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Zacco E, Broglia L, Kurihara M, Monti M, Gustincich S, Pastore A, Plath K, Nagakawa S, Cerase A, Sanchez de Groot N, Tartaglia GG. RNA: The Unsuspected Conductor in the Orchestra of Macromolecular Crowding. Chem Rev 2024; 124:4734-4777. [PMID: 38579177 PMCID: PMC11046439 DOI: 10.1021/acs.chemrev.3c00575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 01/12/2024] [Accepted: 01/18/2024] [Indexed: 04/07/2024]
Abstract
This comprehensive Review delves into the chemical principles governing RNA-mediated crowding events, commonly referred to as granules or biological condensates. We explore the pivotal role played by RNA sequence, structure, and chemical modifications in these processes, uncovering their correlation with crowding phenomena under physiological conditions. Additionally, we investigate instances where crowding deviates from its intended function, leading to pathological consequences. By deepening our understanding of the delicate balance that governs molecular crowding driven by RNA and its implications for cellular homeostasis, we aim to shed light on this intriguing area of research. Our exploration extends to the methodologies employed to decipher the composition and structural intricacies of RNA granules, offering a comprehensive overview of the techniques used to characterize them, including relevant computational approaches. Through two detailed examples highlighting the significance of noncoding RNAs, NEAT1 and XIST, in the formation of phase-separated assemblies and their influence on the cellular landscape, we emphasize their crucial role in cellular organization and function. By elucidating the chemical underpinnings of RNA-mediated molecular crowding, investigating the role of modifications, structures, and composition of RNA granules, and exploring both physiological and aberrant phase separation phenomena, this Review provides a multifaceted understanding of the intriguing world of RNA-mediated biological condensates.
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Affiliation(s)
- Elsa Zacco
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Laura Broglia
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Misuzu Kurihara
- RNA
Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Michele Monti
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Stefano Gustincich
- Central
RNA Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Annalisa Pastore
- UK
Dementia Research Institute at the Maurice Wohl Institute of King’s
College London, London SE5 9RT, U.K.
| | - Kathrin Plath
- Department
of Biological Chemistry, David Geffen School
of Medicine at the University of California Los Angeles, Los Angeles, California 90095, United States
| | - Shinichi Nagakawa
- RNA
Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Andrea Cerase
- Blizard
Institute,
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 4NS, U.K.
- Unit
of Cell and developmental Biology, Department of Biology, Università di Pisa, 56123 Pisa, Italy
| | - Natalia Sanchez de Groot
- Unitat
de Bioquímica, Departament de Bioquímica i Biologia
Molecular, Universitat Autònoma de
Barcelona, 08193 Barcelona, Spain
| | - Gian Gaetano Tartaglia
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
- Catalan
Institution for Research and Advanced Studies, ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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2
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Mufundirwa A, Sakurai Y, Arao M, Matsumoto M, Imai H, Iwamoto H. Contrast variation method applied to structural evaluation of catalysts by X-ray small-angle scattering. Sci Rep 2024; 14:2263. [PMID: 38278843 PMCID: PMC10817912 DOI: 10.1038/s41598-024-52671-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/22/2024] [Indexed: 01/28/2024] Open
Abstract
In the process of developing carbon-supported metal catalysts, determining the catalyst particle-size distribution is an essential step, because this parameter is directly related to the catalytic activities. The particle-size distribution is most effectively determined by small-angle X-ray scattering (SAXS). When metal catalysts are supported by high-performance mesoporous carbon materials, however, their mesopores may lead to erroneous particle-size estimation if the sizes of the catalysts and mesopores are comparable. Here we propose a novel approach to particle-size determination by introducing contrast variation-SAXS (CV-SAXS). In CV-SAXS, a multi-component sample is immersed in an inert solvent with a density equal to that of one of the components, thereby rendering that particular component invisible to X-rays. We used a mixture of tetrabromoethane and dimethyl sulfoxide as a contrast-matching solvent for carbon. As a test sample, we prepared a mixture of a small amount of platinum (Pt) catalyst and a bulk of mesoporous carbon, and subjected it to SAXS measurement in the absence and presence of the solvent. In the absence of the solvent, the estimated Pt particle size was affected by the mesopores, but in the presence of the solvent, the Pt particle size was correctly estimated in spite of the low Pt content. The results demonstrate that the CV-SAXS technique is useful for correctly determining the particle-size distribution for low-Pt-content catalysts, for which demands are increasing to reduce the use of expensive Pt.
