1
|
Ahlgren K, Havemeister F, Andersson J, Esbjörner EK, Swenson J. The inhibition of fibril formation of lysozyme by sucrose and trehalose. RSC Adv 2024; 14:11921-11931. [PMID: 38623289 PMCID: PMC11017192 DOI: 10.1039/d4ra01171f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/03/2024] [Indexed: 04/17/2024] Open
Abstract
The two disaccharides, trehalose and sucrose, have been compared in many studies due to their structural similarity. Both possess the ability to stabilise and reduce aggregation of proteins. Trehalose has also been shown to inhibit the formation of highly structured protein aggregates called amyloid fibrils. This study aims to compare how the thermal stability of the protein lysozyme at low pH (2.0 and 3.5) is affected by the presence of the two disaccharides. We also address the anti-aggregating properties of the disaccharides and their inhibitory effects on fibril formation. Differential scanning calorimetry confirms that the thermal stability of lysozyme is increased by the presence of trehalose or sucrose. The effect is slightly larger for sucrose. The inhibiting effects on protein aggregation are investigated using small-angle X-ray scattering which shows that the two-component system consisting of lysozyme and water (Lys/H2O) at pH 2.0 contains larger aggregates than the corresponding system at pH 3.5 as well as the sugar containing systems. In addition, the results show that the particle-to-particle distance in the sugar containing systems (Lys/Tre/H2O and Lys/Suc/H2O) at pH 2.0 is longer than at pH 3.5, suggesting larger protein aggregates in the former. Finally, the characteristic distance separating β-strands in amyloid fibrils is observed for the Lys/H2O system at pH 2.0, using wide-angle X-ray scattering, while it is not clearly observed for the sugar containing systems. This study further shows that the two disaccharides stabilise the native fold of lysozyme by increasing the denaturation temperature. However, other factors, such as a weakening of hydrophobic interactions and hydrogen bonding between proteins, might also play a role in their inhibitory effect on amyloid fibril formation.
Collapse
Affiliation(s)
- Kajsa Ahlgren
- Division of Nano-Biophysics, Department of Physics, Chalmers University of Technology Gothenburg SE-412 96 Sweden
| | - Fritjof Havemeister
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology Gothenburg SE-412 96 Sweden
| | - Julia Andersson
- Division of Nano-Biophysics, Department of Physics, Chalmers University of Technology Gothenburg SE-412 96 Sweden
| | - Elin K Esbjörner
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology Gothenburg SE-412 96 Sweden
| | - Jan Swenson
- Division of Nano-Biophysics, Department of Physics, Chalmers University of Technology Gothenburg SE-412 96 Sweden
| |
Collapse
|
2
|
Blanc M, Lettl C, Guérin J, Vieille A, Furler S, Briand-Schumacher S, Dreier B, Bergé C, Plückthun A, Vadon-Le Goff S, Fronzes R, Rousselle P, Fischer W, Terradot L. Designed Ankyrin Repeat Proteins provide insights into the structure and function of CagI and are potent inhibitors of CagA translocation by the Helicobacter pylori type IV secretion system. PLoS Pathog 2023; 19:e1011368. [PMID: 37155700 DOI: 10.1371/journal.ppat.1011368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 05/18/2023] [Accepted: 04/18/2023] [Indexed: 05/10/2023] Open
Abstract
The bacterial human pathogen Helicobacter pylori produces a type IV secretion system (cagT4SS) to inject the oncoprotein CagA into gastric cells. The cagT4SS external pilus mediates attachment of the apparatus to the target cell and the delivery of CagA. While the composition of the pilus is unclear, CagI is present at the surface of the bacterium and required for pilus formation. Here, we have investigated the properties of CagI by an integrative structural biology approach. Using Alpha Fold 2 and Small Angle X-ray scattering, it was found that CagI forms elongated dimers mediated by rod-shape N-terminal domains (CagIN) prolonged by globular C-terminal domains (CagIC). Three Designed Ankyrin Repeat Proteins (DARPins) K2, K5 and K8 selected against CagI interacted with CagIC with subnanomolar affinities. The crystal structures of the CagI:K2 and CagI:K5 complexes were solved and identified the interfaces between the molecules, thereby providing a structural explanation for the difference in affinity between the two binders. Purified CagI and CagIC were found to interact with adenocarcinoma gastric (AGS) cells, induced cell spreading and the interaction was inhibited by K2. The same DARPin inhibited CagA translocation by up to 65% in AGS cells while inhibition levels were 40% and 30% with K8 and K5, respectively. Our study suggests that CagIC plays a key role in cagT4SS-mediated CagA translocation and that DARPins targeting CagI represent potent inhibitors of the cagT4SS, a crucial risk factor for gastric cancer development.
Collapse
Affiliation(s)
- Marine Blanc
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
| | - Clara Lettl
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Jérémy Guérin
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
| | - Anaïs Vieille
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
| | - Sven Furler
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | | | - Birgit Dreier
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Célia Bergé
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
| | - Andreas Plückthun
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Sandrine Vadon-Le Goff
- University of Lyon, CNRS UMR5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), Lyon, France
| | - Rémi Fronzes
- European Institute of Chemistry and Biology, CNRS UMR 5234 Microbiologie Fondamentale et Pathogénicité, Univ. Bordeaux, Pessac, France
| | - Patricia Rousselle
- University of Lyon, CNRS UMR5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), Lyon, France
| | - Wolfgang Fischer
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Laurent Terradot
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
| |
Collapse
|
3
|
Cohen T, Halfon M, Carter L, Sharkey B, Jain T, Sivasubramanian A, Schneidman-Duhovny D. Multi-state modeling of antibody-antigen complexes with SAXS profiles and deep-learning models. Methods Enzymol 2022; 678:237-262. [PMID: 36641210 DOI: 10.1016/bs.mie.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Antibodies are an established class of human therapeutics. Epitope characterization is an important part of therapeutic antibody discovery. However, structural characterization of antibody-antigen complexes remains challenging. On the one hand, X-ray crystallography or cryo-electron microscopy provide atomic resolution characterization of the epitope, but the data collection process is typically long and the success rate is low. On the other hand, computational methods for modeling antibody-antigen structures from the individual components frequently suffer from a high false positive rate, rarely resulting in a unique solution. Recent deep learning models for structure prediction are also successful in predicting protein-protein complexes. However, they do not perform well for antibody-antigen complexes. Small Angle X-ray Scattering (SAXS) is a reliable technique for rapid structural characterization of protein samples in solution albeit at low resolution. Here, we present an integrative approach for modeling antigen-antibody complexes using the antibody sequence, antigen structure, and experimentally determined SAXS profiles of the antibody, antigen, and the complex. The method models antibody structures using a novel deep-learning approach, NanoNet. The structures of the antibodies and antigens are represented using multiple 3D conformations to account for compositional and conformational heterogeneity of the protein samples that are used to collect the SAXS data. The complexes are predicted by integrating the SAXS profiles with scoring functions for protein-protein interfaces that are based on statistical potentials and antibody-specific deep-learning models. We validated the method via application to four Fab:EGFR and one Fab:PCSK9 antibody:antigen complexes with experimentally available SAXS datasets. The integrative approach returns accurate predictions (interface RMSD<4Å) in the top five predictions for four out of five complexes (respective interface RMSD values of 1.95, 2.18, 2.66 and 3.87Å), providing support for the utility of such a computational pipeline for epitope characterization during therapeutic antibody discovery.
