their roles not only in housekeeping but also in the progression of diseases like cancer as well as viral infections. lncRNAs owing to their length, have both short-range and long-range interactions resulting in complex folded structures that recruit various biomolecules enabling lncRNAs to undertake their various biological functions. Using cell lysate pull-down assays increasing number of lnRNAs-interacting proteins are being identified. These interactions can be further exploited to develop targeted novel therapeutic strategies to inhibit lncRNA-protein interactions. This review attempts to succinctly techniques that can identify and characterize the lnRNAs-protein interactions (i.e. affinity, stoichiometry, and thermodynamics). Furthermore, using other sophisticated biophysical techniques, one can also perform size estimations, and determine low-resolution structures. Since these methods study the biomolecules in solution, large-scale structural observations can be performed in real-time. This review attempts to briefly introduce the readers to biochemical and biophysical techniques, such that they can utilize these methods to obtain a holistic characterization of the biomolecules of interest. Additionally, it should be noted that the use of these methods is not limited to the characterization of the interacting molecules but can also be used to determine the efficacy of the therapeutic molecules to disrupt these interactions.
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Gallardo A, Bogart BM, Dutagaci B. Protein-Nucleic Acid Interactions for RNA Polymerase II Elongation Factors by Molecular Dynamics Simulations. J Chem Inf Model 2022; 62:3079-3089. [PMID: 35686985 DOI: 10.1021/acs.jcim.2c00121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
RNA polymerase II (Pol II) forms a complex with elongation factors to proceed to the elongation stage of the transcription process. In this work, we studied the elongation factor SPT5 and explored the protein-nucleic acid interactions for the isolated systems of KOW1 and KOW4 domains of SPT5 with DNA and RNA, respectively. We performed molecular dynamics (MD) simulations using three commonly used force fields that are CHARMM c36m, AMBER ff14sb, and ff19sb. Simulations showed strong protein-nucleic acid interactions and low electrostatic binding free energies for all force fields used. RNA was found to be highly dynamic with all force fields, while DNA had relatively more stable conformations with the AMBER force fields compared to that with CHARMM. Furthermore, we performed MD simulations of the complete elongation complex using CHARMM c36m and AMBER ff19sb force fields to compare the dynamics and interactions with the isolated systems. Similarly, strong KOW1 and DNA interactions were observed in the complete elongation complex simulations and DNA was further stabilized by a network of interactions involving SPT5-KOW1, SPT4, and rpb2 of Pol II. Overall, our study showed that the differences between CHARMM and AMBER force fields strongly affect the dynamics of the nucleic acids. CHARMM provides highly flexible DNA, while AMBER largely stabilizes the DNA structure. Although the presence of the entire interaction network stabilized the DNA and decreased the differences in the results from the two force fields, the discrepancies of the force fields for smaller systems may reflect their problems in generating accurate dynamics of nucleic acids.
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Affiliation(s)
- Adan Gallardo
- Department of Molecular and Cell Biology, University of California, Merced, 5200 North Lake Road, Merced, California 95343, United States
| | - Brandon M Bogart
- Department of Molecular and Cell Biology, University of California, Merced, 5200 North Lake Road, Merced, California 95343, United States
| | - Bercem Dutagaci
- Department of Molecular and Cell Biology, University of California, Merced, 5200 North Lake Road, Merced, California 95343, United States
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Ling JA, Frevert Z, Washington MT. Recent Advances in Understanding the Structures of Translesion Synthesis DNA Polymerases. Genes (Basel) 2022; 13:genes13050915. [PMID: 35627300 PMCID: PMC9141541 DOI: 10.3390/genes13050915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/16/2022] [Accepted: 05/19/2022] [Indexed: 12/10/2022] Open
Abstract
DNA damage in the template strand causes replication forks to stall because replicative DNA polymerases are unable to efficiently incorporate nucleotides opposite template DNA lesions. To overcome these replication blocks, cells are equipped with multiple translesion synthesis polymerases that have evolved specifically to incorporate nucleotides opposite DNA lesions. Over the past two decades, X-ray crystallography has provided a wealth of information about the structures and mechanisms of translesion synthesis polymerases. This approach, however, has been limited to ground state structures of these polymerases bound to DNA and nucleotide substrates. Three recent methodological developments have extended our understanding of the structures and mechanisms of these polymerases. These include time-lapse X-ray crystallography, which allows one to identify novel reaction intermediates; full-ensemble hybrid methods, which allow one to examine the conformational flexibility of the intrinsically disordered regions of proteins; and cryo-electron microscopy, which allows one to determine the high-resolution structures of larger protein complexes. In this article, we will discuss how these three methodological developments have added to our understanding of the structures and mechanisms of translesion synthesis polymerases.
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Bimetallic Copper/Ruthenium/Osmium Complexes: Observation of Conformational Differences Between the Solution Phase and Solid State by Atomic Pair Distribution Function Analysis. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202111764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Chinnam NB, Syed A, Burnett KH, Hura GL, Tainer JA, Tsutakawa SE. Universally Accessible Structural Data on Macromolecular Conformation, Assembly, and Dynamics by Small Angle X-Ray Scattering for DNA Repair Insights. Methods Mol Biol 2022; 2444:43-68. [PMID: 35290631 PMCID: PMC9020468 DOI: 10.1007/978-1-0716-2063-2_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Structures provide a critical breakthrough step for biological analyses, and small angle X-ray scattering (SAXS) is a powerful structural technique to study dynamic DNA repair proteins. As toxic and mutagenic repair intermediates need to be prevented from inadvertently harming the cell, DNA repair proteins often chaperone these intermediates through dynamic conformations, coordinated assemblies, and allosteric regulation. By measuring structural conformations in solution for both proteins, DNA, RNA, and their complexes, SAXS provides insight into initial DNA damage recognition, mechanisms for validation of their substrate, and pathway regulation. Here, we describe exemplary SAXS analyses of a DNA damage response protein spanning from what can be derived directly from the data to obtaining super resolution through the use of SAXS selection of atomic models. We outline strategies and tactics for practical SAXS data collection and analysis. Making these structural experiments in reach of any basic and clinical researchers who have protein, SAXS data can readily be collected at government-funded synchrotrons, typically at no cost for academic researchers. In addition to discussing how SAXS complements and enhances cryo-electron microscopy, X-ray crystallography, NMR, and computational modeling, we furthermore discuss taking advantage of recent advances in protein structure prediction in combination with SAXS analysis.
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Affiliation(s)
- Naga Babu Chinnam
- Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Aleem Syed
- Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Kathryn H Burnett
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Greg L Hura
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Chemistry and Biochemistry Department, University of California Santa Cruz, Santa Cruz, CA, USA
| | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Susan E Tsutakawa
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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9
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Xie ZL, Liu X, Valentine AJS, Lynch VM, Tiede DM, Li X, Mulfort KL. Bimetallic Copper/Ruthenium/Osmium Complexes: Observation of Conformational Differences Between the Solution Phase and Solid State by Atomic Pair Distribution Function Analysis. Angew Chem Int Ed Engl 2021; 61:e202111764. [PMID: 34788495 DOI: 10.1002/anie.202111764] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/26/2021] [Indexed: 11/10/2022]
Abstract
High-energy X-ray scattering and pair distribution function analysis (HEXS/PDF) is a powerful method to reveal the structure of materials lacking long-range order, but is underutilized for molecular complexes in solution. We demonstrate the application of HEXS/PDF with 0.26 Å resolution to uncover the solution structure of five bimetallic CuI /RuII /OsII complexes. HEXS/PDF of each complex in acetonitrile solution confirms the pairwise distances in the local coordination sphere of each metal center as well as the metal⋅⋅⋅metal distances separated by over 12 Å. The metal⋅⋅⋅metal distance detected in solution is compared with that from the crystal structure and molecular models to confirm that distortions to the metal bridging ligand are unique to the solid state. This work presents the first example of observing sub-Ångström conformational differences by direct comparison of solution phase and solid-state structures and shows the potential for HEXS/PDF in the determination of solution structure of single molecules.
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Affiliation(s)
- Zhu-Lin Xie
- Division of Chemical Sciences and Engineering, Argonne National Laboratory, 9700 S Cass Ave, Lemont, IL, 60439, USA
| | - Xiaolin Liu
- Department of Chemistry, University of Washington, 109 Bagley Hall, Seattle, WA, 98195-1700, USA
| | - Andrew J S Valentine
- Department of Chemistry, University of Washington, 109 Bagley Hall, Seattle, WA, 98195-1700, USA
| | - Vincent M Lynch
- Department of Chemistry, University of Texas at Austin, 105 E 24TH ST., Austin, TX, 78712-1224, USA
| | - David M Tiede
- Division of Chemical Sciences and Engineering, Argonne National Laboratory, 9700 S Cass Ave, Lemont, IL, 60439, USA
| | - Xiaosong Li
- Department of Chemistry, University of Washington, 109 Bagley Hall, Seattle, WA, 98195-1700, USA
| | - Karen L Mulfort
- Division of Chemical Sciences and Engineering, Argonne National Laboratory, 9700 S Cass Ave, Lemont, IL, 60439, USA
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10
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Hammel M, Tainer JA. X-ray scattering reveals disordered linkers and dynamic interfaces in complexes and mechanisms for DNA double-strand break repair impacting cell and cancer biology. Protein Sci 2021; 30:1735-1756. [PMID: 34056803 PMCID: PMC8376411 DOI: 10.1002/pro.4133] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 05/23/2021] [Accepted: 05/25/2021] [Indexed: 12/17/2022]
Abstract
Evolutionary selection ensures specificity and efficiency in dynamic metastable macromolecular machines that repair DNA damage without releasing toxic and mutagenic intermediates. Here we examine non‐homologous end joining (NHEJ) as the primary conserved DNA double‐strand break (DSB) repair process in human cells. NHEJ has exemplary key roles in networks determining the development, outcome of cancer treatments by DSB‐inducing agents, generation of antibody and T‐cell receptor diversity, and innate immune response for RNA viruses. We determine mechanistic insights into NHEJ structural biochemistry focusing upon advanced small angle X‐ray scattering (SAXS) results combined with X‐ray crystallography (MX) and cryo‐electron microscopy (cryo‐EM). SAXS coupled to atomic structures enables integrated structural biology for objective quantitative assessment of conformational ensembles and assemblies in solution, intra‐molecular distances, structural similarity, functional disorder, conformational switching, and flexibility. Importantly, NHEJ complexes in solution undergo larger allosteric transitions than seen in their cryo‐EM or MX structures. In the long‐range synaptic complex, X‐ray repair cross‐complementing 4 (XRCC4) plus XRCC4‐like‐factor (XLF) form a flexible bridge and linchpin for DNA ends bound to KU heterodimer (Ku70/80) and DNA‐PKcs (DNA‐dependent protein kinase catalytic subunit). Upon binding two DNA ends, auto‐phosphorylation opens DNA‐PKcs dimer licensing NHEJ via concerted conformational transformations of XLF‐XRCC4, XLF–Ku80, and LigIVBRCT–Ku70 interfaces. Integrated structures reveal multifunctional roles for disordered linkers and modular dynamic interfaces promoting DSB end processing and alignment into the short‐range complex for ligation by LigIV. Integrated findings define dynamic assemblies fundamental to designing separation‐of‐function mutants and allosteric inhibitors targeting conformational transitions in multifunctional complexes.