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Affiliation(s)
- Albert Mufundirwa
- Research Project Division, Japan Synchrotron Radiation Research Institute, SPring-8, Sayo-Cho, Sayo-Gun, Hyogo, 679-5198, Japan
| | - Yoshiharu Sakurai
- Research Project Division, Japan Synchrotron Radiation Research Institute, SPring-8, Sayo-Cho, Sayo-Gun, Hyogo, 679-5198, Japan
| | - Masazumi Arao
- Fuel Cell Cutting-Edge Research Center Technology Research Association, 3147, Shimomukouyama-Cho, Kofu, Yamanashi, 400-1507, Japan
| | - Masashi Matsumoto
- Fuel Cell Cutting-Edge Research Center Technology Research Association, 3147, Shimomukouyama-Cho, Kofu, Yamanashi, 400-1507, Japan
| | - Hideto Imai
- Fuel Cell Cutting-Edge Research Center Technology Research Association, 3147, Shimomukouyama-Cho, Kofu, Yamanashi, 400-1507, Japan
| | - Hiroyuki Iwamoto
- Research Project Division, Japan Synchrotron Radiation Research Institute, SPring-8, Sayo-Cho, Sayo-Gun, Hyogo, 679-5198, Japan.
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3
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Pandit S, Kundu S, Aswal VK. Interaction among bovine serum albumin (BSA) molecules in the presence of anions: a small-angle neutron scattering study. J Biol Phys 2022; 48:237-251. [PMID: 35416637 DOI: 10.1007/s10867-022-09608-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/30/2022] [Indexed: 01/01/2023] Open
Abstract
Protein-protein interaction in solution strongly depends on dissolved ions and solution pH. Interaction among globular protein (bovine serum albumin, BSA), above and below of its isoelectric point (pI ≈ 4.8), is studied in the presence of anions (Cl-, Br-, I-, F-, SO42-) using small-angle neutron scattering (SANS) technique. The SANS study reveals that the short-range attraction among BSA molecules remains nearly unchanged in the presence of anions, whereas the intermediate-range repulsive interaction increases following the Hofmeister series of anions. Although the interaction strength modifies below and above the pI of BSA, it nearly follows the series.
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Affiliation(s)
- Subhankar Pandit
- Soft Nano Laboratory, Physical Sciences Division, Institute of Advanced Study in Science and Technology, Vigyan Path, Paschim Boragaon, Assam, 781035, Garchuk, Guwahati, India
| | - Sarathi Kundu
- Soft Nano Laboratory, Physical Sciences Division, Institute of Advanced Study in Science and Technology, Vigyan Path, Paschim Boragaon, Assam, 781035, Garchuk, Guwahati, India.
| | - Vinod K Aswal
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India
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4
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Nicolás-García M, Perucini-Avendaño M, Jiménez-Martínez C, Perea-Flores MDJ, Gómez-Patiño MB, Arrieta-Báez D, Dávila-Ortiz G. Bean phenolic compound changes during processing: Chemical interactions and identification. J Food Sci 2021; 86:643-655. [PMID: 33586793 DOI: 10.1111/1750-3841.15632] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 09/08/2020] [Accepted: 01/10/2021] [Indexed: 12/18/2022]
Abstract
The common bean (Phaseolus vulgaris L.) represents one of the main crops for human consumption, due to its nutritional and functional qualities. Phenolic compounds have beneficial health effects, and beans are an essential source of these molecules, being found mainly in the seed coat and its color depends on the concentration and type of phenolic compounds present. The bean during storage and processing, such as cooking, germination, extrusion, and fermentation, undergoes physical, chemical, and structural changes that affect the bioavailability of its nutrients; these changes are related to the interactions between phenolic compounds and other components of the food matrix. This review provides information about the identification and quantification of phenolic compounds present in beans and the changes they undergo during processing. It also includes information on the interactions between the phenolic compounds and the components of the bean's cell wall and the analytical methods used to identify the interactions of phenolic compounds with macromolecules.