Collapse
Affiliation(s)
- Tomer Cohen
- The Rachel and Selim Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Matan Halfon
- The Rachel and Selim Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Lester Carter
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, United States
| | - Beth Sharkey
- High-Throughput Expression, Adimab LLC, Lebanon, NH, United States
| | - Tushar Jain
- Computational Biology, Adimab LLC, Palo Alto, CA, United States
| | | | - Dina Schneidman-Duhovny
- The Rachel and Selim Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel.
| |
Collapse
|
4
|
Gao S, Klinman JP. Functional roles of enzyme dynamics in accelerating active site chemistry: Emerging techniques and changing concepts. Curr Opin Struct Biol 2022; 75:102434. [PMID: 35872562 PMCID: PMC9901422 DOI: 10.1016/j.sbi.2022.102434] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/15/2022] [Accepted: 06/21/2022] [Indexed: 02/08/2023]
Abstract
With the growing acceptance of the contribution of protein conformational ensembles to enzyme catalysis and regulation, research in the field of protein dynamics has shifted toward an understanding of the atomistic properties of protein dynamical networks and the mechanisms and time scales that control such behavior. A full description of an enzymatic reaction coordinate is expected to extend beyond the active site and include site-specific networks that communicate with the protein/water interface. Advances in experimental tools for the spatial resolution of thermal activation pathways are being complemented by biophysical methods for visualizing dynamics in real time. An emerging multidimensional model integrates the impacts of bound substrate/effector on the distribution of protein substates that are in rapid equilibration near room temperature with reaction-specific protein embedded heat transfer conduits.
Collapse
Affiliation(s)
- Shuaihua Gao
- Department of Chemistry, University of California, Berkeley, CA, 94720, United States; California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, United States. https://twitter.com/S_H_Gao
| | - Judith P Klinman
- Department of Chemistry, University of California, Berkeley, CA, 94720, United States; California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, United States; Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, United States.
| |
Collapse
|
5
|
Casado-Combreras MÁ, Rivero-Rodríguez F, Elena-Real CA, Molodenskiy D, Díaz-Quintana A, Martinho M, Gerbaud G, González-Arzola K, Velázquez-Campoy A, Svergun D, Belle V, De la Rosa MA, Díaz-Moreno I. PP2A is activated by cytochrome c upon formation of a diffuse encounter complex with SET/TAF-Iβ. Comput Struct Biotechnol J 2022; 20:3695-3707. [PMID: 35891793 PMCID: PMC9293736 DOI: 10.1016/j.csbj.2022.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 07/04/2022] [Accepted: 07/04/2022] [Indexed: 11/25/2022] Open
Abstract
Intrinsic protein flexibility is of overwhelming relevance for intermolecular recognition and adaptability of highly dynamic ensemble of complexes, and the phenomenon is essential for the understanding of numerous biological processes. These conformational ensembles-encounter complexes-lack a unique organization, which prevents the determination of well-defined high resolution structures. This is the case for complexes involving the oncoprotein SET/template-activating factor-Iβ (SET/TAF-Iβ), a histone chaperone whose functions and interactions are significantly affected by its intrinsic structural plasticity. Besides its role in chromatin remodeling, SET/TAF-Iβ is an inhibitor of protein phosphatase 2A (PP2A), which is a key phosphatase counteracting transcription and signaling events controlling the activity of DNA damage response (DDR) mediators. During DDR, SET/TAF-Iβ is sequestered by cytochrome c (Cc) upon migration of the hemeprotein from mitochondria to the cell nucleus. Here, we report that the nuclear SET/TAF-Iβ:Cc polyconformational ensemble is able to activate PP2A. In particular, the N-end folded, globular region of SET/TAF-Iβ (a.k.a. SET/TAF-Iβ ΔC)-which exhibits an unexpected, intrinsically highly dynamic behavior-is sufficient to be recognized by Cc in a diffuse encounter manner. Cc-mediated blocking of PP2A inhibition is deciphered using an integrated structural and computational approach, combining small-angle X-ray scattering, electron paramagnetic resonance, nuclear magnetic resonance, calorimetry and molecular dynamics simulations.
Collapse
Key Words
- ANP32B, Acidic leucine-rich nuclear phosphoprotein family member B
- BTFA, 3-bromo-1,1,1-trifluoroacetone
- CD, Circular dichroism
- CDK9, Cyclin-dependent kinase 9
- CW, Continuous wave
- Cc, Cytochrome c
- Cytochrome c
- DDR, DNA damage response
- DEER, Double electron–electron resonance
- DLS, Dynamic light scattering
- DMEM, Dulbecco’s modified Eagle’s medium
- DNA, Deoxyribonucleic acid
- DTT, Dithiotreitol
- Dmax, Maximum dimension
- EDTA, Ethylenediamine tetraacetic acid
- EGTA, Ethyleneglycol tetraacetic acid
- EPR, Electron paramagnetic resonance
- Encounter complex
- FBS, Fetal bovine serum
- GUI, Graphical user interface
- HEK, Human embryonic kidney cells
- HRP, Horseradish peroxidase
- I2PP2A, Inhibitor 2 of the protein phosphatase 2A
- I3PP2A, Inhibitor 3 of the protein phosphatase 2A
- INTAC, Integrator-PP2A complex
- IPTG, Isopropyl-β-D-1-thiogalactopyranoside
- ITC, Isothermal titration calorimetry
- Ip/Id, Intensity ratio of NMR resonances between paramagnetic and diamagnetic samples
- LB, Luria-Bertani
- MD, Molecular dynamics
- MTS, (1-acetoxy-2,2,5,5-tetramethyl-δ-3-pyrroline-3-methyl) methanethiosulfonate
- MTSL, (1-oxyl-2,2,5,5-tetramethyl- δ −3-pyrroline-3-methyl) methanethiosulfonate
- MW, Molecular weight
- Molecular dynamics
- NAP1, Nucleosome assembly protein 1
- NAPL, Nucleosome assembly protein L
- NMA, Normal mode analysis
- NMR, Nuclear magnetic resonance
- NPT, Constant number, pressure and temperature
- NVT, Constant number, volume and temperature
- Nuclear magnetic resonance
- OD600, Optical density measured at 600 nm
- OPC, Optimal 3-charge, 4-point rigid water model
- PCR, Polymerase chain reaction
- PME, Particle mesh Ewald
- PMSF, Phenylmethylsulfonyl fluoride
- PP2A, Protein phosphatase 2A
- PRE, Paramagnetic relaxation enhancement
- PVDF, Polyvinylidene fluoride
- Protein phosphatase 2A
- RNA, Ribonucleic acid
- RNApol II, RNA polymerase II
- Rg, Radius of gyration
- SAXS, Small-angle X-ray scattering
- SC, Sample changer
- SDS-PAGE, Sodium dodecylsulfate-polyacrylamide gel electrophoresis
- SDSL, Site-directed spin labeling
- SEC, Size-exclusion chromatography
- SET/TAF-Iβ
- SET/TAF-Iβ ΔC, SET/template-activating factor-Iβ construct lacking its C-terminal domain
- SET/TAF-Iβ, SET/template-activating factor-Iβ
- SPRi, Surface plasmon resonance imaging
- TAF-Iα, Template-activating factor-Iα
- TPBS, Tween 20-phosphate buffered saline
- VPS75, Vacuolar protein sorting-associated protein 75
- WT, Wild type
- XRD, X-ray diffraction
Collapse
Affiliation(s)
- Miguel Á. Casado-Combreras
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
| | - Francisco Rivero-Rodríguez
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
| | - Carlos A. Elena-Real
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
- Centre de Biologie Structurale (CBS), INSERM, Centre National de la Recherche Scientifique (CNRS) and Université de Montpellier. 29 rue de Navacelles, 34090 Montpellier, France
| | - Dmitry Molodenskiy
- European Molecular Biology Laboratory, Hamburg Outstation, c/o Deutsches Elektronen-Synchrotron, Notkestr. 85, 22607 Hamburg, Germany
| | - Antonio Díaz-Quintana
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
| | - Marlène Martinho