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Affiliation(s)
- Michal Hammel
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - John A Tainer
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California, USA.,Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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Covaceuszach S, Peche L, Konarev P, Lamba D. A combined evolutionary and structural approach to disclose the primary structural determinants essential for proneurotrophins biological functions. Comput Struct Biotechnol J 2021; 19:2891-2904. [PMID: 34094000 PMCID: PMC8144349 DOI: 10.1016/j.csbj.2021.05.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/03/2021] [Accepted: 05/03/2021] [Indexed: 12/24/2022] Open
Abstract
The neurotrophins, i.e., Nerve Growth Factor (NGF), Brain-Derived Neurotrophic Factor (BDNF), Neurotrophin 3 (NT3) and Neurotrophin 4 (NT4), are known to play a range of crucial functions in the developing and adult peripheral and central nervous systems. Initially synthesized as precursors, i.e., proneurotrophins (proNTs), that are cleaved to release C-terminal mature forms, they act through two types of receptors, the specific Trk receptors (Tropomyosin-related kinases) and the pan-neurotrophin receptor p75NTR, to initiate survival and differentiative responses. Recently, all the proNTs but proNT4 have been demonstrated to be not just inactive precursors, but signaling ligands that mediate opposing actions in fundamental aspects of the nervous system with respect to the mature counterparts through dual-receptor complexes formation with a member of the VPS10 family and p75NTR. Despite the functional relevance, the molecular determinants underpinning the interactions between the pro-domains and their receptors are still elusive probably due to their intrinsically disordered nature. Here we present an evolutionary approach coupled to an experimental study aiming to uncover the structural and dynamical basis of the biological function displayed by proNGF, proBDNF and proNT3 but missing in proNT4. A bioinformatic analysis allowed to elucidate the functional adaptability of the proNTs family in vertebrates, identifying conserved key structural features. The combined biochemical and SAXS experiments shed lights on the structure and dynamic behavior of the human proNTs in solution, giving insights on the evolutionary conserved structural motifs, essential for the multifaceted roles of proNTs in physiological as well as in pathological contexts.
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Affiliation(s)
- S. Covaceuszach
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Trieste, Italy
| | - L.Y. Peche
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Trieste, Italy
| | - P.V. Konarev
- A.V. Shubnikov Institute of Crystallography of Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Moscow, Russia
| | - D. Lamba
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Trieste, Italy
- Interuniversity Consortium “Biostructures and Biosystems National Institute”, Roma, Italy
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Hammel M, Rashid I, Sverzhinsky A, Pourfarjam Y, Tsai MS, Ellenberger T, Pascal JM, Kim IK, Tainer JA, Tomkinson AE. An atypical BRCT-BRCT interaction with the XRCC1 scaffold protein compacts human DNA Ligase IIIα within a flexible DNA repair complex. Nucleic Acids Res 2021; 49:306-321. [PMID: 33330937 PMCID: PMC7797052 DOI: 10.1093/nar/gkaa1188] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 11/21/2020] [Accepted: 12/13/2020] [Indexed: 01/08/2023] Open
Abstract
The XRCC1–DNA ligase IIIα complex (XL) is critical for DNA single-strand break repair, a key target for PARP inhibitors in cancer cells deficient in homologous recombination. Here, we combined biophysical approaches to gain insights into the shape and conformational flexibility of the XL as well as XRCC1 and DNA ligase IIIα (LigIIIα) alone. Structurally-guided mutational analyses based on the crystal structure of the human BRCT–BRCT heterodimer identified the network of salt bridges that together with the N-terminal extension of the XRCC1 C-terminal BRCT domain constitute the XL molecular interface. Coupling size exclusion chromatography with small angle X-ray scattering and multiangle light scattering (SEC-SAXS–MALS), we determined that the XL is more compact than either XRCC1 or LigIIIα, both of which form transient homodimers and are highly disordered. The reduced disorder and flexibility allowed us to build models of XL particles visualized by negative stain electron microscopy that predict close spatial organization between the LigIIIα catalytic core and both BRCT domains of XRCC1. Together our results identify an atypical BRCT–BRCT interaction as the stable nucleating core of the XL that links the flexible nick sensing and catalytic domains of LigIIIα to other protein partners of the flexible XRCC1 scaffold.
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Affiliation(s)
- Michal Hammel
- Molecular Biophysics & Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ishtiaque Rashid
- Departments of Internal Medicine, Molecular Genetics & Microbiology and the University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131, USA
| | - Aleksandr Sverzhinsky
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Yasin Pourfarjam
- Department of Chemistry, University of Cincinnati, 301 Clifton Ct, Cincinnati, OH 45221, USA
| | - Miaw-Sheue Tsai
- Molecular Biophysics & Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Tom Ellenberger
- Department of Biochemistry, Washington University, St. Louis, MO, USA
| | - John M Pascal
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec, Canada
| | - In-Kwon Kim
- Department of Chemistry, University of Cincinnati, 301 Clifton Ct, Cincinnati, OH 45221, USA
| | - John A Tainer
- Departments of Cancer Biology and Molecular & Cellular Oncology, University of Texas, MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Alan E Tomkinson
- Departments of Internal Medicine, Molecular Genetics & Microbiology and the University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131, USA
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In-solution structural studies involving a phospholipase A 2-like myotoxin and a natural inhibitor: Plasticity of oligomeric assembly affects mechanisms of inhibition. Biochimie 2020; 181:145-153. [PMID: 33333169 DOI: 10.1016/j.biochi.2020.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 12/11/2020] [Accepted: 12/12/2020] [Indexed: 02/02/2023]
Abstract
Snakebite envenomation has been categorized by World Health Organization as a category A neglected tropical disease, since it causes chronic psychological disorders, physical disablement and death. Ophidian accidents may cause local myonecrosis that cause drastic sequelae, which are not efficiently neutralized via serum therapy. Phospholipase A2-like (PLA2-like) myotoxins have a major role in the local effects caused by several snake venoms. We previously demonstrated that chicoric acid (CA) is an efficient inhibitor of the BthTX-I myotoxin and solved the X-ray structure of complex. Herein, we assess the oligomeric behavior of the BthTX-I/CA complex in solution under different physical-chemical conditions and using toxin obtained by two different biochemical methodologies to fully elucidate structural bases of inhibition of myotoxins by CA. We demonstrated the ability of PLA2-like proteins to form different oligomeric assemblies in the presence of certain inhibitors, which can also be modulated by buffer polarity change. In the presence of ethanol, BthTX-I/CA remains predominantly in a monomeric conformation, which prevents it from being in its active form (dimeric conformation). In contrast, in the absence of ethanol, the tetramer assembly was observed, which hid key regions of the protein responsible for docking and disruption of the muscle membrane. Therefore, the "plasticity" of these proteins with regard to their abilities to form oligomeric assemblies is a key issue for the future development of therapeutic agents to complement of serum therapy.
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14
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Prior C, Davies OR, Bruce D, Pohl E. Obtaining Tertiary Protein Structures by the ab Initio Interpretation of Small Angle X-ray Scattering Data. J Chem Theory Comput 2020; 16:1985-2001. [PMID: 32023061 PMCID: PMC7145352 DOI: 10.1021/acs.jctc.9b01010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
Small angle X-ray scattering (SAXS)
is an important tool for investigating
the structure of proteins in solution. We present a novel ab initio
method representing polypeptide chains as discrete curves used to
derive a meaningful three-dimensional model from only the primary sequence and SAXS data. High resolution structures were
used to generate probability density functions for each common secondary
structural element found in proteins, which are used to place realistic
restraints on the model curve’s geometry. This is coupled with
a novel explicit hydration shell model in order to derive physically
meaningful three-dimensional models by optimizing against experimental
SAXS data. The efficacy of this model is verified on an established
benchmark protein set, and then it is used to predict the lysozyme
structure using only its primary sequence and SAXS data. The method
is used to generate a biologically plausible model of the coiled-coil
component of the human synaptonemal complex central element protein.
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Affiliation(s)
- Christopher Prior
- Department of Mathematical Sciences, Durham University, Durham DH1 3LE, United Kingdom
| | - Owen R Davies
- Institute for Cell and Molecular Bioscience, Medical School, University of Newcastle, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Daniel Bruce
- Department of Biosciences Durham University, Durham DH1 3LE, United Kingdom.,Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Ehmke Pohl
- Department of Biosciences Durham University, Durham DH1 3LE, United Kingdom.,Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
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15
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Hura GL, Hodge CD, Rosenberg D, Guzenko D, Duarte JM, Monastyrskyy B, Grudinin S, Kryshtafovych A, Tainer JA, Fidelis K, Tsutakawa SE. Small angle X-ray scattering-assisted protein structure prediction in CASP13 and emergence of solution structure differences. Proteins 2019; 87:1298-1314. [PMID: 31589784 DOI: 10.1002/prot.25827] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 09/27/2019] [Accepted: 09/27/2019] [Indexed: 12/14/2022]
Abstract
Small angle X-ray scattering (SAXS) measures comprehensive distance information on a protein's structure, which can constrain and guide computational structure prediction algorithms. Here, we evaluate structure predictions of 11 monomeric and oligomeric proteins for which SAXS data were collected and provided to predictors in the 13th round of the Critical Assessment of protein Structure Prediction (CASP13). The category for SAXS-assisted predictions made gains in certain areas for CASP13 compared to CASP12. Improvements included higher quality data with size exclusion chromatography-SAXS (SEC-SAXS) and better selection of targets and communication of results by CASP organizers. In several cases, we can track improvements in model accuracy with use of SAXS data. For hard multimeric targets where regular folding algorithms were unsuccessful, SAXS data helped predictors to build models better resembling the global shape of the target. For most models, however, no significant improvement in model accuracy at the domain level was registered from use of SAXS data, when rigorously comparing SAXS-assisted models to the best regular server predictions. To promote future progress in this category, we identify successes, challenges, and opportunities for improved strategies in prediction, assessment, and communication of SAXS data to predictors. An important observation is that, for many targets, SAXS data were inconsistent with crystal structures, suggesting that these proteins adopt different conformation(s) in solution. This CASP13 result, if representative of PDB structures and future CASP targets, may have substantive implications for the structure training databases used for machine learning, CASP, and use of prediction models for biology.