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Affiliation(s)
- Mayra Nicolás-García
- Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional (IPN), Av. Wilfrido Massieu S/N, Unidad Profesional Adolfo López Mateos, Zacatenco, Delegación Gustavo A. Madero, Ciudad de México, C.P. 07738, México
| | - Madeleine Perucini-Avendaño
- Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional (IPN), Av. Wilfrido Massieu S/N, Unidad Profesional Adolfo López Mateos, Zacatenco, Delegación Gustavo A. Madero, Ciudad de México, C.P. 07738, México
| | - Cristian Jiménez-Martínez
- Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional (IPN), Av. Wilfrido Massieu S/N, Unidad Profesional Adolfo López Mateos, Zacatenco, Delegación Gustavo A. Madero, Ciudad de México, C.P. 07738, México
| | - María de Jesús Perea-Flores
- Centro de Nanociencias y Micro y Nanotecnologías (IPN), Instituto Politécnico Nacional (IPN), Av. Luis Enrique Erro S/N, Unidad Profesional Adolfo López Mateos, Zacatenco, Delegación Gustavo A. Madero, Ciudad de México, C.P. 07738, México
| | - Mayra Beatriz Gómez-Patiño
- Centro de Nanociencias y Micro y Nanotecnologías (IPN), Instituto Politécnico Nacional (IPN), Av. Luis Enrique Erro S/N, Unidad Profesional Adolfo López Mateos, Zacatenco, Delegación Gustavo A. Madero, Ciudad de México, C.P. 07738, México
| | - Daniel Arrieta-Báez
- Centro de Nanociencias y Micro y Nanotecnologías (IPN), Instituto Politécnico Nacional (IPN), Av. Luis Enrique Erro S/N, Unidad Profesional Adolfo López Mateos, Zacatenco, Delegación Gustavo A. Madero, Ciudad de México, C.P. 07738, México
| | - Gloria Dávila-Ortiz
- Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional (IPN), Av. Wilfrido Massieu S/N, Unidad Profesional Adolfo López Mateos, Zacatenco, Delegación Gustavo A. Madero, Ciudad de México, C.P. 07738, México
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5
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Kaur A, Kaur P, Ahuja S. Förster resonance energy transfer (FRET) and applications thereof. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2020; 12:5532-5550. [PMID: 33210685 DOI: 10.1039/d0ay01961e] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
FRET is a nonradiative process of energy transfer that is based on the dipole-dipole interactions between molecules that are fluorescent. Transfer of energy takes place rapidly from a donor molecule to an acceptor molecule in juxtaposition such as 0 to 10 nm without photonic radiation. FRET has occupied a center stage in biotechnology and biological studies. It is used to gain information on conformation changes in single molecules. The pharmaceutical industry has also developed large fluorescence detection systems with very small sample sizes, at the level of single molecules, using fluorescence correlation spectroscopy.
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Affiliation(s)
- Amrita Kaur
- Computer Science and Engineering Department, Thapar Institute of Engineering and Technology, Patiala, 147001, India
| | - Pardeep Kaur
- Department of Biotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib, Punjab 140407, India.
| | - Sahil Ahuja
- Computer Science and Engineering Department, Thapar Institute of Engineering and Technology, Patiala, 147001, India
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6
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Cheu C, Yang L, Nieh MP. Refining internal bilayer structure of bicelles resolved by extended-q small angle X-ray scattering. Chem Phys Lipids 2020; 231:104945. [PMID: 32621811 DOI: 10.1016/j.chemphyslip.2020.104945] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 06/18/2020] [Accepted: 06/26/2020] [Indexed: 11/15/2022]
Abstract
The internal profile across the bilayer reveals important structural information regarding the crystallinity of acyl chains or the positions of encapsulated species. Here, we demonstrate that a simple five-layer-core-shell discoidal model can be employed to best fit the extended-q small angle X-ray scattering (SAXS) data and resolve the bilayer internal structure (with sub-nanometer resolution) of a nanoscale discoidal system comprised of a mixture of long- and short- chain lipids (known as "bicelles"). In contrast to the traditional core-shell discoidal model, the detailed structure in the hydrophobic core such as the methylene and methyl groups can be distinguished via this model. The refined model is validated by the SAXS data of bicelles whose electron scattering length density of the hydrophobic core is adjusted by the addition of a long-chain lipid with a fluorine-end group. The higher resolution of the bilayer internal structure can be employed to advance our understanding of the interaction and conformation of the membrane and associated molecules, such as membrane-associated proteins and locations of entrapped species in the lipid nanoparticles.
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Affiliation(s)
- Catherine Cheu
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269, USA
| | - Lin Yang
- Brookhaven National Laboratory, PO Box 5000, Upton, NY 11973-5000, USA
| | - Mu-Ping Nieh
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269, USA; Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, CT 06269, USA; Department of Biomedical Engineering, University of Connecticut, Storrs, CT 06269, USA.
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7
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Integrative Structural Biology of Protein-RNA Complexes. Structure 2020; 28:6-28. [DOI: 10.1016/j.str.2019.11.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 11/17/2019] [Accepted: 11/27/2019] [Indexed: 12/16/2022]
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8
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Feldman TB, Ivankov OI, Kuklin AI, Murugova TN, Yakovleva MA, Smitienko OA, Kolchugina IB, Round A, Gordeliy VI, Belushkin AV, Ostrovsky MA. Small-angle neutron and X-ray scattering analysis of the supramolecular organization of rhodopsin in photoreceptor membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:183000. [DOI: 10.1016/j.bbamem.2019.05.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 05/24/2019] [Accepted: 05/28/2019] [Indexed: 01/16/2023]
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9
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Gabel F, Engilberge S, Pérez J, Girard E. Medical contrast media as possible tools for SAXS contrast variation. IUCRJ 2019; 6:521-525. [PMID: 31316796 PMCID: PMC6608644 DOI: 10.1107/s2052252519005943] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 04/29/2019] [Indexed: 05/26/2023]
Abstract
Small-angle X-ray scattering (SAXS) is increasingly used to extract structural information from a multitude of soft-matter and biological systems in aqueous solution, including polymers, detergents, lipids, colloids, proteins and RNA/DNA. When SAXS data are recorded at multiple contrasts, i.e. at different electron densities of the solvent, the internal electron-density profile of solubilized molecular systems can be probed. However, contrast-variation SAXS has been limited by the range of electron densities available by conventional agents such as sugars, glycerol and salt, and by the fact that many soft-matter and biological systems are modified in their presence. Here we present a pioneering SAXS contrast-variation study on DDM (n-do-decyl-β-d-malto-pyran-oside) micelles by using two highly electron-rich contrast agents from biomedical imaging which belong to the families of gadolinium-based and iodinated molecules. The two agents, Gd-HPDO3A and iohexol, were allowed to attain modifications of the solvent electron density that are 50 to 100% higher than those obtained for sucrose, and are located between the electron densities of proteins and RNA/DNA. In the case of Gd-HPDO3A, an analysis of the internal micellar structure was possible and compared with results obtained with sucrose. In conclusion, medical contrast agents represent a promising class of molecules for SAXS contrast-variation experiments with potential appli-cations for numerous soft-matter and biological systems, including membrane proteins and protein-RNA/DNA complexes.