- Aix Marseille Univ. Centre National de la Recherche Scientifique (CNRS), BIP UMR7281, Bioénergétique et Ingénierie des protéines, 13402 Marseille, France
| | - Guillaume Gerbaud
- Aix Marseille Univ. Centre National de la Recherche Scientifique (CNRS), BIP UMR7281, Bioénergétique et Ingénierie des protéines, 13402 Marseille, France
| | - Katiuska González-Arzola
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
| | - Adrián Velázquez-Campoy
- Institute of Biocomputation and Physic of Complex Systems (BIFI), Joint Unit GBsC-CSIC-BIFI, Universidad de Zaragoza. C. de Mariano Esquillor Gómez, Edificio I+D, 50018 Zaragoza, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, C. Pedro Cerbuna, 12, 50009 Zaragoza, Spain
- Instituto de Investigación Sanitaria de Aragón (IIS Aragon), Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), C. de Melchor Fernández Almagro, 3, 28029 Madrid, Spain
| | - Dmitri Svergun
- European Molecular Biology Laboratory, Hamburg Outstation, c/o Deutsches Elektronen-Synchrotron, Notkestr. 85, 22607 Hamburg, Germany
| | - Valérie Belle
- Aix Marseille Univ. Centre National de la Recherche Scientifique (CNRS), BIP UMR7281, Bioénergétique et Ingénierie des protéines, 13402 Marseille, France
| | - Miguel A. De la Rosa
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
| | - Irene Díaz-Moreno
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
| |
Collapse
|
6
|
Han ZZ, Kang SG, Arce L, Westaway D. Prion-like strain effects in tauopathies. Cell Tissue Res 2022; 392:179-199. [PMID: 35460367 PMCID: PMC9034081 DOI: 10.1007/s00441-022-03620-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 03/25/2022] [Indexed: 12/30/2022]
Abstract
Tau is a microtubule-associated protein that plays crucial roles in physiology and pathophysiology. In the realm of dementia, tau protein misfolding is associated with a wide spectrum of clinicopathologically diverse neurodegenerative diseases, collectively known as tauopathies. As proposed by the tau strain hypothesis, the intrinsic heterogeneity of tauopathies may be explained by the existence of structurally distinct tau conformers, “strains”. Tau strains can differ in their associated clinical features, neuropathological profiles, and biochemical signatures. Although prior research into infectious prion proteins offers valuable lessons for studying how a protein-only pathogen can encompass strain diversity, the underlying mechanism by which tau subtypes are generated remains poorly understood. Here we summarize recent advances in understanding different tau conformers through in vivo and in vitro experimental paradigms, and the implications of heterogeneity of pathological tau species for drug development.
Collapse
Affiliation(s)
- Zhuang Zhuang Han
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada.,Department of Medicine, University of Alberta, Edmonton, AB, Canada.,Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - Sang-Gyun Kang
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada.,Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Luis Arce
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada.,Department of Medicine, University of Alberta, Edmonton, AB, Canada.,Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - David Westaway
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada. .,Department of Medicine, University of Alberta, Edmonton, AB, Canada. .,Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.
| |
Collapse
|
7
|
He W, Henning-Knechtel A, Kirmizialtin S. Visualizing RNA Structures by SAXS-Driven MD Simulations. FRONTIERS IN BIOINFORMATICS 2022; 2:781949. [PMID: 36304317 PMCID: PMC9580860 DOI: 10.3389/fbinf.2022.781949] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/04/2022] [Indexed: 12/26/2022] Open
Abstract
The biological role of biomolecules is intimately linked to their structural dynamics. Experimental or computational techniques alone are often insufficient to determine accurate structural ensembles in atomic detail. We use all-atom molecular dynamics (MD) simulations and couple it to small-angle X-ray scattering (SAXS) experiments to resolve the structural dynamics of RNA molecules. To accomplish this task, we utilize a set of re-weighting and biasing techniques tailored for RNA molecules. To showcase our approach, we study two RNA molecules: a riboswitch that shows structural variations upon ligand binding, and a two-way junction RNA that displays structural heterogeneity and sensitivity to salt conditions. Integration of MD simulations and experiments allows the accurate construction of conformational ensembles of RNA molecules. We observe a dynamic change of the SAM-I riboswitch conformations depending on its binding partners. The binding of SAM and Mg2+ cations stabilizes the compact state. The absence of Mg2+ or SAM leads to the loss of tertiary contacts, resulting in a dramatic expansion of the riboswitch conformations. The sensitivity of RNA structures to the ionic strength demonstrates itself in the helix junction helix (HJH). The HJH shows non-monotonic compaction as the ionic strength increases. The physics-based picture derived from the experimentally guided MD simulations allows biophysical characterization of RNA molecules. All in all, SAXS-guided MD simulations offer great prospects for studying RNA structural dynamics.
Collapse
Affiliation(s)
- Weiwei He
- Chemistry Program, Science Division, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
- Department of Chemistry, New York University, New York, NY, United States
| | - Anja Henning-Knechtel
- Chemistry Program, Science Division, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Serdal Kirmizialtin
- Chemistry Program, Science Division, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
- *Correspondence: Serdal Kirmizialtin,
| |
Collapse
|
8
|
Analysis of the nano and microstructures of the cervical cementum and saliva in periodontitis: A pilot study. J Oral Biosci 2021; 63:370-377. [PMID: 34583024 DOI: 10.1016/j.job.2021.09.007] [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: 08/03/2021] [Revised: 09/13/2021] [Accepted: 09/16/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVES During the progression of periodontitis, the structures of the cementum and saliva are altered due to pathological changes in the environment. This study aimed to analyze the nanostructures of the cervical cementum and saliva in patients with periodontitis. METHODS Patients with periodontitis (n = 10) and periodontally healthy controls (n = 8) were included. Single-rooted teeth with indications for extraction were obtained from individuals. The cervical-thirds of the roots were sectioned transversely to obtain 1 mm thick sections. Unstimulated whole saliva samples were collected from each individual. The nanostructures of the cementum and saliva were analyzed using small and wide-angle X-ray scattering methods. RESULTS The mean radius and distance values of the cementum nanoparticles in the periodontitis and control groups were 368 Å and 1152 Å, and 377 Å and 1186 Å, respectively. The mean radius and distance values of the saliva nanoparticles in the periodontitis and control groups were 425 Å and 1359 Å, and 468 Å and 1452 Å, respectively. More wide-angle X-ray scattering profile peaks were observed in the cementum of the controls. Similarities were observed between the 3D profiles of the cementum and the saliva nanoparticles. CONCLUSIONS According to the results of the present study, (i) the cementum and saliva nanoparticles were of similar size in periodontitis and healthy controls, (ii) the cementum was more crystalline according to the (002) crystallographic plane in controls, and (iii) the similarities in the 3D-profile of the cementum and saliva nanoparticles suggest some interactions between them in the sulcus/periodontal pocket at the nanolevel.