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Affiliation(s)
- Greg L Hura
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California.,Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California
| | - Curtis D Hodge
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California
| | - Daniel Rosenberg
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California
| | - Dmytro Guzenko
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, San Diego Supercomputer Center, University of California, San Diego, La Jolla, California
| | - Jose M Duarte
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, San Diego Supercomputer Center, University of California, San Diego, La Jolla, California
| | - Bohdan Monastyrskyy
- Protein Structure Prediction Center, Genome and Biomedical Sciences Facilities, University of California, Davis, California
| | - Sergei Grudinin
- Univ. Grenoble Alpes, CNRS, Inria, Grenoble INP, LJK, 38000, Grenoble, France
| | - Andriy Kryshtafovych
- Protein Structure Prediction Center, Genome and Biomedical Sciences Facilities, University of California, Davis, California
| | - John A Tainer
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California.,Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
| | - Krzysztof Fidelis
- Protein Structure Prediction Center, Genome and Biomedical Sciences Facilities, University of California, Davis, California
| | - Susan E Tsutakawa
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California
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16
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Brosey CA, Tainer JA. Evolving SAXS versatility: solution X-ray scattering for macromolecular architecture, functional landscapes, and integrative structural biology. Curr Opin Struct Biol 2019; 58:197-213. [PMID: 31204190 PMCID: PMC6778498 DOI: 10.1016/j.sbi.2019.04.004] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 04/10/2019] [Accepted: 04/15/2019] [Indexed: 11/27/2022]
Abstract
Small-angle X-ray scattering (SAXS) has emerged as an enabling integrative technique for comprehensive analyses of macromolecular structures and interactions in solution. Over the past two decades, SAXS has become a mainstay of the structural biologist's toolbox, supplying multiplexed measurements of molecular shape and dynamics that unveil biological function. Here, we discuss evolving SAXS theory, methods, and applications that extend the field of small-angle scattering beyond simple shape characterization. SAXS, coupled with size-exclusion chromatography (SEC-SAXS) and time-resolved (TR-SAXS) methods, is now providing high-resolution insight into macromolecular flexibility and ensembles, delineating biophysical landscapes, and facilitating high-throughput library screening to assess macromolecular properties and to create opportunities for drug discovery. Looking forward, we consider SAXS in the integrative era of hybrid structural biology methods, its potential for illuminating cellular supramolecular and mesoscale structures, and its capacity to complement high-throughput bioinformatics sequencing data. As advances in the field continue, we look forward to proliferating uses of SAXS based upon its abilities to robustly produce mechanistic insights for biology and medicine.
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Affiliation(s)
- Chris A Brosey
- Molecular and Cellular Oncology and Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
| | - John A Tainer
- Molecular and Cellular Oncology and Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA; MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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17
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Bacolla A, Ye Z, Ahmed Z, Tainer JA. Cancer mutational burden is shaped by G4 DNA, replication stress and mitochondrial dysfunction. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 147:47-61. [PMID: 30880007 PMCID: PMC6745008 DOI: 10.1016/j.pbiomolbio.2019.03.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 03/08/2019] [Accepted: 03/12/2019] [Indexed: 02/01/2023]
Abstract
A hallmark of cancer is genomic instability, which can enable cancer cells to evade therapeutic strategies. Here we employed a computational approach to uncover mechanisms underlying cancer mutational burden by focusing upon relationships between 1) translocation breakpoints and the thousands of G4 DNA-forming sequences within retrotransposons impacting transcription and exemplifying probable non-B DNA structures and 2) transcriptome profiling and cancer mutations. We determined the location and number of G4 DNA-forming sequences in the Genome Reference Consortium Human Build 38 and found a total of 358,605 covering ∼13.4 million bases. By analyzing >97,000 unique translocation breakpoints from the Catalogue Of Somatic Mutations In Cancer (COSMIC), we found that breakpoints are overrepresented at G4 DNA-forming sequences within hominid-specific SVA retrotransposons, and generally occur in tumors with mutations in tumor suppressor genes, such as TP53. Furthermore, correlation analyses between mRNA levels and exome mutational loads from The Cancer Genome Atlas (TCGA) encompassing >450,000 gene-mutation regressions revealed strong positive and negative associations, which depended upon tissue of origin. The strongest positive correlations originated from genes not listed as cancer genes in COSMIC; yet, these show strong predictive power for survival in most tumor types by Kaplan-Meier estimation. Thus, correlation analyses of DNA structure and gene expression with mutation loads complement and extend more traditional approaches to elucidate processes shaping genomic instability in cancer. The combined results point to G4 DNA, activation of cell cycle/DNA repair pathways, and mitochondrial dysfunction as three major factors driving the accumulation of somatic mutations in cancer cells.
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Affiliation(s)
- Albino Bacolla
- Departments of Cancer Biology and of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA.
| | - Zu Ye
- Departments of Cancer Biology and of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA.
| | - Zamal Ahmed
- Departments of Cancer Biology and of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA.
| | - John A Tainer
- Departments of Cancer Biology and of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA.
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18
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Adamopoulos A, Heidebrecht T, Roosendaal J, Touw WG, Phan IQ, Beijnen J, Perrakis A. The domain architecture of the protozoan protein J-DNA-binding protein 1 suggests synergy between base J DNA binding and thymidine hydroxylase activity. J Biol Chem 2019; 294:12815-12825. [PMID: 31292194 DOI: 10.1074/jbc.ra119.007393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 07/04/2019] [Indexed: 11/06/2022] Open
Abstract
J-DNA-binding protein 1 (JBP1) contributes to the biosynthesis and maintenance of base J (β-d-glucosyl-hydroxymethyluracil), an epigenetic modification of thymidine (T) confined to pathogenic protozoa such as Trypanosoma and Leishmania JBP1 has two known functional domains: an N-terminal T hydroxylase (TH) homologous to the 5-methylcytosine hydroxylase domain in TET proteins and a J-DNA-binding domain (JDBD) that resides in the middle of JBP1. Here, we show that removing JDBD from JBP1 results in a soluble protein (Δ-JDBD) with the N- and C-terminal regions tightly associated together in a well-ordered structure. We found that this Δ-JDBD domain retains TH activity in vitro but displays a 15-fold lower apparent rate of hydroxylation compared with JBP1. Small-angle X-ray scattering (SAXS) experiments on JBP1 and JDBD in the presence or absence of J-DNA and on Δ-JDBD enabled us to generate low-resolution three-dimensional models. We conclude that Δ-JDBD, and not the N-terminal region of JBP1 alone, is a distinct folding unit. Our SAXS-based model supports the notion that binding of JDBD specifically to J-DNA can facilitate T hydroxylation 12-14 bp downstream on the complementary strand of the J-recognition site. We postulate that insertion of the JDBD module into the Δ-JDBD scaffold during evolution provided a mechanism that synergized J recognition and T hydroxylation, ensuring inheritance of base J in specific sequence patterns following DNA replication in kinetoplastid parasites.
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Affiliation(s)
- Athanassios Adamopoulos
- Department of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Tatjana Heidebrecht
- Department of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Jeroen Roosendaal
- Department of Clinical Pharmacology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Wouter G Touw
- Department of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Isabelle Q Phan
- Seattle Structural Genomics Center for Infectious Disease, Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington 98109
| | - Jos Beijnen
- Department of Clinical Pharmacology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Anastassis Perrakis
- Department of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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19
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Oliver RC, Rolband LA, Hutchinson-Lundy AM, Afonin KA, Krueger JK. Small-Angle Scattering as a Structural Probe for Nucleic Acid Nanoparticles (NANPs) in a Dynamic Solution Environment. NANOMATERIALS (BASEL, SWITZERLAND) 2019; 9:E681. [PMID: 31052508 PMCID: PMC6566709 DOI: 10.3390/nano9050681] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 04/16/2019] [Accepted: 04/19/2019] [Indexed: 12/23/2022]
Abstract
Nucleic acid-based technologies are an emerging research focus area for pharmacological and biological studies because they are biocompatible and can be designed to produce a variety of scaffolds at the nanometer scale. The use of nucleic acids (ribonucleic acid (RNA) and/or deoxyribonucleic acid (DNA)) as building materials in programming the assemblies and their further functionalization has recently established a new exciting field of RNA and DNA nanotechnology, which have both already produced a variety of different functional nanostructures and nanodevices. It is evident that the resultant architectures require detailed structural and functional characterization and that a variety of technical approaches must be employed to promote the development of the emerging fields. Small-angle X-ray and neutron scattering (SAS) are structural characterization techniques that are well placed to determine the conformation of nucleic acid nanoparticles (NANPs) under varying solution conditions, thus allowing for the optimization of their design. SAS experiments provide information on the overall shapes and particle dimensions of macromolecules and are ideal for following conformational changes of the molecular ensemble as it behaves in solution. In addition, the inherent differences in the neutron scattering of nucleic acids, lipids, and proteins, as well as the different neutron scattering properties of the isotopes of hydrogen, combined with the ability to uniformly label biological macromolecules with deuterium, allow one to characterize the conformations and relative dispositions of the individual components within an assembly of biomolecules. This article will review the application of SAS methods and provide a summary of their successful utilization in the emerging field of NANP technology to date, as well as share our vision on its use in complementing a broad suite of structural characterization tools with some simulated results that have never been shared before.
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Affiliation(s)
- Ryan C Oliver
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
| | - Lewis A Rolband
- UNC Charlotte Chemistry Department, Charlotte, NC 28223, USA.
| | | | - Kirill A Afonin
- UNC Charlotte Chemistry Department, Charlotte, NC 28223, USA.
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20
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Powers KT, Gildenberg MS, Washington MT. Modeling Conformationally Flexible Proteins With X-ray Scattering and Molecular Simulations. Comput Struct Biotechnol J 2019; 17:570-578. [PMID: 31073392 PMCID: PMC6495069 DOI: 10.1016/j.csbj.2019.04.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 04/15/2019] [Accepted: 04/17/2019] [Indexed: 01/03/2023] Open
Abstract
Proteins and protein complexes with high conformational flexibility participate in a wide range of biological processes. These processes include genome maintenance, gene expression, signal transduction, cell cycle regulation, and many others. Gaining a structural understanding of conformationally flexible proteins and protein complexes is arguably the greatest problem facing structural biologists today. Over the last decade, some progress has been made toward understanding the conformational flexibility of such systems using hybrid approaches. One particularly fruitful strategy has been the combination of small-angle X-ray scattering (SAXS) and molecular simulations. In this article, we provide a brief overview of SAXS and molecular simulations and then discuss two general approaches for combining SAXS data and molecular simulations: minimal ensemble approaches and full ensemble approaches. In minimal ensemble approaches, one selects a minimal ensemble of structures from the simulations that best fit the SAXS data. In full ensemble approaches, one validates a full ensemble of structures from the simulations using SAXS data. We argue that full ensemble models are more realistic than minimal ensemble searches models and that full ensemble approaches should be used wherever possible.