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Affiliation(s)
- Frank Gabel
- IBS, CEA, CNRS, UGA, 71 avenue des Martyrs, 38000 Grenoble, France
| | | | - Javier Pérez
- Synchrotron SOLEIL, Saint-Aubin BP 48, 91192 Gif-sur-Yvette, France
| | - Eric Girard
- IBS, CEA, CNRS, UGA, 71 avenue des Martyrs, 38000 Grenoble, France
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10
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Abstract
Mistakes in the process of cell division can lead to the loss, gain or rearrangement of chromosomes. Significant chromosomal abnormalities are usually lethal to the cells and cause spontaneous miscarriages. However, in some cases, defects in the spindle assembly checkpoint lead to severe diseases, such as cancer and birth and development defects, including Down's syndrome. The timely and accurate control of chromosome segregation in mitosis relies on the spindle assembly checkpoint (SAC), an evolutionary conserved, self-regulated signalling system present in higher organisms. The spindle assembly checkpoint is orchestrated by dynamic interactions between spindle microtubules and the kinetochore , a multiprotein complex that constitutes the site for attachment of chromosomes to microtubule polymers to pull sister chromatids apart during cell division. This chapter discusses the current molecular understanding of the essential, highly dynamic molecular interactions underpinning spindle assembly checkpoint signalling and how the complex choreography of interactions can be coordinated in time and space to finely regulate the process. The potential of targeting this signalling pathway to interfere with the abnormal segregation of chromosomes, which occurs in diverse malignancies and the new opportunities that recent technological developments are opening up for a deeper understanding of the spindle assembly checkpoint are also discussed.
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Affiliation(s)
- Victor M Bolanos-Garcia
- Faculty of Health and Life Sciences, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK.
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11
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Bucciarelli S, Midtgaard SR, Nors Pedersen M, Skou S, Arleth L, Vestergaard B. Size-exclusion chromatography small-angle X-ray scattering of water soluble proteins on a laboratory instrument. J Appl Crystallogr 2018; 51:1623-1632. [PMID: 30546289 PMCID: PMC6276278 DOI: 10.1107/s1600576718014462] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 10/13/2018] [Indexed: 11/16/2022] Open
Abstract
Coupling of size-exclusion chromatography with biological solution small-angle X-ray scattering (SEC-SAXS) on dedicated synchrotron beamlines enables structural analysis of challenging samples such as labile proteins and low-affinity complexes. For this reason, the approach has gained increased popularity during the past decade. Transportation of perishable samples to synchrotrons might, however, compromise the experiments, and the limited availability of synchrotron beamtime renders iterative sample optimization tedious and lengthy. Here, the successful setup of laboratory-based SEC-SAXS is described in a proof-of-concept study. It is demonstrated that sufficient quality data can be obtained on a laboratory instrument with small sample consumption, comparable to typical synchrotron SEC-SAXS demands. UV/vis measurements directly on the SAXS exposure cell ensure accurate concentration determination, crucial for direct molecular weight determination from the scattering data. The absence of radiation damage implies that the sample can be fractionated and subjected to complementary analysis available at the home institution after SEC-SAXS. Laboratory-based SEC-SAXS opens the field for analysis of biological samples at the home institution, thus increasing productivity of biostructural research. It may further ensure that synchrotron beamtime is used primarily for the most suitable and optimized samples.