Collapse
|
9
|
Gupta A, Shrivastava D, Shakya AK, Gupta K, Pratap JV, Habib S. PfKsgA1 functions as a transcription initiation factor and interacts with the N-terminal region of the mitochondrial RNA polymerase of Plasmodium falciparum. Int J Parasitol 2020; 51:23-37. [PMID: 32896572 DOI: 10.1016/j.ijpara.2020.07.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/13/2020] [Accepted: 07/16/2020] [Indexed: 10/23/2022]
Abstract
The small mitochondrial genome (mtDNA) of the malaria parasite is known to transcribe its genes polycistonically, although promoter element(s) have not yet been identified. An unusually large Plasmodium falciparum candidate mitochondrial phage-like RNA polymerase (PfmtRNAP) with an extended N-terminal region is encoded by the parasite nuclear genome. Using specific antibodies against the enzyme, we established that PfmtRNAP was targeted exclusively to the mitochondrion and interacted with mtDNA. Phylogenetic analysis showed that it is part of a separate apicomplexan clade. A search for PfmtRNAP-associated transcription initiation factors using sequence homology and in silico protein-protein interaction network analysis identified PfKsgA1. PfKsgA1 is a dual cytosol- and mitochondrion-targeted protein that functions as a small subunit rRNA dimethyltransferase in ribosome biogenesis. Chromatin immunoprecipitation showed that PfKsgA1 interacts with mtDNA, and in vivo crosslinking and pull-down experiments confirmed PfmtRNAP-PfKsgA1 interaction. The ability of PfKsgA1 to serve as a transcription initiation factor was demonstrated by complementation of yeast mitochondrial transcription factor Mtf1 function in Rpo41-driven in vitro transcription. Pull-down experiments using PfKsgA1 and PfmtRNAP domains indicated that the N-terminal region of PfmtRNAP interacts primarily with the PfKsgA1 C-terminal domain with some contacts being made with the linker and N-terminal domain of PfKsgA1. In the absence of full-length recombinant PfmtRNAP, solution structures of yeast mitochondrial RNA polymerase Rpo41 complexes with Mtf1 or PfKsgA1 were determined by small-angle X-ray scattering. Protein interaction interfaces thus identified matched with those reported earlier for Rpo41-Mtf1 interaction and overlaid with the PfmtRNAP-interfacing region identified experimentally for PfKsgA1. Our results indicate that in addition to a role in mitochondrial ribosome biogenesis, PfKsgA1 has an independent function as a transcription initiation factor for PfmtRNAP.
Collapse
Affiliation(s)
- Ankit Gupta
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Deepti Shrivastava
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow 226031, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Anil Kumar Shakya
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Kirti Gupta
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - J V Pratap
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Saman Habib
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow 226031, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
| |
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|
11
|
le Maire A, Germain P, Bourguet W. Protein-protein interactions in the regulation of RAR–RXR heterodimers transcriptional activity. Methods Enzymol 2020; 637:175-207. [DOI: 10.1016/bs.mie.2020.02.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
12
|
White MA, Tsalkova T, Mei FC, Cheng X. Conformational States of Exchange Protein Directly Activated by cAMP (EPAC1) Revealed by Ensemble Modeling and Integrative Structural Biology. Cells 2019; 9:cells9010035. [PMID: 31877746 PMCID: PMC7016869 DOI: 10.3390/cells9010035] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/16/2019] [Accepted: 12/18/2019] [Indexed: 02/08/2023] Open
Abstract
Exchange proteins directly activated by cAMP (EPAC1 and EPAC2) are important allosteric regulators of cAMP-mediated signal transduction pathways. To understand the molecular mechanism of EPAC activation, we performed detailed Small-Angle X-ray Scattering (SAXS) analysis of EPAC1 in its apo (inactive), cAMP-bound, and effector (Rap1b)-bound states. Our study demonstrates that we can model the solution structures of EPAC1 in each state using ensemble analysis and homology models derived from the crystal structures of EPAC2. The N-terminal domain of EPAC1, which is not conserved between EPAC1 and EPAC2, appears folded and interacts specifically with another component of EPAC1 in each state. The apo-EPAC1 state is a dynamic mixture of a compact (Rg = 32.9 Å, 86%) and a more extended (Rg = 38.5 Å, 13%) conformation. The cAMP-bound form of EPAC1 in the absence of Rap1 forms a dimer in solution; but its molecular structure is still compatible with the active EPAC1 conformation of the ternary complex model with cAMP and Rap1. Herein, we show that SAXS can elucidate the conformational states of EPAC1 activation as it proceeds from the compact, inactive apo conformation through a previously unknown intermediate-state, to the extended cAMP-bound form, and then binds to its effector (Rap1b) in a ternary complex.
Collapse
Affiliation(s)
- Mark Andrew White
- Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX 77555, USA
- Correspondence: (M.A.W.); (X.C.); Tel.: +409-747-4747 (M.A.W.); +713-500-7487 (X.C.)
| | - Tamara Tsalkova
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, TX 77555, USA;
| | - Fang C. Mei
- Department of Integrative Biology & Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA;
- Texas Therapeutics Institute, Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Xiaodong Cheng
- Department of Integrative Biology & Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA;
- Texas Therapeutics Institute, Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Correspondence: (M.A.W.); (X.C.); Tel.: +409-747-4747 (M.A.W.); +713-500-7487 (X.C.)
| |
Collapse
|
13
|
Abstract
The biological functions of RNA range from gene regulation through catalysis and depend critically on its structure and flexibility. Conformational variations of flexible, non-base-paired components, including RNA hinges, bulges, or single-stranded tails, are well documented. Recent work has also identified variations in the structure of ubiquitous, base-paired duplexes found in almost all functional RNAs. Duplexes anchor the structures of folded RNAs, and their surface features are recognized by partner molecules. To date, no consistent picture has been obtained that describes the range of conformations assumed by RNA duplexes. Here, we apply wide angle, solution X-ray scattering (WAXS) to quantify these variations, by sampling length scales characteristic of helical geometries under different solution conditions. To identify the radius, helical rise, twist, and length of dsRNA helices, we exploit molecular dynamics generated structures, explicit solvent models, and ensemble optimization methods. Our results quantify the substantial and salt-dependent deviations of double-stranded (ds) RNA duplexes from the assumed canonical A-form conformation. Recent experiments underscore the need to properly describe the structures of RNA duplexes when interpreting the salt dependence of RNA conformations.