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Key Words
- BD, Brownian dynamics
- CG, coarse-grained
- Cryo-EM, cryo-electron microscopy
- DNA polymerase
- DNA replication
- Dmax, maximal distance
- LD, Langevin dynamics
- MD, molecular dynamics
- Minimal ensemble search
- NMR, nuclear magnetic resonance
- PCNA, proliferating cell nuclear antigen
- Pol η, DNA polymerase eta
- Protein structure
- RPA, replication protein A
- Rg, radius of gyration
- SANS
- SANS, small-angle neutron scattering
- SAXS
- SAXS, small-angle X-ray scattering
- SEC, size exclusion chromatography
- SUMO, small ubiquitin-like modifie
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Affiliation(s)
| | | | - M. Todd Washington
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242-1109, United States of America
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21
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Abstract
Binding of calcium - and small molecules in general - often induce conformational changes in large molecules and complexes. The degree and type of change varies, but the resulting shift in specific affinities ultimately induces a physiological response. It is therefore important for our understanding of responses at the cellular level to define coupled changes at the molecular level.Calumenin, a six-EF-hand calcium-binding protein localized in the endoplasmic reticulum, undergoes substantial calcium-induced rearrangement. We have demonstrated how calumenin changes from being unfolded in the absence of calcium to a compact trilobal fold in the presence of calcium (Mazzorana et al., PLoS One 11:e0151547, 2016).Here, we describe protocols for the expression and purification of calumenin and calmodulin, another EF-hand protein modulated by calcium, along with protocols for biophysical techniques used to characterize calcium-induced changes to protein conformation. Analytical size-exclusion chromatography in the presence and absence of calcium provides an informed indication of any larger conformational movements. Circular dichroism spectroscopy reveals alterations to the secondary or tertiary structure, while small-angle X-ray scattering explores changes further providing low-resolution conformational details.Surface plasmon resonance estimates binding kinetics and affinities completing the biophysical description of these events.
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Affiliation(s)
- Marco Mazzorana
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
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22
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Potrzebowski W, Trewhella J, Andre I. Bayesian inference of protein conformational ensembles from limited structural data. PLoS Comput Biol 2018; 14:e1006641. [PMID: 30557358 PMCID: PMC6312354 DOI: 10.1371/journal.pcbi.1006641] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/31/2018] [Accepted: 11/13/2018] [Indexed: 11/21/2022] Open
Abstract
Many proteins consist of folded domains connected by regions with higher flexibility. The details of the resulting conformational ensemble play a central role in controlling interactions between domains and with binding partners. Small-Angle Scattering (SAS) is well-suited to study the conformational states adopted by proteins in solution. However, analysis is complicated by the limited information content in SAS data and care must be taken to avoid constructing overly complex ensemble models and fitting to noise in the experimental data. To address these challenges, we developed a method based on Bayesian statistics that infers conformational ensembles from a structural library generated by all-atom Monte Carlo simulations. The first stage of the method involves a fast model selection based on variational Bayesian inference that maximizes the model evidence of the selected ensemble. This is followed by a complete Bayesian inference of population weights in the selected ensemble. Experiments with simulated ensembles demonstrate that model evidence is capable of identifying the correct ensemble and that correct number of ensemble members can be recovered up to high level of noise. Using experimental data, we demonstrate how the method can be extended to include data from Nuclear Magnetic Resonance (NMR) and structural energies of conformers extracted from the all-atom energy functions. We show that the data from SAXS, NMR chemical shifts and energies calculated from conformers can work synergistically to improve the definition of the conformational ensemble.
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Affiliation(s)
- Wojciech Potrzebowski
- Data Management and Software Centre, European Spallation Source ERIC, Copenhagen, Denmark
- Biochemistry and Structural Biology, University of Lund, Lund, Sweden
| | - Jill Trewhella
- School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia
| | - Ingemar Andre
- Biochemistry and Structural Biology, University of Lund, Lund, Sweden
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23
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Chen YL, Lee T, Elber R, Pollack L. Conformations of an RNA Helix-Junction-Helix Construct Revealed by SAXS Refinement of MD Simulations. Biophys J 2018; 116:19-30. [PMID: 30558889 DOI: 10.1016/j.bpj.2018.11.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 11/02/2018] [Accepted: 11/12/2018] [Indexed: 10/27/2022] Open
Abstract
RNA is involved in a broad range of biological processes that extend far beyond translation. Many of RNA's recently discovered functions rely on folding to a specific conformation or transitioning between conformations. The RNA structure contains rigid, short basepaired regions connected by more flexible linkers. Studies of model constructs such as small helix-junction-helix (HJH) motifs are useful in understanding how these elements work together to determine RNA conformation. Here, we reveal the full ensemble of solution structures assumed by a model RNA HJH. We apply small-angle x-ray scattering and an ensemble optimization method to selectively refine models generated by all-atom molecular dynamics simulations. The expectation of a broad distribution of helix orientations, at and above physiological ionic strength, is not met. Instead, this analysis shows that the HJH structures are dominated by two distinct conformations at moderate to high ionic strength. Atomic structures, selected from the molecular dynamics simulations, reveal strong base-base interactions in the junction that critically constrain the conformational space available to the HJH molecule and lead to a surprising re-extension at high salt. These results are corroborated by comparison with previous single-molecule fluorescence resonance energy transfer experiments on the same constructs.
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Affiliation(s)
- Yen-Lin Chen
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York
| | - Tongsik Lee
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas
| | - Ron Elber
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas; Institute of Computational Sciences and Engineering, University of Texas at Austin, Austin, Texas
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York.
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24
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Powers KT, Lavering ED, Washington MT. Conformational Flexibility of Ubiquitin-Modified and SUMO-Modified PCNA Shown by Full-Ensemble Hybrid Methods. J Mol Biol 2018; 430:5294-5303. [PMID: 30381149 DOI: 10.1016/j.jmb.2018.10.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/10/2018] [Accepted: 10/23/2018] [Indexed: 01/22/2023]
Abstract
Ubiquitin-modified proliferating cell nuclear antigen (PCNA) and small ubiquitin-like modifier (SUMO)-modified PCNA regulate DNA damage tolerance pathways. X-ray crystal structures of these proteins suggested that they do not have much conformational flexibility because the modifiers have preferred binding sites on the surface of PCNA. By contrast, small-angle X-ray scattering analyses of these proteins suggested that they have different degrees of conformational flexibility, with SUMO-modified PCNA being more flexible. These conclusions were based on minimal-ensemble hybrid approaches, which produce unrealistic models by representing flexible proteins with only a few static structures. To overcome the limitations of minimal-ensemble hybrid approaches and to determine the degree of conformational flexibility of ubiquitin-modified PCNA and SUMO-modified PCNA, we utilized a novel full-ensemble hybrid approach. We carried out molecular simulations and small-angle X-ray scattering analyses of both proteins and obtained outstanding agreement between the full ensembles generated by the simulations and the experimental data. We found that both proteins have a high degree of conformational flexibility. The modifiers occupy many positions around the back and side of the PCNA ring. Moreover, we found no preferred ubiquitin-binding or SUMO-binding sites on PCNA. This conformational flexibility likely facilitates the recognition of downstream effector proteins and the formation of PCNA tool belts.
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Affiliation(s)
- Kyle T Powers
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242-1109, USA
| | - Emily D Lavering
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242-1109, USA
| | - M Todd Washington
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242-1109, USA.
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25
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Zettl T, Mathew RS, Shi X, Doniach S, Herschlag D, Harbury PAB, Lipfert J. Gold nanocrystal labels provide a sequence-to-3D structure map in SAXS reconstructions. SCIENCE ADVANCES 2018; 4:eaar4418. [PMID: 29806025 PMCID: PMC5969820 DOI: 10.1126/sciadv.aar4418] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 04/17/2018] [Indexed: 06/08/2023]
Abstract
Small-angle x-ray scattering (SAXS) is a powerful technique to probe the structure of biological macromolecules and their complexes under virtually arbitrary solution conditions, without the need for crystallization. While it is possible to reconstruct molecular shapes from SAXS data ab initio, the resulting electron density maps have a resolution of ~1 nm and are often insufficient to reliably assign secondary structure elements or domains. We show that SAXS data of gold-labeled samples significantly enhance the information content of SAXS measurements, allowing the unambiguous assignment of macromolecular sequence motifs to specific locations within a SAXS structure. We first demonstrate our approach for site-specifically internally and end-labeled DNA and an RNA motif. In addition, we present a protocol for highly uniform and site-specific labeling of proteins with small (~1.4 nm diameter) gold particles and apply our method to the signaling protein calmodulin. In all cases, the position of the small gold probes can be reliably identified in low-resolution electron density maps. Enhancing low-resolution measurements by site-selective gold labeling provides an attractive approach to aid modeling of a large range of macromolecular systems.
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Affiliation(s)
- Thomas Zettl
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, LMU Munich, Munich, Germany
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
| | - Rebecca S. Mathew
- Department of Cell Biology, Harvard Medical School, Harvard University, Boston, MA 02115, USA
| | - Xuesong Shi
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
| | - Sebastian Doniach
- Departments of Applied Physics and Physics, Stanford University, Stanford, CA 94305, USA
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Pehr A. B. Harbury
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
| | - Jan Lipfert
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, LMU Munich, Munich, Germany
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26
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Joo K, Heo S, Joung I, Hong SH, Lee SJ, Lee J. Data-assisted protein structure modeling by global optimization in CASP12. Proteins 2018; 86 Suppl 1:240-246. [PMID: 29341255 DOI: 10.1002/prot.25457] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 12/29/2017] [Accepted: 01/08/2018] [Indexed: 12/26/2022]
Abstract
In CASP12, 2 types of data-assisted protein structure modeling were experimented. Either SAXS experimental data or cross-linking experimental data was provided for a selected number of CASP12 targets that the CASP12 predictor could utilize for better protein structure modeling. We devised 2 separate energy terms for SAXS data and cross-linking data to drive the model structures into more native-like structures that satisfied the given experimental data as much as possible. In CASP11, we successfully performed protein structure modeling using simulated sparse and ambiguously assigned NOE data and/or correct residue-residue contact information, where the only energy term that folded the protein into its native structure was the term which was originated from the given experimental data. However, the 2 types of experimental data provided in CASP12 were far from being sufficient enough to fold the target protein into its native structure because SAXS data provides only the overall shape of the molecule and the cross-linking contact information provides only very low-resolution distance information. For this reason, we combined the SAXS or cross-linking energy term with our regular modeling energy function that includes both the template energy term and the de novo energy terms. By optimizing the newly formulated energy function, we obtained protein models that fit better with provided SAXS data than the X-ray structure of the target. However, the improvement of the model relative to the 1 modeled without the SAXS data, was not significant. Consistent structural improvement was achieved by incorporating cross-linking data into the protein structure modeling.