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Affiliation(s)
- Saskia Bucciarelli
- Department of Drug Design and Pharmacology, University of Copenhagen, Denmark
| | - Søren Roi Midtgaard
- Structural Biophysics, X-ray and Neutron Science, The Niels Bohr Institute, University of Copenhagen, Denmark
| | - Martin Nors Pedersen
- Structural Biophysics, X-ray and Neutron Science, The Niels Bohr Institute, University of Copenhagen, Denmark
| | | | - Lise Arleth
- Structural Biophysics, X-ray and Neutron Science, The Niels Bohr Institute, University of Copenhagen, Denmark
| | - Bente Vestergaard
- Department of Drug Design and Pharmacology, University of Copenhagen, Denmark
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12
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Mitrea DM, Chandra B, Ferrolino MC, Gibbs EB, Tolbert M, White MR, Kriwacki RW. Methods for Physical Characterization of Phase-Separated Bodies and Membrane-less Organelles. J Mol Biol 2018; 430:4773-4805. [PMID: 30017918 PMCID: PMC6503534 DOI: 10.1016/j.jmb.2018.07.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/04/2018] [Accepted: 07/09/2018] [Indexed: 12/17/2022]
Abstract
Membrane-less organelles are cellular structures which arise through the phenomenon of phase separation. This process enables compartmentalization of specific sets of macromolecules (e.g., proteins, nucleic acids), thereby regulating cellular processes by increasing local concentration, and modulating the structure and dynamics of their constituents. Understanding the connection between structure, material properties and function of membrane-less organelles requires inter-disciplinary approaches, which address length and timescales that span several orders of magnitude (e.g., Ångstroms to micrometer, picoseconds to hours). In this review, we discuss the wide variety of methods that have been applied to characterize the morphology, rheology, structure and dynamics of membrane-less organelles and their components, in vitro and in live cells.
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Affiliation(s)
- Diana M Mitrea
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Bappaditya Chandra
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Mylene C Ferrolino
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Eric B Gibbs
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Michele Tolbert
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Michael R White
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Richard W Kriwacki
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN 38163, USA.
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13
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Cai K, Frederick RO, Dashti H, Markley JL. Architectural Features of Human Mitochondrial Cysteine Desulfurase Complexes from Crosslinking Mass Spectrometry and Small-Angle X-Ray Scattering. Structure 2018; 26:1127-1136.e4. [PMID: 29983374 PMCID: PMC6082693 DOI: 10.1016/j.str.2018.05.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/16/2018] [Accepted: 05/24/2018] [Indexed: 11/19/2022]
Abstract
Cysteine desulfurase plays a central role in mitochondrial iron-sulfur cluster biogenesis by generating sulfur through the conversion of L-cysteine to L-alanine and by serving as the platform for assembling other components of the biosynthetic machinery, including ISCU, frataxin, and ferredoxin. The human mitochondrial cysteine desulfurase complex consists of two copies each of NFS1, ISD11, and acyl carrier protein. We describe results from chemical crosslinking coupled with tandem mass spectrometry and small-angle X-ray scattering studies that are consistent with a closed NFS1 dimer rather than an open one for both the cysteine desulfurase-ISCU and cysteine desulfurase-ISCU-frataxin complexes. We present a structural model for the cysteine desulfurase-ISCU-frataxin complex derived from chemical crosslinking restraints in conjunction with the recent crystal structure of the cysteine desulfurase-ISCU-zinc complex and distance constraints from nuclear magnetic resonance.
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Affiliation(s)
- Kai Cai
- Biochemistry Department, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA
| | - Ronnie O Frederick
- Biochemistry Department, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA
| | - Hesam Dashti
- Biochemistry Department, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA
| | - John L Markley
- Biochemistry Department, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA.
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14
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Fairlamb MS, Whitaker AM, Freudenthal BD. Apurinic/apyrimidinic (AP) endonuclease 1 processing of AP sites with 5' mismatches. Acta Crystallogr D Struct Biol 2018; 74:760-768. [PMID: 30082511 PMCID: PMC6079627 DOI: 10.1107/s2059798318003340] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 02/26/2018] [Indexed: 01/17/2023] Open
Abstract
Despite the DNA duplex being central to biological functions, many intricacies of this molecule, including the dynamic nature of mismatched base pairing, are still unknown. The unique conformations adopted by DNA mismatches can provide insight into the forces at play between nucleotides. Moreover, DNA-binding proteins apply their own individualized steric and electrochemical influences on the nucleotides that they interact with, further altering base-pairing conformations. Here, seven X-ray crystallographic structures of the human nuclease apurinic/apyrimidinic (AP) endonuclease 1 (APE1) in complex with its substrate target flanked by a 5' mismatch are reported. The structures reveal how APE1 influences the conformations of a variety of different mismatched base pairs. Purine-purine mismatches containing a guanine are stabilized by a rotation of the guanine residue about the N-glycosidic bond to utilize the Hoogsteen edge for hydrogen bonding. Interestingly, no rotation of adenine, the other purine, is observed. Mismatches involving both purine and pyrimidine bases adopt wobble conformations to accommodate the mismatch. Pyrimidine-pyrimidine mismatches also wobble; however, the smaller profile of a pyrimidine base results in a gap between the Watson-Crick faces that is reduced by a C1'-C1' compression. These results advance our understanding of mismatched base pairing and the influence of a bound protein.