Collapse
Affiliation(s)
- Yen-Lin Chen
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853
| |
Collapse
|
14
|
Khurana L, ElGindi M, Tilstam PV, Pantouris G. Elucidating the role of an immunomodulatory protein in cancer: From protein expression to functional characterization. Methods Enzymol 2019; 629:307-360. [PMID: 31727247 DOI: 10.1016/bs.mie.2019.05.053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Several fundamental discoveries made over the last two decades, in the field of cancer biology, have increased our understanding of the complex tumor micro- and macroenvironments. This has shifted the current empirical cancer therapies to more rationalized treatments targeting immunomodulatory proteins. From the point of identification, a protein target undergoes several interrogations, which are necessary to truly define its druggability. Here, we outline some basic steps that can be followed for in vitro characterization of a potential immunomodulatory protein target. We describe procedures for recombinant protein expression and purification including key annotations on protein cloning, expression systems, purification strategies and protein characterization using structural and biochemical approaches. For functional characterization, we provide detailed protocols for using flow-cytometric techniques in cell lines or primary cells to study protein expression profiles, proliferation, apoptosis and cell-cycle changes. This multilevel approach can provide valuable, in-depth understanding of any protein target with potential immunomodulatory effects.
Collapse
Affiliation(s)
- Leepakshi Khurana
- Department of Pharmacology, School of Medicine, Yale University, New Haven, CT, United States
| | - Mei ElGindi
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Pathricia V Tilstam
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Georgios Pantouris
- Department of Pharmacology, School of Medicine, Yale University, New Haven, CT, United States; Department of Chemistry, University of the Pacific, Stockton, CA, United States.
| |
Collapse
|
15
|
Braitbard M, Schneidman-Duhovny D, Kalisman N. Integrative Structure Modeling: Overview and Assessment. Annu Rev Biochem 2019; 88:113-135. [PMID: 30830798 DOI: 10.1146/annurev-biochem-013118-111429] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Integrative structure modeling computationally combines data from multiple sources of information with the aim of obtaining structural insights that are not revealed by any single approach alone. In the first part of this review, we survey the commonly used sources of structural information and the computational aspects of model building. Throughout the past decade, integrative modeling was applied to various biological systems, with a focus on large protein complexes. Recent progress in the field of cryo-electron microscopy (cryo-EM) has resolved many of these complexes to near-atomic resolution. In the second part of this review, we compare a range of published integrative models with their higher-resolution counterparts with the aim of critically assessing their accuracy. This comparison gives a favorable view of integrative modeling and demonstrates its ability to yield accurate and informative results. We discuss possible roles of integrative modeling in the new era of cryo-EM and highlight future challenges and directions.
Collapse
Affiliation(s)
- Merav Braitbard
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel;
| | - Dina Schneidman-Duhovny
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; .,School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel;
| | - Nir Kalisman
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel;
| |
Collapse
|
16
|
Computational modeling of RNA 3D structure based on experimental data. Biosci Rep 2019; 39:BSR20180430. [PMID: 30670629 PMCID: PMC6367127 DOI: 10.1042/bsr20180430] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 01/19/2019] [Accepted: 01/21/2019] [Indexed: 01/02/2023] Open
Abstract
RNA molecules are master regulators of cells. They are involved in a variety of molecular processes: they transmit genetic information, sense cellular signals and communicate responses, and even catalyze chemical reactions. As in the case of proteins, RNA function is dictated by its structure and by its ability to adopt different conformations, which in turn is encoded in the sequence. Experimental determination of high-resolution RNA structures is both laborious and difficult, and therefore the majority of known RNAs remain structurally uncharacterized. To address this problem, predictive computational methods were developed based on the accumulated knowledge of RNA structures determined so far, the physical basis of the RNA folding, and taking into account evolutionary considerations, such as conservation of functionally important motifs. However, all theoretical methods suffer from various limitations, and they are generally unable to accurately predict structures for RNA sequences longer than 100-nt residues unless aided by additional experimental data. In this article, we review experimental methods that can generate data usable by computational methods, as well as computational approaches for RNA structure prediction that can utilize data from experimental analyses. We outline methods and data types that can be potentially useful for RNA 3D structure modeling but are not commonly used by the existing software, suggesting directions for future development.
Collapse
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
Karade SS, Pandey S, Ansari A, Das S, Tripathi S, Arora A, Chopra S, Pratap JV, Dasgupta A. Rv3272 encodes a novel Family III CoA transferase that alters the cell wall lipid profile and protects mycobacteria from acidic and oxidative stress. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1867:317-330. [PMID: 30342240 DOI: 10.1016/j.bbapap.2018.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/01/2018] [Accepted: 10/16/2018] [Indexed: 11/26/2022]
Abstract
The availability of complete genome sequence of Mycobacterium tuberculosis has provided an important tool to understand the mycobacterial biology with respect to host-pathogen interaction, which is an unmet need of the hour owing to continuous increasing drug resistance. Hypothetical proteins are often an overlooked pool though half the genome encodes for such proteins of unknown function that could potentially play vital roles in mycobacterial biology. In this context, we report the structural and functional characterization of the hypothetical protein Rv3272. Sequence analysis classifies Rv3272 as a Family III CoA transferase with the classical two domain structure and conserved Aspartate residue (D175). The crystal structure of the wild type protein (2.2 Å) demonstrated the associated inter-locked dimer while that of the D175A mutant co-crystallized with octanoyl-CoA demonstrated relative movement between the two domains. Isothermal titration calorimetry studies indicate that Rv3272 binds to fatty acyl-CoAs of varying carbon chain lengths, with palmitoyl-CoA (C16:0) exhibiting maximum affinity. To determine the functional relevance of Rv3272 in mycobacterial biology, we ectopically expressed Rv3272 in M. smegmatis and assessed that its expression encodes significant alteration in cell surface with marked differences in triacylglycerol accumulation. Additionally, Rv3272 expression protects mycobacteria from acidic, oxidative and antibiotic stress under in vitro conditions. Taken together, these studies indicate a significant role for Rv3272 in host-pathogen interaction.