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Affiliation(s)
- Keehyoung Joo
- Center for In Silico Protein Science, Korea Institute for Advanced Study, Seoul, 02455, South Korea.,Center for Advanced Computation, Korea Institute for Advanced Study, Seoul, 02455, South Korea
| | - Seungryong Heo
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, 02455, South Korea
| | - InSuk Joung
- Center for In Silico Protein Science, Korea Institute for Advanced Study, Seoul, 02455, South Korea
| | - Seung Hwan Hong
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, 02455, South Korea
| | - Sung Jong Lee
- Center for In Silico Protein Science, Korea Institute for Advanced Study, Seoul, 02455, South Korea.,The Research Institute for Basic Sciences, Changwon National University, Changwon-Si, Gyeongsangnam-do, South Korea
| | - Jooyoung Lee
- Center for In Silico Protein Science, Korea Institute for Advanced Study, Seoul, 02455, South Korea.,Center for Advanced Computation, Korea Institute for Advanced Study, Seoul, 02455, South Korea.,School of Computational Sciences, Korea Institute for Advanced Study, Seoul, 02455, South Korea
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27
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Nasedkin A, Davidsson J, Niemi AJ, Peng X. Solution x-ray scattering and structure formation in protein dynamics. Phys Rev E 2018; 96:062405. [PMID: 29347365 DOI: 10.1103/physreve.96.062405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Indexed: 11/07/2022]
Abstract
We propose a computationally effective approach that builds on Landau mean-field theory in combination with modern nonequilibrium statistical mechanics to model and interpret protein dynamics and structure formation in small- to wide-angle x-ray scattering (S/WAXS) experiments. We develop the methodology by analyzing experimental data in the case of Engrailed homeodomain protein as an example. We demonstrate how to interpret S/WAXS data qualitatively with a good precision and over an extended temperature range. We explain experimental observations in terms of protein phase structure, and we make predictions for future experiments and for how to analyze data at different ambient temperature values. We conclude that the approach we propose has the potential to become a highly accurate, computationally effective, and predictive tool for analyzing S/WAXS data. For this, we compare our results with those obtained previously in an all-atom molecular dynamics simulation.
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Affiliation(s)
- Alexandr Nasedkin
- Department of Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Jan Davidsson
- Department of Chemistry, Uppsala University, P. O. Box 803, S-75108, Uppsala, Sweden
| | - Antti J Niemi
- Department of Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.,Nordita, Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden.,Department of Physics and Astronomy, Uppsala University, P. O. Box 803, S-75108, Uppsala, Sweden.,Laboratoire de Mathematiques et Physique Theorique CNRS UMR 6083, Fédération Denis Poisson, Université de Tours, Parc de Grandmont, F37200, Tours, France.,School of Physics, Beijing Institute of Technology, Beijing 100081, P.R. China.,Laboratory of Physics of Living Matter, School of Biomedicine, Far Eastern Federal University, Vladivostok 690090, Russia¶
| | - Xubiao Peng
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
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28
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Trewhella J. Small Angle Scattering and Structural Biology: Data Quality and Model Validation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1105:77-100. [PMID: 30617825 DOI: 10.1007/978-981-13-2200-6_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
This chapter provides a brief review of the current state-of-the-art in small-angle scattering (SAS) from biomolecules in solution in regard to: (1) sample preparation and instrumentation, (2) data reduction and analysis, and (3) three-dimensional structural modelling and validation. In this context, areas of ongoing research in regard to the interpretation of SAS data will be discussed with a particular focus on structural modelling using computational methods and data from different experimental techniques, including SAS (hybrid methods). Finally, progress made in establishing community accepted publication guidelines and a standard reporting framework that includes SAS data deposition in a public data bank will be described. Importantly, SAS data with associated meta-data can now be held in a format that supports exchange between data archives and seamless interoperability with the world-wide Protein Data Bank (wwPDB). Biomolecular SAS is thus well positioned to contribute to an envisioned federation of data archives in support of hybrid structural biology.
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Affiliation(s)
- Jill Trewhella
- School of Life and Environmental Sciences, The University of Sydney, NSW, Australia. .,Department of Chemistry, University of Utah, Salt Lake City, UT, USA.
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29
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Rambo RP. Considerations for Sample Preparation Using Size-Exclusion Chromatography for Home and Synchrotron Sources. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1009:31-45. [PMID: 29218552 PMCID: PMC6126186 DOI: 10.1007/978-981-10-6038-0_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The success of a SAXS experiment for structural investigations depends on two precise measurements, the sample and the buffer background. Buffer matching between the sample and background can be achieved using dialysis methods but in biological SAXS of monodisperse systems, sample preparation is routinely being performed with size exclusion chromatography (SEC). SEC is the most reliable method for SAXS sample preparation as the method not only purifies the sample for SAXS but also almost guarantees ideal buffer matching. Here, I will highlight the use of SEC for SAXS sample preparation and demonstrate using example proteins that SEC purification does not always provide for ideal samples. Scrutiny of the SEC elution peak using quasi-elastic and multi-angle light scattering techniques can reveal hidden features (heterogeneity) of the sample that should be considered during SAXS data analysis. In some cases, sample heterogeneity can be controlled using a small molecule additive and I outline a simple additive screening method for sample preparation.
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Affiliation(s)
- Robert P Rambo
- Diamond Light Source Ltd., Harwell Science & Innovation Campus, Didcot, OX11 0DE, UK.
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30
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Brosey CA, Ahmed Z, Lees-Miller SP, Tainer JA. What Combined Measurements From Structures and Imaging Tell Us About DNA Damage Responses. Methods Enzymol 2017; 592:417-455. [PMID: 28668129 DOI: 10.1016/bs.mie.2017.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
DNA damage outcomes depend upon the efficiency and fidelity of DNA damage responses (DDRs) for different cells and damage. As such, DDRs represent tightly regulated prototypical systems for linking nanoscale biomolecular structure and assembly to the biology of genomic regulation and cell signaling. However, the dynamic and multifunctional nature of DDR assemblies can render elusive the correlation between the structures of DDR factors and specific biological disruptions to the DDR when these structures are altered. In this chapter, we discuss concepts and strategies for combining structural, biophysical, and imaging techniques to investigate DDR recognition and regulation, and thus bridge sequence-level structural biochemistry to quantitative biological outcomes visualized in cells. We focus on representative DDR responses from PARP/PARG/AIF damage signaling in DNA single-strand break repair and nonhomologous end joining complexes in double-strand break repair. Methods with exemplary experimental results are considered with a focus on strategies for probing flexibility, conformational changes, and assembly processes that shape a predictive understanding of DDR mechanisms in a cellular context. Integration of structural and imaging measurements promises to provide foundational knowledge to rationally control and optimize DNA damage outcomes for synthetic lethality and for immune activation with resulting insights for biology and cancer interventions.
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Affiliation(s)
- Chris A Brosey
- The University of Texas, M.D. Anderson Cancer Center, Houston, TX, United States
| | - Zamal Ahmed
- The University of Texas, M.D. Anderson Cancer Center, Houston, TX, United States
| | - Susan P Lees-Miller
- Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, AB, Canada.
| | - John A Tainer
- The University of Texas, M.D. Anderson Cancer Center, Houston, TX, United States; Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.
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31
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Designing and Performing Biological Solution Small-Angle Neutron Scattering Contrast Variation Experiments on Multi-component Assemblies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1009:65-85. [DOI: 10.1007/978-981-10-6038-0_5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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32
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Abstract
AbstractIn 1912, Max von Laue and collaborators first observed diffraction spots from a millimeter-sized crystal of copper sulfate using an X-ray tube. Crystallography was born of this experiment, and since then, diffraction by both X-rays and electrons has revealed a myriad of inorganic and organic structures, including structures of complex protein assemblies. Advancements in X-ray sources have spurred a revolution in structure determination, facilitated by the development of new methods. This review explores some of the frontier methods that are shaping the future of X-ray diffraction, including coherent diffractive imaging, serial femtosecond X-ray crystallography and small-angle X-ray scattering. Collectively, these methods expand the current limits of structure determination in biological systems across multiple length and time scales.
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33
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Arentson BW, Hayes EL, Zhu W, Singh H, Tanner JJ, Becker DF. Engineering a trifunctional proline utilization A chimaera by fusing a DNA-binding domain to a bifunctional PutA. Biosci Rep 2016; 36:e00413. [PMID: 27742866 PMCID: PMC5293562 DOI: 10.1042/bsr20160435] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 10/05/2016] [Accepted: 10/14/2016] [Indexed: 01/18/2023] Open
Abstract
Proline utilization A (PutA) is a bifunctional flavoenzyme with proline dehydrogenase (PRODH) and Δ1-pyrroline-5-carboxylate (P5C) dehydrogenase (P5CDH) domains that catalyses the two-step oxidation of proline to glutamate. Trifunctional PutAs also have an N-terminal ribbon-helix-helix (RHH) DNA-binding domain and moonlight as autogenous transcriptional repressors of the put regulon. A unique property of trifunctional PutA is the ability to switch functions from DNA-bound repressor to membrane-associated enzyme in response to cellular nutritional needs and proline availability. In the present study, we attempt to construct a trifunctional PutA by fusing the RHH domain of Escherichia coli PutA (EcRHH) to the bifunctional Rhodobacter capsulatus PutA (RcPutA) in order to explore the modular design of functional switching in trifunctional PutAs. The EcRHH-RcPutA chimaera retains the catalytic properties of RcPutA while acquiring the oligomeric state, quaternary structure and DNA-binding properties of EcPutA. Furthermore, the EcRHH-RcPutA chimaera exhibits proline-induced lipid association, which is a fundamental characteristic of functional switching. Unexpectedly, RcPutA lipid binding is also activated by proline, which shows for the first time that bifunctional PutAs exhibit a limited form of functional switching. Altogether, these results suggest that the C-terminal domain (CTD), which is conserved by trifunctional PutAs and certain bifunctional PutAs, is essential for functional switching in trifunctional PutAs.
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Affiliation(s)
- Benjamin W Arentson
- Department of Biochemistry, Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68588, U.S.A
| | - Erin L Hayes
- Department of Biochemistry, Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68588, U.S.A
| | - Weidong Zhu
- Department of Biochemistry, Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68588, U.S.A
| | - Harkewal Singh
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211, U.S.A
- Protein Technologies and Assays, Research and Development, MilliporeSigma, 2909 Laclede Avenue, St. Louis, MO 63103, U.S.A
| | - John J Tanner
- Department of Biochemistry, University of Missouri-Columbia, Columbia, MO 65211, U.S.A
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211, U.S.A
| | - Donald F Becker
- Department of Biochemistry, Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68588, U.S.A.