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Affiliation(s)
- Max S. Fairlamb
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66016, USA
| | - Amy M. Whitaker
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66016, USA
| | - Bret D. Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66016, USA
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15
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Thomas M, Schwartz R. A method for efficient Bayesian optimization of self-assembly systems from scattering data. BMC SYSTEMS BIOLOGY 2018; 12:65. [PMID: 29884203 PMCID: PMC5994016 DOI: 10.1186/s12918-018-0592-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 05/24/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND The ability of collections of molecules to spontaneously assemble into large functional complexes is central to all cellular processes. Using the viral capsid as a model system for complicated macro-molecular assembly, we develop methods for probing fine details of the process by learning kinetic rate parameters consistent with experimental measures of assembly. We have previously shown that local rule based stochastic simulation methods in conjunction with bulk indirect experimental data can meaningfully constrain the space of possible assembly trajectories and allow inference of experimentally unobservable features of the real system. RESULTS In the present work, we introduce a new Bayesian optimization framework using multi-Gaussian process model regression. We also extend our prior work to encompass small-angle X-ray/neutron scattering (SAXS/SANS) as a possibly richer experimental data source than the previously used static light scattering (SLS). Method validation is based on synthetic experiments generated using protein data bank (PDB) structures of cowpea chlorotic mottle virus. We also apply the same approach to computationally cheaper differential equation based simulation models. CONCLUSIONS We present a flexible approach for the global optimization of computationally costly objective functions associated with dynamic, multidimensional models. When applied to the stochastic viral capsid system, our method outperforms a current state of the art black box solver tailored for use with noisy objectives. Our approach also has wide applicability to general stochastic optimization problems.
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Affiliation(s)
- Marcus Thomas
- Computational Biology Department, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, USA
| | - Russell Schwartz
- Computational Biology Department, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, USA. .,Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, USA.
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16
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Lubart Q, Vitet H, Dalonneau F, Le Roy A, Kowalski M, Lourdin M, Ebel C, Weidenhaupt M, Picart C. Role of Phosphorylation in Moesin Interactions with PIP 2-Containing Biomimetic Membranes. Biophys J 2018; 114:98-112. [PMID: 29320700 PMCID: PMC5912500 DOI: 10.1016/j.bpj.2017.10.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 10/08/2017] [Accepted: 10/17/2017] [Indexed: 12/26/2022] Open
Abstract
Moesin, a protein of the ezrin, radixin, and moesin family, which links the plasma membrane to the cytoskeleton, is involved in multiple physiological and pathological processes, including viral budding and infection. Its interaction with the plasma membrane occurs via a key phosphoinositide, the phosphatidyl(4,5)inositol-bisphosphate (PIP2), and phosphorylation of residue T558, which has been shown to contribute, in cellulo, to a conformationally open protein. We study the impact of a double phosphomimetic mutation of moesin (T235D, T558D), which mimics the phosphorylation state of the protein, on protein/PIP2/microtubule interactions. Analytical ultracentrifugation in the micromolar range showed moesin in the monomer and dimer forms, with wild-type (WT) moesin containing a slightly larger fraction (∼30%) of dimers than DD moesin (10-20%). Only DD moesin was responsive to PIP2 in its micellar form. Quantitative cosedimentation assays using large unilamellar vesicles and quartz crystal microbalance on supported lipid bilayers containing PIP2 reveal a specific cooperative interaction for DD moesin with an ability to bind two PIP2 molecules simultaneously, whereas WT moesin was able to bind only one. In addition, DD moesin could subsequently interact with microtubules, whereas WT moesin was unable to do so. Altogether, our results point to an important role of these two phosphorylation sites in the opening of moesin: since DD moesin is intrinsically in a more open conformation than WT moesin, this intermolecular interaction is reinforced by its binding to PIP2. We also highlight important differences between moesin and ezrin, which appear to be finely regulated and to exhibit distinct molecular behaviors.
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Affiliation(s)
- Quentin Lubart
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Helene Vitet
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Fabien Dalonneau
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Aline Le Roy
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Mathieu Kowalski
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Morgane Lourdin
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Christine Ebel
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Marianne Weidenhaupt
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Catherine Picart
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France.
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17
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Miura K. An Overview of Current Methods to Confirm Protein-Protein Interactions. Protein Pept Lett 2018; 25:728-733. [PMID: 30129399 PMCID: PMC6204658 DOI: 10.2174/0929866525666180821122240] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 08/11/2018] [Accepted: 08/11/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND The research field of protein-protein interactions is interdisciplinary and specialized field that spans all aspects of biology, physics and chemistry. Therefore, in order to discuss the protein-protein interaction in detail and rigorously, it is desirable to integrate knowledge and methods of many related fields including boundary areas such as biochemistry, biophysics and physical chemistry in addition to biology, physics and chemistry. OBJECTIVE The purpose of this review is to overview current methods to confirm protein-protein interactions. Furthermore, I discuss future prospects of methodology based on current status. RESULTS It is often necessary to integrate, combine and validate multiple results from various methods to understand protein-protein interactions in detail. CONCLUSION It might be desirable for the addition of tags, labeling, and immobilization to solid phases to be unnecessary, and to obtain information on affinity, kinetics, and structure via the analytical method for protein-protein interactions. Therefore, I argue that novel methods based on principles that have already been sufficiently studied in physics or chemistry, but insufficiently applied to the life sciences, should be established to further develop the study of protein-protein interactions.