Collapse
Affiliation(s)
- Sharanbasappa Shrimant Karade
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Shilpika Pandey
- Microbiology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Ahmadullah Ansari
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Swetarka Das
- Microbiology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Sarita Tripathi
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Ashish Arora
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Sidharth Chopra
- Microbiology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - J Venkatesh Pratap
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India.
| | - Arunava Dasgupta
- Microbiology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India.
| |
Collapse
|
19
|
Hooy RM, Sohn J. The allosteric activation of cGAS underpins its dynamic signaling landscape. eLife 2018; 7:39984. [PMID: 30295605 PMCID: PMC6211831 DOI: 10.7554/elife.39984] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 10/05/2018] [Indexed: 12/22/2022] Open
Abstract
Cyclic G/AMP synthase (cGAS) initiates type-1 interferon responses against cytosolic double-stranded (ds)DNA, which range from antiviral gene expression to apoptosis. The mechanism by which cGAS shapes this diverse signaling landscape remains poorly defined. We find that substrate-binding and dsDNA length-dependent binding are coupled to the intrinsic dimerization equilibrium of cGAS, with its N-terminal domain potentiating dimerization. Notably, increasing the dimeric fraction by raising cGAS and substrate concentrations diminishes duplex length-dependent activation, but does not negate the requirement for dsDNA. These results demonstrate that reaction context dictates the duplex length dependence, reconciling competing claims on the role of dsDNA length in cGAS activation. Overall, our study reveals how ligand-mediated allostery positions cGAS in standby, ready to tune its signaling pathway in a switch-like fashion. The human immune system protects the body from various threats such as damaged cells or invading microbes. Many of these threats can move molecules of DNA, which are usually only found within a central compartment in the cell known as the nucleus, to the surrounding area, the cytoplasm. An enzyme called cGAS searches for DNA in the cytoplasm of human cells. When DNA binds to cGAS it activates the enzyme to convert certain molecules (referred to as ‘substrates’) into another molecule (the ‘signal’) that triggers various immune responses to protect the body against the threat. To produce the signal, two cGAS enzymes need to work together as a single unit called a dimer. The length of DNA molecules in the cytoplasm of cells can vary widely. It was initially thought that DNA molecules of any length binding to cGAS could activate the enzyme to a similar degree, but later studies demonstrated that this is not the case. However, it remains unclear how the length of the DNA could affect the activity of the enzyme, or why some of the earlier studies reported different findings. Hooy and Sohn used biochemical approaches to study the human cGAS enzyme. The experiments show that cGAS can form dimers even when no DNA is present. However, when DNA bound to cGAS, the enzyme was more likely to form dimers. Longer DNA molecules were better at promoting cGAS dimers to form than shorter DNA molecules. The binding of substrates to cGAS also made it more likely that the enzyme would form dimers. These findings suggest that inside cells cGAS is primed to trigger a switch-like response when it detects DNA in the cytoplasm. The work of Hooy and Sohn establishes a simple set of rules to predict how cGAS might respond in a given situation. Such information may aid in designing and tailoring efforts to regulate immune responses in human patients, and may provide insight into why the body responds to biological threats in different ways.
Collapse
Affiliation(s)
- Richard M Hooy
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Jungsan Sohn
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, United States
| |
Collapse
|
20
|
García-Estévez I, Ramos-Pineda AM, Escribano-Bailón MT. Interactions between wine phenolic compounds and human saliva in astringency perception. Food Funct 2018; 9:1294-1309. [PMID: 29417111 DOI: 10.1039/c7fo02030a] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Astringency is a complex perceptual phenomenon involving several sensations that are perceived simultaneously. The mechanism leading to these sensations has been thoroughly and controversially discussed in the literature and it is still not well understood since there are many contributing factors. Although we are still far from elucidating the mechanisms whereby astringency develops, the interaction between phenolic compounds and proteins (from saliva, oral mucosa or cells) seems to be most important. This review summarizes the recent trends in the protein-phenol interaction, focusing on the effect of the structure of the phenolic compound on the interaction with salivary proteins and on methodologies based on these interactions to determine astringency.
Collapse
Affiliation(s)
- Ignacio García-Estévez
- Grupo de Investigación en Polifenoles, Departament of Analytical Chemistry, Nutrition and Food Sciences, Faculty of Pharmacy, University of Salamanca, Campus Miguel de Unamuno s/n. E37007, Salamanca, Spain.
| | - Alba María Ramos-Pineda
- Grupo de Investigación en Polifenoles, Departament of Analytical Chemistry, Nutrition and Food Sciences, Faculty of Pharmacy, University of Salamanca, Campus Miguel de Unamuno s/n. E37007, Salamanca, Spain.
| | - María Teresa Escribano-Bailón
- Grupo de Investigación en Polifenoles, Departament of Analytical Chemistry, Nutrition and Food Sciences, Faculty of Pharmacy, University of Salamanca, Campus Miguel de Unamuno s/n. E37007, Salamanca, Spain.
| |
Collapse
|
21
|
Lehmann LC, Hewitt G, Aibara S, Leitner A, Marklund E, Maslen SL, Maturi V, Chen Y, van der Spoel D, Skehel JM, Moustakas A, Boulton SJ, Deindl S. Mechanistic Insights into Autoinhibition of the Oncogenic Chromatin Remodeler ALC1. Mol Cell 2017; 68:847-859.e7. [PMID: 29220652 PMCID: PMC5745148 DOI: 10.1016/j.molcel.2017.10.017] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 08/16/2017] [Accepted: 10/17/2017] [Indexed: 02/07/2023]
Abstract
Human ALC1 is an oncogene-encoded chromatin-remodeling enzyme required for DNA repair that possesses a poly(ADP-ribose) (PAR)-binding macro domain. Its engagement with PARylated PARP1 activates ALC1 at sites of DNA damage, but the underlying mechanism remains unclear. Here, we establish a dual role for the macro domain in autoinhibition of ALC1 ATPase activity and coupling to nucleosome mobilization. In the absence of DNA damage, an inactive conformation of the ATPase is maintained by juxtaposition of the macro domain against predominantly the C-terminal ATPase lobe through conserved electrostatic interactions. Mutations within this interface displace the macro domain, constitutively activate the ALC1 ATPase independent of PARylated PARP1, and alter the dynamics of ALC1 recruitment at DNA damage sites. Upon DNA damage, binding of PARylated PARP1 by the macro domain induces a conformational change that relieves autoinhibitory interactions with the ATPase motor, which selectively activates ALC1 remodeling upon recruitment to sites of DNA damage.
Collapse
Affiliation(s)
- Laura C Lehmann
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, 75124 Uppsala, Sweden
| | - Graeme Hewitt
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Shintaro Aibara
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165 Solna, Sweden
| | - Alexander Leitner
- Department of Biology, Institute of Molecular Systems Biology, Swiss Federal Institute of Technology, 8093 Zürich, Switzerland
| | - Emil Marklund
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, 75124 Uppsala, Sweden
| | - Sarah L Maslen
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Varun Maturi
- Department of Medical Biochemistry and Microbiology, and Ludwig Institute for Cancer Research, Science for Life Laboratory, Uppsala University, 75123 Uppsala, Sweden
| | - Yang Chen
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, 75124 Uppsala, Sweden
| | - David van der Spoel
- Department of Cell and Molecular Biology, Computational Biology and Bioinformatics, Uppsala University, 75124 Uppsala, Sweden
| | - J Mark Skehel
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Aristidis Moustakas
- Department of Medical Biochemistry and Microbiology, and Ludwig Institute for Cancer Research, Science for Life Laboratory, Uppsala University, 75123 Uppsala, Sweden
| | - Simon J Boulton
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
| | - Sebastian Deindl
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, 75124 Uppsala, Sweden.
| |
Collapse
|
22
|
Mitić Ž, Stolić A, Stojanović S, Najman S, Ignjatović N, Nikolić G, Trajanović M. Instrumental methods and techniques for structural and physicochemical characterization of biomaterials and bone tissue: A review. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017. [DOI: 10.1016/j.msec.2017.05.127] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
23
|
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: 384] [Impact Index Per Article: 54.9] [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.