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34
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Jeffries CM, Graewert MA, Blanchet CE, Langley DB, Whitten AE, Svergun DI. Preparing monodisperse macromolecular samples for successful biological small-angle X-ray and neutron-scattering experiments. Nat Protoc 2016; 11:2122-2153. [PMID: 27711050 PMCID: PMC5402874 DOI: 10.1038/nprot.2016.113] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) are techniques used to extract structural parameters and determine the overall structures and shapes of biological macromolecules, complexes and assemblies in solution. The scattering intensities measured from a sample contain contributions from all atoms within the illuminated sample volume, including the solvent and buffer components, as well as the macromolecules of interest. To obtain structural information, it is essential to prepare an exactly matched solvent blank so that background scattering contributions can be accurately subtracted from the sample scattering to obtain the net scattering from the macromolecules in the sample. In addition, sample heterogeneity caused by contaminants, aggregates, mismatched solvents, radiation damage or other factors can severely influence and complicate data analysis, so it is essential that the samples be pure and monodisperse for the duration of the experiment. This protocol outlines the basic physics of SAXS and SANS, and it reveals how the underlying conceptual principles of the techniques ultimately 'translate' into practical laboratory guidance for the production of samples of sufficiently high quality for scattering experiments. The procedure describes how to prepare and characterize protein and nucleic acid samples for both SAXS and SANS using gel electrophoresis, size-exclusion chromatography (SEC) and light scattering. Also included are procedures that are specific to X-rays (in-line SEC-SAXS) and neutrons, specifically preparing samples for contrast matching or variation experiments and deuterium labeling of proteins.
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Affiliation(s)
- Cy M. Jeffries
- European Molecular Biology Laboratory (EMBL) Hamburg Outstation, c/o
DESY. Hamburg, 22603, Germany
| | - Melissa A. Graewert
- European Molecular Biology Laboratory (EMBL) Hamburg Outstation, c/o
DESY. Hamburg, 22603, Germany
| | - Clément E. Blanchet
- European Molecular Biology Laboratory (EMBL) Hamburg Outstation, c/o
DESY. Hamburg, 22603, Germany
| | - David B. Langley
- Victor Chang Cardiac Research and Garvan Institutes, Darlinghurst,
NSW, Australia
| | - Andrew E. Whitten
- Australian Nuclear Science and Technology Organisation, Lucas
Heights, NSW, Australia
| | - Dmitri I Svergun
- European Molecular Biology Laboratory (EMBL) Hamburg Outstation, c/o
DESY. Hamburg, 22603, Germany
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35
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Delaforge E, Milles S, Huang JR, Bouvier D, Jensen MR, Sattler M, Hart DJ, Blackledge M. Investigating the Role of Large-Scale Domain Dynamics in Protein-Protein Interactions. Front Mol Biosci 2016; 3:54. [PMID: 27679800 PMCID: PMC5020063 DOI: 10.3389/fmolb.2016.00054] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 08/30/2016] [Indexed: 12/21/2022] Open
Abstract
Intrinsically disordered linkers provide multi-domain proteins with degrees of conformational freedom that are often essential for function. These highly dynamic assemblies represent a significant fraction of all proteomes, and deciphering the physical basis of their interactions represents a considerable challenge. Here we describe the difficulties associated with mapping the large-scale domain dynamics and describe two recent examples where solution state methods, in particular NMR spectroscopy, are used to investigate conformational exchange on very different timescales.
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Affiliation(s)
- Elise Delaforge
- Institut de Biologie Structurale, CEA, Centre National de la Recherche Scientifique, University Grenoble Alpes Grenoble, France
| | - Sigrid Milles
- Institut de Biologie Structurale, CEA, Centre National de la Recherche Scientifique, University Grenoble Alpes Grenoble, France
| | - Jie-Rong Huang
- Institut de Biologie Structurale, CEA, Centre National de la Recherche Scientifique, University Grenoble Alpes Grenoble, France
| | - Denis Bouvier
- Institut de Biologie Structurale, CEA, Centre National de la Recherche Scientifique, University Grenoble Alpes Grenoble, France
| | - Malene Ringkjøbing Jensen
- Institut de Biologie Structurale, CEA, Centre National de la Recherche Scientifique, University Grenoble Alpes Grenoble, France
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Zentrum MünchenNeuherberg, Germany; Center for Integrated Protein Science Munich at Biomolecular NMR, Technische Universität MünchenGarching, Germany
| | - Darren J Hart
- Institut de Biologie Structurale, CEA, Centre National de la Recherche Scientifique, University Grenoble Alpes Grenoble, France
| | - Martin Blackledge
- Institut de Biologie Structurale, CEA, Centre National de la Recherche Scientifique, University Grenoble Alpes Grenoble, France
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36
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Palamini M, Canciani A, Forneris F. Identifying and Visualizing Macromolecular Flexibility in Structural Biology. Front Mol Biosci 2016; 3:47. [PMID: 27668215 PMCID: PMC5016524 DOI: 10.3389/fmolb.2016.00047] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/22/2016] [Indexed: 12/29/2022] Open
Abstract
Structural biology comprises a variety of tools to obtain atomic resolution data for the investigation of macromolecules. Conventional structural methodologies including crystallography, NMR and electron microscopy often do not provide sufficient details concerning flexibility and dynamics, even though these aspects are critical for the physiological functions of the systems under investigation. However, the increasing complexity of the molecules studied by structural biology (including large macromolecular assemblies, integral membrane proteins, intrinsically disordered systems, and folding intermediates) continuously demands in-depth analyses of the roles of flexibility and conformational specificity involved in interactions with ligands and inhibitors. The intrinsic difficulties in capturing often subtle but critical molecular motions in biological systems have restrained the investigation of flexible molecules into a small niche of structural biology. Introduction of massive technological developments over the recent years, which include time-resolved studies, solution X-ray scattering, and new detectors for cryo-electron microscopy, have pushed the limits of structural investigation of flexible systems far beyond traditional approaches of NMR analysis. By integrating these modern methods with powerful biophysical and computational approaches such as generation of ensembles of molecular models and selective particle picking in electron microscopy, more feasible investigations of dynamic systems are now possible. Using some prominent examples from recent literature, we review how current structural biology methods can contribute useful data to accurately visualize flexibility in macromolecular structures and understand its important roles in regulation of biological processes.
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Affiliation(s)
| | | | - Federico Forneris
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of PaviaPavia, Italy
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37
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Marchi M. A first principle particle mesh method for solution SAXS of large bio-molecular systems. J Chem Phys 2016; 145:045101. [DOI: 10.1063/1.4959123] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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38
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A Structure-free Method for Quantifying Conformational Flexibility in proteins. Sci Rep 2016; 6:29040. [PMID: 27358108 PMCID: PMC4928179 DOI: 10.1038/srep29040] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 06/08/2016] [Indexed: 11/24/2022] Open
Abstract
All proteins sample a range of conformations at physiologic temperatures and this inherent flexibility enables them to carry out their prescribed functions. A comprehensive understanding of protein function therefore entails a characterization of protein flexibility. Here we describe a novel approach for quantifying a protein’s flexibility in solution using small-angle X-ray scattering (SAXS) data. The method calculates an effective entropy that quantifies the diversity of radii of gyration that a protein can adopt in solution and does not require the explicit generation of structural ensembles to garner insights into protein flexibility. Application of this structure-free approach to over 200 experimental datasets demonstrates that the methodology can quantify a protein’s disorder as well as the effects of ligand binding on protein flexibility. Such quantitative descriptions of protein flexibility form the basis of a rigorous taxonomy for the description and classification of protein structure.
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39
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Wright GSA, Antonyuk SV, Hasnain SS. A faulty interaction between SOD1 and hCCS in neurodegenerative disease. Sci Rep 2016; 6:27691. [PMID: 27282955 PMCID: PMC4901319 DOI: 10.1038/srep27691] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 05/19/2016] [Indexed: 01/12/2023] Open
Abstract
A proportion of Amyotrophic lateral sclerosis (ALS) cases result from impaired mutant superoxide dismutase-1 (SOD1) maturation. The copper chaperone for SOD1 (hCCS) forms a transient complex with SOD1 and catalyses the final stages of its maturation. We find that a neurodegenerative disease-associated hCCS mutation abrogates the interaction with SOD1 by inhibiting hCCS zinc binding. Analogously, SOD1 zinc loss has a detrimental effect on the formation, structure and disassociation of the hCCS-SOD1 heterodimer. This suggests that hCCS functionality is impaired by ALS mutations that reduce SOD1 zinc affinity. Furthermore, stabilization of wild-type SOD1 by chemical modification including cisplatination, inhibits complex formation. We hypothesize that drug molecules designed to stabilize ALS SOD1 mutants that also target the wild-type form will lead to characteristics common in SOD1 knock-outs. Our work demonstrates the applicability of chromatographic SAXS when studying biomolecules predisposed to aggregation or dissociation; attributes frequently reported for complexes involved in neurodegenerative disease.
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Affiliation(s)
- Gareth S. A. Wright
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
| | - Svetlana V. Antonyuk
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
| | - S. Samar Hasnain
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
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40
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Borges JC, Seraphim TV, Dores-Silva PR, Barbosa LRS. A review of multi-domain and flexible molecular chaperones studies by small-angle X-ray scattering. Biophys Rev 2016; 8:107-120. [PMID: 28510050 PMCID: PMC5425780 DOI: 10.1007/s12551-016-0194-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/02/2016] [Indexed: 02/06/2023] Open
Abstract
Intrinsic flexibility is closely related to protein function, and a plethora of important regulatory proteins have been found to be flexible, multi-domain or even intrinsically disordered. On the one hand, understanding such systems depends on how these proteins behave in solution. On the other, small-angle X-ray scattering (SAXS) is a technique that fulfills the requirements to study protein structure and dynamics relatively quickly with few experimental limitations. Molecular chaperones from Hsp70 and Hsp90 families are multi-domain proteins containing flexible and/or disordered regions that play central roles in cellular proteostasis. Here, we review the structure and function of these proteins by SAXS. Our general approach includes the use of SAXS data to determine size and shape parameters, as well as protein shape reconstruction and their validation by using accessory biophysical tools. Some remarkable examples are presented that exemplify the potential of the SAXS technique. Protein structure can be determined in solution even at limiting protein concentrations (for example, human mortalin, a mitochondrial Hsp70 chaperone). The protein organization, flexibility and function (for example, the J-protein co-chaperones), oligomeric status, domain organization, and flexibility (for the Hsp90 chaperone and the Hip and Hep1 co-chaperones) may also be determined. Lastly, the shape, structural conservation, and protein dynamics (for the Hsp90 chaperone and both p23 and Aha1 co-chaperones) may be studied by SAXS. We believe this review will enhance the application of the SAXS technique to the study of the molecular chaperones.