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Affiliation(s)
- Kenji Miura
- Address correspondence to this author at the Department of Developmental Anatomy and Regenerative Biology, National Defense Medical College, Tokorozawa, Saitama, Japan; Tel: +81 4 2995 1754; E-mail:
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18
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Hopkins JB, Gillilan RE, Skou S. BioXTAS RAW: improvements to a free open-source program for small-angle X-ray scattering data reduction and analysis. J Appl Crystallogr 2017; 50:1545-1553. [PMID: 29021737 PMCID: PMC5627684 DOI: 10.1107/s1600576717011438] [Citation(s) in RCA: 395] [Impact Index Per Article: 56.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 08/02/2017] [Indexed: 01/19/2023] Open
Abstract
BioXTAS RAW is a graphical-user-interface-based free open-source Python program for reduction and analysis of small-angle X-ray solution scattering (SAXS) data. The software is designed for biological SAXS data and enables creation and plotting of one-dimensional scattering profiles from two-dimensional detector images, standard data operations such as averaging and subtraction and analysis of radius of gyration and molecular weight, and advanced analysis such as calculation of inverse Fourier transforms and envelopes. It also allows easy processing of inline size-exclusion chromatography coupled SAXS data and data deconvolution using the evolving factor analysis method. It provides an alternative to closed-source programs such as Primus and ScÅtter for primary data analysis. Because it can calibrate, mask and integrate images it also provides an alternative to synchrotron beamline pipelines that scientists can install on their own computers and use both at home and at the beamline.
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19
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Complementary uses of small angle X-ray scattering and X-ray crystallography. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1623-1630. [PMID: 28743534 DOI: 10.1016/j.bbapap.2017.07.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/10/2017] [Accepted: 07/20/2017] [Indexed: 12/11/2022]
Abstract
Most proteins function within networks and, therefore, protein interactions are central to protein function. Although stable macromolecular machines have been extensively studied, dynamic protein interactions remain poorly understood. Small-angle X-ray scattering probes the size, shape and dynamics of proteins in solution at low resolution and can be used to study samples in a large range of molecular weights. Therefore, it has emerged as a powerful technique to study the structure and dynamics of biomolecular systems and bridge fragmented information obtained using high-resolution techniques. Here we review how small-angle X-ray scattering can be combined with other structural biology techniques to study protein dynamics. This article is part of a Special Issue entitled: Biophysics in Canada, edited by Lewis Kay, John Baenziger, Albert Berghuis and Peter Tieleman.
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20
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Rumancev C, von Gundlach AR, Baier S, Wittstock A, Shi J, Benzi F, Senkbeil T, Stuhr S, Garamusx VM, Grunwaldt JD, Rosenhahn A. Morphological analysis of cerium oxide stabilized nanoporous gold catalysts by soft X-ray ASAXS. RSC Adv 2017. [DOI: 10.1039/c7ra05396g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Soft X-ray SAXS and ASAXS reveal nanostructural properties and temperature induced morphological changes in catalyst materials. The stabilizing effect of cerium oxide deposits on the gold catalyst and the morphological properties of the cerium oxide were determined.