Collapse
|
24
|
Sønderby P, Rinnan Å, Madsen JJ, Harris P, Bukrinski JT, Peters GHJ. Small-Angle X-ray Scattering Data in Combination with RosettaDock Improves the Docking Energy Landscape. J Chem Inf Model 2017; 57:2463-2475. [DOI: 10.1021/acs.jcim.6b00789] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Pernille Sønderby
- Department
of Chemistry, Technical University of Denmark, DK-2800 Kongens
Lyngby, Denmark
| | - Åsmund Rinnan
- Department
of Food Science, Faculty of Science, University of Copenhagen, DK-1958 Frederiksberg C, Denmark
| | - Jesper J. Madsen
- Department
of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Pernille Harris
- Department
of Chemistry, Technical University of Denmark, DK-2800 Kongens
Lyngby, Denmark
| | | | - Günther H. J. Peters
- Department
of Chemistry, Technical University of Denmark, DK-2800 Kongens
Lyngby, Denmark
| |
Collapse
|
25
|
Mizrachi D, Robinson MP, Ren G, Ke N, Berkmen M, DeLisa MP. A water-soluble DsbB variant that catalyzes disulfide-bond formation in vivo. Nat Chem Biol 2017; 13:1022-1028. [PMID: 28628094 PMCID: PMC5562517 DOI: 10.1038/nchembio.2409] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 03/30/2017] [Indexed: 12/17/2022]
Abstract
Escherichia coli DsbB is a transmembrane enzyme that catalyzes the reoxidation of the periplasmic oxidase DsbA by ubiquinone. Here, we sought to convert membrane-bound DsbB into a water-soluble biocatalyst by leveraging a previously described method for in vivo solubilization of integral membrane proteins (IMPs). When solubilized DsbB variants were coexpressed with an export-defective copy of DsbA in the cytoplasm of wild-type E. coli cells, artificial oxidation pathways were created that efficiently catalyzed de novo disulfide-bond formation in a range of substrate proteins, in a manner dependent on both DsbA and quinone. Hence, DsbB solubilization was achieved with preservation of both catalytic activity and substrate specificity. Moreover, given the generality of the solubilization technique, the results presented here should pave the way to unlocking the biocatalytic potential of other membrane-bound enzymes whose utility has been limited by poor stability of IMPs outside of their native lipid-bilayer context.
Collapse
Affiliation(s)
- Dario Mizrachi
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853 USA
| | - Michael-Paul Robinson
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853 USA
| | - Guoping Ren
- New England Biolabs, 240 County Rd, Ipswich, MA, 01938, USA
| | - Na Ke
- New England Biolabs, 240 County Rd, Ipswich, MA, 01938, USA
| | - Mehmet Berkmen
- New England Biolabs, 240 County Rd, Ipswich, MA, 01938, USA
| | - Matthew P. DeLisa
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853 USA
| |
Collapse
|
26
|
Tuukkanen AT, Spilotros A, Svergun DI. Progress in small-angle scattering from biological solutions at high-brilliance synchrotrons. IUCRJ 2017; 4:518-528. [PMID: 28989709 PMCID: PMC5619845 DOI: 10.1107/s2052252517008740] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/12/2017] [Indexed: 05/26/2023]
Abstract
Small-angle X-ray scattering (SAXS) is an established technique that provides low-resolution structural information on macromolecular solutions. Recent decades have witnessed significant progress in both experimental facilities and in novel data-analysis approaches, making SAXS a mainstream method for structural biology. The technique is routinely applied to directly reconstruct low-resolution shapes of proteins and to generate atomistic models of macromolecular assemblies using hybrid approaches. Very importantly, SAXS is capable of yielding structural information on systems with size and conformational polydispersity, including highly flexible objects. In addition, utilizing high-flux synchrotron facilities, time-resolved SAXS allows analysis of kinetic processes over time ranges from microseconds to hours. Dedicated bioSAXS beamlines now offer fully automated data-collection and analysis pipelines, where analysis and modelling is conducted on the fly. This enables SAXS to be employed as a high-throughput method to rapidly screen various sample conditions and additives. The growing SAXS user community is supported by developments in data and model archiving and quality criteria. This review illustrates the latest developments in SAXS, in particular highlighting time-resolved applications aimed at flexible and evolving systems.
Collapse
Affiliation(s)
- Anne T. Tuukkanen
- European Molecular Biology Laboratory, EMBL Hamburg c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Alessandro Spilotros
- European Molecular Biology Laboratory, EMBL Hamburg c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory, EMBL Hamburg c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| |
Collapse
|
27
|
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.
Collapse
|
28
|
Verma R, Mitchell-Koch K. In Silico Studies of Small Molecule Interactions with Enzymes Reveal Aspects of Catalytic Function. Catalysts 2017; 7:212. [PMID: 30464857 PMCID: PMC6241538 DOI: 10.3390/catal7070212] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Small molecules, such as solvent, substrate, and cofactor molecules, are key players in enzyme catalysis. Computational methods are powerful tools for exploring the dynamics and thermodynamics of these small molecules as they participate in or contribute to enzymatic processes. In-depth knowledge of how small molecule interactions and dynamics influence protein conformational dynamics and function is critical for progress in the field of enzyme catalysis. Although numerous computational studies have focused on enzyme-substrate complexes to gain insight into catalytic mechanisms, transition states and reaction rates, the dynamics of solvents, substrates, and cofactors are generally less well studied. Also, solvent dynamics within the biomolecular solvation layer play an important part in enzyme catalysis, but a full understanding of its role is hampered by its complexity. Moreover, passive substrate transport has been identified in certain enzymes, and the underlying principles of molecular recognition are an area of active investigation. Enzymes are highly dynamic entities that undergo different conformational changes, which range from side chain rearrangement of a residue to larger-scale conformational dynamics involving domains. These events may happen nearby or far away from the catalytic site, and may occur on different time scales, yet many are related to biological and catalytic function. Computational studies, primarily molecular dynamics (MD) simulations, provide atomistic-level insight and site-specific information on small molecule interactions, and their role in conformational pre-reorganization and dynamics in enzyme catalysis. The review is focused on MD simulation studies of small molecule interactions and dynamics to characterize and comprehend protein dynamics and function in catalyzed reactions. Experimental and theoretical methods available to complement and expand insight from MD simulations are discussed briefly.