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Affiliation(s)
- Júlio C Borges
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.
| | - Thiago V Seraphim
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
| | - Paulo R Dores-Silva
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
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41
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Cao H, Tan K, Wang F, Bigelow L, Yennamalli RM, Jedrzejczak R, Babnigg G, Bingman CA, Joachimiak A, Kharel MK, Singh S, Thorson JS, Phillips GN. Structural dynamics of a methionine γ-lyase for calicheamicin biosynthesis: Rotation of the conserved tyrosine stacking with pyridoxal phosphate. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2016; 3:034702. [PMID: 27191010 PMCID: PMC4851618 DOI: 10.1063/1.4948539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 04/21/2016] [Indexed: 06/05/2023]
Abstract
CalE6 from Micromonospora echinospora is a (pyridoxal 5' phosphate) PLP-dependent methionine γ-lyase involved in the biosynthesis of calicheamicins. We report the crystal structure of a CalE6 2-(N-morpholino)ethanesulfonic acid complex showing ligand-induced rotation of Tyr100, which stacks with PLP, resembling the corresponding tyrosine rotation of true catalytic intermediates of CalE6 homologs. Elastic network modeling and crystallographic ensemble refinement reveal mobility of the N-terminal loop, which involves both tetrameric assembly and PLP binding. Modeling and comparative structural analysis of PLP-dependent enzymes involved in Cys/Met metabolism shine light on the functional implications of the intrinsic dynamic properties of CalE6 in catalysis and holoenzyme maturation.
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Affiliation(s)
- Hongnan Cao
- Biosciences at Rice, Rice University , 6100 Main St., Houston, Texas 77005, USA
| | - Kemin Tan
- Biosciences Division, Midwest Center for Structural Genomics, Argonne National Laboratory , Bldg. 446/Rm. A104, 970 South Cass Avenue, Argonne, Illinois 60439, USA
| | - Fengbin Wang
- Biosciences at Rice, Rice University , 6100 Main St., Houston, Texas 77005, USA
| | - Lance Bigelow
- Biosciences Division, Midwest Center for Structural Genomics, Argonne National Laboratory , Bldg. 446/Rm. A104, 970 South Cass Avenue, Argonne, Illinois 60439, USA
| | | | - Robert Jedrzejczak
- Biosciences Division, Midwest Center for Structural Genomics, Argonne National Laboratory , Bldg. 446/Rm. A104, 970 South Cass Avenue, Argonne, Illinois 60439, USA
| | - Gyorgy Babnigg
- Biosciences Division, Midwest Center for Structural Genomics, Argonne National Laboratory , Bldg. 446/Rm. A104, 970 South Cass Avenue, Argonne, Illinois 60439, USA
| | - Craig A Bingman
- Department of Biochemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, USA
| | - Andrzej Joachimiak
- Biosciences Division, Midwest Center for Structural Genomics, Argonne National Laboratory , Bldg. 446/Rm. A104, 970 South Cass Avenue, Argonne, Illinois 60439, USA
| | - Madan K Kharel
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky , Lexington, Kentucky 40536, USA
| | - Shanteri Singh
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky , Lexington, Kentucky 40536, USA
| | - Jon S Thorson
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky , Lexington, Kentucky 40536, USA
| | - George N Phillips
- Biosciences at Rice, Rice University , 6100 Main St., Houston, Texas 77005, USA
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42
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Lerche M, Dian C, Round A, Lönneborg R, Brzezinski P, Leonard GA. The solution configurations of inactive and activated DntR have implications for the sliding dimer mechanism of LysR transcription factors. Sci Rep 2016; 6:19988. [PMID: 26817994 PMCID: PMC4730206 DOI: 10.1038/srep19988] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 12/21/2015] [Indexed: 11/09/2022] Open
Abstract
LysR Type Transcriptional Regulators (LTTRs) regulate basic metabolic pathways or virulence gene expression in prokaryotes. Evidence suggests that the activation of LTTRs involves a conformational change from an inactive compact apo- configuration that represses transcription to an active, expanded holo- form that promotes it. However, no LTTR has yet been observed to adopt both configurations. Here, we report the results of structural studies of various forms of the LTTR DntR. Crystal structures of apo-DntR and of a partially autoinducing mutant H169T-DntR suggest that active and inactive DntR maintain a compact homotetrameric configuration. However, Small Angle X-ray Scattering (SAXS) studies on solutions of apo-, H169T- and inducer-bound holo-DntR indicate a different behaviour, suggesting that while apo-DntR maintains a compact configuration in solution both H169T- and holo-DntR adopt an expanded conformation. Models of the SAXS-obtained solution conformations of apo- and holo-DntR homotetramers in complex with promoter-operator region DNA are consistent with previous observations of a shifting of LTTR DNA binding sites upon activation and a consequent relaxation in the bend of the promoter-operator region DNA. Our results thus provide clear evidence at the molecular level which strongly supports the 'sliding dimer' hypothesis concerning LTTR activation mechanisms.
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Affiliation(s)
- Michael Lerche
- Structural Bioloy Group, European Synchrotron Radiation Facility
(ESRF), CS 40220, 38043
Grenoble Cedex 9, France
| | - Cyril Dian
- Institut de Biologie Structurale Jean-Pierre Ebel,
71 avenue des Martyrs, CS 10090, 38044
Grenoble Cedex 9, France
| | - Adam Round
- European Molecular Biology Laboratory, Grenoble
Outstation, 38042
Grenoble Cedex 9, France
- Unit for Virus Host-Cell Interactions, University Grenoble
Alpes-EMBL-CNRS, 38042
Grenoble Cedex 9, France
| | - Rosa Lönneborg
- Department of Biochemistry and Biophysics, Arrhenius
Laboratories for Natural Sciences, Stockholm University, SE-106
91
Stockholm, Sweden
| | - Peter Brzezinski
- Department of Biochemistry and Biophysics, Arrhenius
Laboratories for Natural Sciences, Stockholm University, SE-106
91
Stockholm, Sweden
| | - Gordon A. Leonard
- Structural Bioloy Group, European Synchrotron Radiation Facility
(ESRF), CS 40220, 38043
Grenoble Cedex 9, France
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43
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Gaullier G, Miron S, Pisano S, Buisson R, Le Bihan YV, Tellier-Lebègue C, Messaoud W, Roblin P, Guimarães BG, Thai R, Giraud-Panis MJ, Gilson E, Le Du MH. A higher-order entity formed by the flexible assembly of RAP1 with TRF2. Nucleic Acids Res 2016; 44:1962-76. [PMID: 26748096 PMCID: PMC4770236 DOI: 10.1093/nar/gkv1531] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/21/2015] [Indexed: 11/13/2022] Open
Abstract
Telomere integrity is essential to maintain genome stability, and telomeric dysfunctions are associated with cancer and aging pathologies. In human, the shelterin complex binds TTAGGG DNA repeats and provides capping to chromosome ends. Within shelterin, RAP1 is recruited through its interaction with TRF2, and TRF2 is required for telomere protection through a network of nucleic acid and protein interactions. RAP1 is one of the most conserved shelterin proteins although one unresolved question is how its interaction may influence TRF2 properties and regulate its capacity to bind multiple proteins. Through a combination of biochemical, biophysical and structural approaches, we unveiled a unique mode of assembly between RAP1 and TRF2. The complete interaction scheme between the full-length proteins involves a complex biphasic interaction of RAP1 that directly affects the binding properties of the assembly. These results reveal how a non-DNA binding protein can influence the properties of a DNA-binding partner by mutual conformational adjustments.
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Affiliation(s)
- Guillaume Gaullier
- Department of Biochemistry, Biophysics and Structural Biology, Institute for Integrative Biology of the Cell (I2BC), CEA, UMR 9198 CNRS, Université Paris-Sud, Batiment 144, CEA Saclay, Gif-sur-Yvette, F-91191, France
| | - Simona Miron
- Department of Biochemistry, Biophysics and Structural Biology, Institute for Integrative Biology of the Cell (I2BC), CEA, UMR 9198 CNRS, Université Paris-Sud, Batiment 144, CEA Saclay, Gif-sur-Yvette, F-91191, France
| | - Sabrina Pisano
- Institute for Research on Cancer and Aging, Nice (IRCAN); CNRS UMR7284/INSERM U1081; Faculty of Medicine; Nice, 06107, France
| | - Rémi Buisson
- Institute for Research on Cancer and Aging, Nice (IRCAN); CNRS UMR7284/INSERM U1081; Faculty of Medicine; Nice, 06107, France
| | - Yann-Vaï Le Bihan
- Department of Biochemistry, Biophysics and Structural Biology, Institute for Integrative Biology of the Cell (I2BC), CEA, UMR 9198 CNRS, Université Paris-Sud, Batiment 144, CEA Saclay, Gif-sur-Yvette, F-91191, France
| | - Carine Tellier-Lebègue
- Department of Biochemistry, Biophysics and Structural Biology, Institute for Integrative Biology of the Cell (I2BC), CEA, UMR 9198 CNRS, Université Paris-Sud, Batiment 144, CEA Saclay, Gif-sur-Yvette, F-91191, France
| | - Wala Messaoud
- Department of Biochemistry, Biophysics and Structural Biology, Institute for Integrative Biology of the Cell (I2BC), CEA, UMR 9198 CNRS, Université Paris-Sud, Batiment 144, CEA Saclay, Gif-sur-Yvette, F-91191, France
| | - Pierre Roblin
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin BP 48, 91192 GIF-SUR-YVETTE Cedex, France Institut National de la Recherche Agronomique, Unité Biopolymères, Interactions, Assemblages, 44316 Nantes, France
| | - Beatriz G Guimarães
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin BP 48, 91192 GIF-SUR-YVETTE Cedex, France
| | - Robert Thai
- CEA, iBiTecS, F-91191 Gif-sur-Yvette, France
| | - Marie-Josèphe Giraud-Panis
- Institute for Research on Cancer and Aging, Nice (IRCAN); CNRS UMR7284/INSERM U1081; Faculty of Medicine; Nice, 06107, France
| | - Eric Gilson
- Institute for Research on Cancer and Aging, Nice (IRCAN); CNRS UMR7284/INSERM U1081; Faculty of Medicine; Nice, 06107, France Department of Genetics, CHU; Nice, 06107, France
| | - Marie-Hélène Le Du
- Department of Biochemistry, Biophysics and Structural Biology, Institute for Integrative Biology of the Cell (I2BC), CEA, UMR 9198 CNRS, Université Paris-Sud, Batiment 144, CEA Saclay, Gif-sur-Yvette, F-91191, France
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44
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Zaccai NR, Sandlin CW, Hoopes JT, Curtis JE, Fleming PJ, Fleming KG, Krueger S. Deuterium Labeling Together with Contrast Variation Small-Angle Neutron Scattering Suggests How Skp Captures and Releases Unfolded Outer Membrane Proteins. Methods Enzymol 2015; 566:159-210. [PMID: 26791979 PMCID: PMC4913355 DOI: 10.1016/bs.mie.2015.06.041] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In Gram-negative bacteria, the chaperone protein Skp forms specific and stable complexes with membrane proteins while they are transported across the periplasm to the outer membrane. The jellyfish-like architecture of Skp is similar to the eukaryotic and archaeal prefoldins and the mitochondrial Tim chaperones, that is the α-helical "tentacles" extend from a β-strand "body" to create an internal cavity. Contrast variation small-angle neutron scattering (SANS) experiments on Skp alone in solution and bound in two different complexes to unfolded outer membrane proteins (uOMPs), OmpA and OmpW, demonstrate that the helical tentacles of Skp bind their substrate in a clamp-like mechanism in a conformation similar to that previously observed in the apo crystal structure of Skp. Deuteration of the uOMP component combined with contrast variation analysis allowed the shapes of Skp and uOMP as well as the location of uOMP with respect to Skp to be determined in both complexes. This represents unique information that could not be obtained without deuterium labeling of the uOMPs. The data yield the first direct structural evidence that the α-helical Skp tentacles move closer together on binding its substrate and that the structure of Skp is different when binding different uOMPs. This work presents, by example, a tutorial on performing SANS experiments using both deuterium labeling and contrast variation, including SANS theory, sample preparation, data collection, sample quality validation, data analysis, and structure modeling.