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Affiliation(s)
- C. Rumancev
- Analytical Chemistry – Biointerfaces
- Ruhr-University Bochum
- 44780 Bochum
- Germany
| | - A. R. von Gundlach
- Analytical Chemistry – Biointerfaces
- Ruhr-University Bochum
- 44780 Bochum
- Germany
| | - S. Baier
- Institute for Chemical Technology and Polymer Chemistry
- Karlsruher Institut für Technologie (KIT)
- 76131 Karlsruhe
- Germany
| | - A. Wittstock
- Institute of Applied and Physical Chemistry
- University of Bremen
- 28359 Bremen
- Germany
| | - J. Shi
- Institute of Applied and Physical Chemistry
- University of Bremen
- 28359 Bremen
- Germany
| | - F. Benzi
- Institute for Chemical Technology and Polymer Chemistry
- Karlsruher Institut für Technologie (KIT)
- 76131 Karlsruhe
- Germany
| | - T. Senkbeil
- Analytical Chemistry – Biointerfaces
- Ruhr-University Bochum
- 44780 Bochum
- Germany
| | - S. Stuhr
- Analytical Chemistry – Biointerfaces
- Ruhr-University Bochum
- 44780 Bochum
- Germany
| | - V. M. Garamusx
- Helmholtz-Zentrum Geesthacht
- Zentrum für Material und Küstenforschung GmbH
- 21502 Geesthacht
- Germany
| | - J.-D. Grunwaldt
- Institute for Chemical Technology and Polymer Chemistry
- Karlsruher Institut für Technologie (KIT)
- 76131 Karlsruhe
- Germany
| | - A. Rosenhahn
- Analytical Chemistry – Biointerfaces
- Ruhr-University Bochum
- 44780 Bochum
- Germany
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21
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Gabel F. Applications of SANS to Study Membrane Protein Systems. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1009:201-214. [DOI: 10.1007/978-981-10-6038-0_12] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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22
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Tokuda JM, Pabit SA, Pollack L. Protein-DNA and ion-DNA interactions revealed through contrast variation SAXS. Biophys Rev 2016; 8:139-149. [PMID: 27551324 PMCID: PMC4991782 DOI: 10.1007/s12551-016-0196-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 03/10/2016] [Indexed: 12/29/2022] Open
Abstract
Understanding how DNA carries out its biological roles requires knowledge of its interactions with biological partners. Since DNA is a polyanionic polymer, electrostatic interactions contribute significantly. These interactions are mediated by positively charged protein residues or charge compensating cations. Direct detection of these partners and/or their effect on DNA conformation poses challenges, especially for monitoring conformational dynamics in real time. Small-angle x-ray scattering (SAXS) is uniquely sensitive to both the conformation and local environment (i.e. protein partner and associated ions) of the DNA. The primary challenge of studying multi-component systems with SAXS lies in resolving how each component contributes to the measured scattering. Here, we review two contrast variation (CV) strategies that enable targeted studies of the structures of DNA or its associated partners. First, solution contrast variation enables measurement of DNA conformation within a protein-DNA complex by masking out the protein contribution to the scattering profile. We review a specific example, in which the real-time unwrapping of DNA from a nucleosome core particle is measured during salt-induced disassembly. The second method, heavy atom isomorphous replacement, reports the spatial distribution of the cation cloud around duplex DNA by exploiting changes in the scattering strength of cations with varying atomic numbers. We demonstrate the application of this approach to provide the spatial distribution of monovalent cations (Na+, K+, Rb+, Cs+) around a standard 25-base pair DNA. The CV strategies presented here are valuable tools for understanding DNA interactions with its biological partners.
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Affiliation(s)
- Joshua M. Tokuda
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853 USA
| | - Suzette A. Pabit
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853 USA
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853 USA
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23
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Application of advanced X-ray methods in life sciences. Biochim Biophys Acta Gen Subj 2016; 1861:3671-3685. [PMID: 27156488 DOI: 10.1016/j.bbagen.2016.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 05/03/2016] [Accepted: 05/04/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Synchrotron radiation (SR) sources provide diverse X-ray methods for the investigation of structure-function relationships in biological macromolecules. SCOPE OF REVIEW Recent developments in SR sources and in the X-ray tools they offer for life sciences are reviewed. Specifically, advances in macromolecular crystallography, small angle X-ray solution scattering, X-ray absorption and fluorescence spectroscopy, and imaging are discussed with examples. MAJOR CONCLUSIONS SR sources offer a range of X-ray techniques that can be used in a complementary fashion in studies of biological systems at a wide range of resolutions from atomic to cellular scale. Emerging applications of X-ray techniques include the characterization of disordered proteins, noncrystalline and nonequilibrium systems, elemental imaging of tissues, cells and organs, and detection of time-resolved changes in molecular structures. GENERAL SIGNIFICANCE X-ray techniques are in the center of hybrid approaches that are used to gain insight into complex problems relating to biomolecular mechanisms, disease and possible therapeutic solutions. This article is part of a Special Issue entitled "Science for Life". Guest Editors: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo.
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24
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Chen Y, Pollack L. SAXS studies of RNA: structures, dynamics, and interactions with partners. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:512-26. [PMID: 27071649 DOI: 10.1002/wrna.1349] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/11/2016] [Accepted: 03/01/2016] [Indexed: 12/29/2022]
Abstract
Small-angle X-ray scattering, SAXS, is a powerful and easily employed experimental technique that provides solution structures of macromolecules. The size and shape parameters derived from SAXS provide global structural information about these molecules in solution and essentially complement data acquired by other biophysical methods. As applied to protein systems, SAXS is a relatively mature technology: sophisticated tools exist to acquire and analyze data, and to create structural models that include dynamically flexible ensembles. Given the expanding appreciation of RNA's biological roles, there is a need to develop comparable tools to characterize solution structures of RNA, including its interactions with important biological partners. We review the progress toward achieving this goal, focusing on experimental and computational innovations. The use of multiphase modeling, absolute calibration and contrast variation methods, among others, provides new and often unique ways of visualizing this important biological molecule and its essential partners: ions, other RNAs, or proteins. WIREs RNA 2016, 7:512-526. doi: 10.1002/wrna.1349 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Yujie Chen
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
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