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Affiliation(s)
- Nathan R Zaccai
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Clifford W Sandlin
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - James T Hoopes
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland, USA
| | - Joseph E Curtis
- National Institute of Standards and Technology, Gaithersburg, Maryland, USA
| | - Patrick J Fleming
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Karen G Fleming
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Susan Krueger
- National Institute of Standards and Technology, Gaithersburg, Maryland, USA.
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45
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Curry S. Structural Biology: A Century-long Journey into an Unseen World. INTERDISCIPLINARY SCIENCE REVIEWS : ISR 2015; 40:308-328. [PMID: 26740732 PMCID: PMC4697198 DOI: 10.1179/0308018815z.000000000120] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
When the first atomic structures of salt crystals were determined by the Braggs in 1912-1913, the analytical power of X-ray crystallography was immediately evident. Within a few decades the technique was being applied to the more complex molecules of chemistry and biology and is rightly regarded as the foundation stone of structural biology, a field that emerged in the 1950s when X-ray diffraction analysis revealed the atomic architecture of DNA and protein molecules. Since then the toolbox of structural biology has been augmented by other physical techniques, including nuclear magnetic resonance spectroscopy, electron microscopy, and solution scattering of X-rays and neutrons. Together these have transformed our understanding of the molecular basis of life. Here I review the major and most recent developments in structural biology that have brought us to the threshold of a landscape of astonishing molecular complexity.
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Affiliation(s)
- Stephen Curry
- Department of Life Sciences, Imperial College London, UK
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46
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Kimanius D, Pettersson I, Schluckebier G, Lindahl E, Andersson M. SAXS-Guided Metadynamics. J Chem Theory Comput 2015; 11:3491-8. [DOI: 10.1021/acs.jctc.5b00299] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Dari Kimanius
- Department
of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ingrid Pettersson
- Modeling
and Structural Biology, Protein Engineering, Global Research, Novo Nordisk A/S, Novo
Nordisk Park, DK-2760 Måløv, Denmark
| | - Gerd Schluckebier
- Modeling
and Structural Biology, Protein Engineering, Global Research, Novo Nordisk A/S, Novo
Nordisk Park, DK-2760 Måløv, Denmark
| | - Erik Lindahl
- Department
of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, SE-106 91 Stockholm, Sweden
- Department
of Theoretical Physics and Swedish e-Science Research Center, Science
for Life Laboratory, KTH Royal Institute of Technology, SE-171 21 Solna, Sweden
| | - Magnus Andersson
- Department
of Theoretical Physics and Swedish e-Science Research Center, Science
for Life Laboratory, KTH Royal Institute of Technology, SE-171 21 Solna, Sweden
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47
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Fuss JO, Tsai CL, Ishida JP, Tainer JA. Emerging critical roles of Fe-S clusters in DNA replication and repair. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1853:1253-71. [PMID: 25655665 PMCID: PMC4576882 DOI: 10.1016/j.bbamcr.2015.01.018] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 01/13/2015] [Accepted: 01/26/2015] [Indexed: 10/24/2022]
Abstract
Fe-S clusters are partners in the origin of life that predate cells, acetyl-CoA metabolism, DNA, and the RNA world. The double helix solved the mystery of DNA replication by base pairing for accurate copying. Yet, for genome stability necessary to life, the double helix has equally important implications for damage repair. Here we examine striking advances that uncover Fe-S cluster roles both in copying the genetic sequence by DNA polymerases and in crucial repair processes for genome maintenance, as mutational defects cause cancer and degenerative disease. Moreover, we examine an exciting, controversial role for Fe-S clusters in a third element required for life - the long-range coordination and regulation of replication and repair events. By their ability to delocalize electrons over both Fe and S centers, Fe-S clusters have unbeatable features for protein conformational control and charge transfer via double-stranded DNA that may fundamentally transform our understanding of life, replication, and repair. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- Jill O Fuss
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
| | - Chi-Lin Tsai
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Justin P Ishida
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - John A Tainer
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA; Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA.
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48
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Wen B, Peng J, Zuo X, Gong Q, Zhang Z. Characterization of protein flexibility using small-angle x-ray scattering and amplified collective motion simulations. Biophys J 2015; 107:956-64. [PMID: 25140431 DOI: 10.1016/j.bpj.2014.07.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 06/08/2014] [Accepted: 07/01/2014] [Indexed: 01/12/2023] Open
Abstract
Large-scale flexibility within a multidomain protein often plays an important role in its biological function. Despite its inherent low resolution, small-angle x-ray scattering (SAXS) is well suited to investigate protein flexibility and determine, with the help of computational modeling, what kinds of protein conformations would coexist in solution. In this article, we develop a tool that combines SAXS data with a previously developed sampling technique called amplified collective motions (ACM) to elucidate structures of highly dynamic multidomain proteins in solution. We demonstrate the use of this tool in two proteins, bacteriophage T4 lysozyme and tandem WW domains of the formin-binding protein 21. The ACM simulations can sample the conformational space of proteins much more extensively than standard molecular dynamics (MD) simulations. Therefore, conformations generated by ACM are significantly better at reproducing the SAXS data than are those from MD simulations.
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Affiliation(s)
- Bin Wen
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - Junhui Peng
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - Xiaobing Zuo
- Advanced Photon Source, Argonne National Laboratory, Chicago, Illinois
| | - Qingguo Gong
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - Zhiyong Zhang
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, People's Republic of China.
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49
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Tsutakawa SE, Yan C, Xu X, Weinacht CP, Freudenthal BD, Yang K, Zhuang Z, Washington MT, Tainer JA, Ivanov I. Structurally distinct ubiquitin- and sumo-modified PCNA: implications for their distinct roles in the DNA damage response. Structure 2015; 23:724-733. [PMID: 25773143 DOI: 10.1016/j.str.2015.02.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 01/28/2015] [Accepted: 02/09/2015] [Indexed: 11/18/2022]
Abstract
Proliferating cell nuclear antigen (PCNA) is a pivotal replication protein, which also controls cellular responses to DNA damage. Posttranslational modification of PCNA by SUMO and ubiquitin modulate these responses. How the modifiers alter PCNA-dependent DNA repair and damage tolerance pathways is largely unknown. We used hybrid methods to identify atomic models of PCNAK107-Ub and PCNAK164-SUMO consistent with small-angle X-ray scattering data of these complexes in solution. We show that SUMO and ubiquitin have distinct modes of association to PCNA. Ubiquitin adopts discrete docked binding positions. By contrast, SUMO associates by simple tethering and adopts extended flexible conformations. These structural differences are the result of the opposite electrostatic potentials of SUMO and Ub. The unexpected contrast in conformational behavior of Ub-PCNA and SUMO-PCNA has implications for interactions with partner proteins, interacting surfaces accessibility, and access points for pathway regulation.
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Affiliation(s)
- Susan E Tsutakawa
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720 USA
| | - Chunli Yan
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30302 USA
| | - Xiaojun Xu
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30302 USA
| | | | - Bret D Freudenthal
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242 USA
| | - Kun Yang
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716 USA
| | - Zhihao Zhuang
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716 USA
| | - M Todd Washington
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242 USA
| | - John A Tainer
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720 USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, 92037 USA
- Skaggs Institute for Chemical Biology, La Jolla, CA, 92037 USA
| | - Ivaylo Ivanov
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30302 USA
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50
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Lafrance-Vanasse J, Williams GJ, Tainer JA. Envisioning the dynamics and flexibility of Mre11-Rad50-Nbs1 complex to decipher its roles in DNA replication and repair. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 117:182-193. [PMID: 25576492 PMCID: PMC4417436 DOI: 10.1016/j.pbiomolbio.2014.12.004] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 12/20/2014] [Accepted: 12/28/2014] [Indexed: 12/23/2022]
Abstract
The Mre11-Rad50-Nbs1 (MRN) complex is a dynamic macromolecular machine that acts in the first steps of DNA double strand break repair, and each of its components has intrinsic dynamics and flexibility properties that are directly linked with their functions. As a result, deciphering the functional structural biology of the MRN complex is driving novel and integrated technologies to define the dynamic structural biology of protein machinery interacting with DNA. Rad50 promotes dramatic long-range allostery through its coiled-coil and zinc-hook domains. Its ATPase activity drives dynamic transitions between monomeric and dimeric forms that can be modulated with mutants modifying the ATPase rate to control end joining versus resection activities. The biological functions of Mre11's dual endo- and exonuclease activities in repair pathway choice were enigmatic until recently, when they were unveiled by the development of specific nuclease inhibitors. Mre11 dimer flexibility, which may be regulated in cells to control MRN function, suggests new inhibitor design strategies for cancer intervention. Nbs1 has FHA and BRCT domains to bind multiple interaction partners that further regulate MRN. One of them, CtIP, modulates the Mre11 excision activity for homologous recombination repair. Overall, these combined properties suggest novel therapeutic strategies. Furthermore, they collectively help to explain how MRN regulates DNA repair pathway choice with implications for improving the design and analysis of cancer clinical trials that employ DNA damaging agents or target the DNA damage response.
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Affiliation(s)
| | | | - John A Tainer
- Life Science Division, 1 Cyclotron Road, Berkeley, CA 94720, USA; The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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