Collapse
Affiliation(s)
- Rajni Verma
- Department of Chemistry, McKinley Hall, Wichita State University, 1845 Fairmount, Wichita, KS 67260-0051, USA
| | - Katie Mitchell-Koch
- Department of Chemistry, McKinley Hall, Wichita State University, 1845 Fairmount, Wichita, KS 67260-0051, USA
| |
Collapse
|
29
|
Manaia EB, Abuçafy MP, Chiari-Andréo BG, Silva BL, Oshiro Junior JA, Chiavacci LA. Physicochemical characterization of drug nanocarriers. Int J Nanomedicine 2017; 12:4991-5011. [PMID: 28761340 PMCID: PMC5516877 DOI: 10.2147/ijn.s133832] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Pharmaceutical design has enabled important advances in the prevention, treatment, and diagnosis of diseases. The use of nanotechnology to optimize the delivery of drugs and diagnostic molecules is increasingly receiving attention due to the enhanced efficiency provided by these systems. Understanding the structures of nanocarriers is crucial in elucidating their physical and chemical properties, which greatly influence their behavior in the body at both the molecular and systemic levels. This review was conducted to describe the principles and characteristics of techniques commonly used to elucidate the structures of nanocarriers, with consideration of their size, morphology, surface charge, porosity, crystalline arrangement, and phase. These techniques include X-ray diffraction, small-angle X-ray scattering, dynamic light scattering, zeta potential, polarized light microscopy, transmission electron microscopy, scanning electron microcopy, and porosimetry. Moreover, we describe some of the commonly used nanocarriers (liquid crystals, metal-organic frameworks, silica nanospheres, liposomes, solid lipid nanoparticles, and micelles) and the main aspects of their structures.
Collapse
Affiliation(s)
- Eloísa Berbel Manaia
- Department of Drugs and Medicines, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - Marina Paiva Abuçafy
- Department of Drugs and Medicines, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - Bruna Galdorfini Chiari-Andréo
- Department of Drugs and Medicines, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, SP, Brazil
- Department of Biological and Health Sciences, Centro Universitário de Araraquara, UNIARA, Araraquara, SP, Brazil
| | - Bruna Lallo Silva
- Department of Drugs and Medicines, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - João Augusto Oshiro Junior
- Department of Drugs and Medicines, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - Leila Aparecida Chiavacci
- Department of Drugs and Medicines, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, SP, Brazil
| |
Collapse
|
30
|
Brognaro H, Almeida VM, de Araujo EA, Piyadov V, Santos MAM, Marana SR, Polikarpov I. Biochemical Characterization and Low-Resolution SAXS Molecular Envelope of GH1 β-Glycosidase from Saccharophagus degradans. Mol Biotechnol 2017; 58:777-788. [PMID: 27670285 DOI: 10.1007/s12033-016-9977-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The marine bacteria Saccharophagus degradans (also known as Microbulbifer degradans), are rod-shaped and gram-negative motile γ-proteobacteria, capable of both degrading a variety of complex polysaccharides and fermenting monosaccharides into ethanol. In order to obtain insights into structure-function relationships of the enzymes, involved in these biochemical processes, we characterized a S. degradans β-glycosidase from glycoside hydrolase family 1 (SdBgl1B). SdBgl1B has the optimum pH of 6.0 and a melting temperature T m of approximately 50 °C. The enzyme has high specificity toward short D-glucose saccharides with β-linkages with the following preferences β-1,3 > β-1,4 ≫ β-1,6. The enzyme kinetic parameters, obtained using artificial substrates p-β-NPGlu and p-β-NPFuc and also the disaccharides cellobiose, gentiobiose and laminaribiose, revealed SdBgl1B preference for p-β-NPGlu and laminaribiose, which indicates its affinity for glucose and also preference for β-1,3 linkages. To better understand structural basis of the enzyme activity its 3D model was built and analysed. The 3D model fits well into the experimentally retrieved low-resolution SAXS-based envelope of the enzyme, confirming monomeric state of SdBgl1B in solution.
Collapse
Affiliation(s)
- Hevila Brognaro
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São Carlense 400, São Carlos, SP, 13566-590, Brazil
| | - Vitor Medeiros Almeida
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 748, Bloco 10, Sala 1054, São Paulo, SP, 05508-900, Brazil
| | - Evandro Ares de Araujo
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São Carlense 400, São Carlos, SP, 13566-590, Brazil
| | - Vasily Piyadov
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São Carlense 400, São Carlos, SP, 13566-590, Brazil
| | - Maria Auxiliadora Morim Santos
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São Carlense 400, São Carlos, SP, 13566-590, Brazil
| | - Sandro Roberto Marana
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 748, Bloco 10, Sala 1054, São Paulo, SP, 05508-900, Brazil
| | - Igor Polikarpov
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São Carlense 400, São Carlos, SP, 13566-590, Brazil.
| |
Collapse
|
31
|
Structural studies of RNA-protein complexes: A hybrid approach involving hydrodynamics, scattering, and computational methods. Methods 2016; 118-119:146-162. [PMID: 27939506 DOI: 10.1016/j.ymeth.2016.12.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/01/2016] [Accepted: 12/05/2016] [Indexed: 01/01/2023] Open
Abstract
The diverse functional cellular roles played by ribonucleic acids (RNA) have emphasized the need to develop rapid and accurate methodologies to elucidate the relationship between the structure and function of RNA. Structural biology tools such as X-ray crystallography and Nuclear Magnetic Resonance are highly useful methods to obtain atomic-level resolution models of macromolecules. However, both methods have sample, time, and technical limitations that prevent their application to a number of macromolecules of interest. An emerging alternative to high-resolution structural techniques is to employ a hybrid approach that combines low-resolution shape information about macromolecules and their complexes from experimental hydrodynamic (e.g. analytical ultracentrifugation) and solution scattering measurements (e.g., solution X-ray or neutron scattering), with computational modeling to obtain atomic-level models. While promising, scattering methods rely on aggregation-free, monodispersed preparations and therefore the careful development of a quality control pipeline is fundamental to an unbiased and reliable structural determination. This review article describes hydrodynamic techniques that are highly valuable for homogeneity studies, scattering techniques useful to study the low-resolution shape, and strategies for computational modeling to obtain high-resolution 3D structural models of RNAs, proteins, and RNA-protein complexes.
Collapse
|
32
|
Yadav DK, Lukavsky PJ. NMR solution structure determination of large RNA-protein complexes. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2016; 97:57-81. [PMID: 27888840 DOI: 10.1016/j.pnmrs.2016.10.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 10/04/2016] [Accepted: 10/04/2016] [Indexed: 06/06/2023]
Abstract
Structure determination of RNA-protein complexes is essential for our understanding of the multiple layers of RNA-mediated posttranscriptional regulation of gene expression. Over the past 20years, NMR spectroscopy became a key tool for structural studies of RNA-protein interactions. Here, we review the progress being made in NMR structure determination of large ribonucleoprotein assemblies. We discuss approaches for the design of RNA-protein complexes for NMR structural studies, established and emerging isotope and segmental labeling schemes suitable for large RNPs and how to gain distance restraints from NOEs, PREs and EPR and orientational information from RDCs and SAXS/SANS in such systems. The new combination of NMR measurements with MD simulations and its potential will also be discussed. Application and combination of these various methods for structure determination of large RNPs will be illustrated with three large RNA-protein complexes (>40kDa) and other interesting complexes determined in the past six and a half years.
Collapse
Affiliation(s)
- Deepak Kumar Yadav
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, 62500 Brno, Czech Republic
| | - Peter J Lukavsky
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, 62500 Brno, Czech Republic.
| |
Collapse
|
33
|
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.
Collapse
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
| |
Collapse
|
34
|
Strulovich R, Tobelaim WS, Attali B, Hirsch JA. Structural Insights into the M-Channel Proximal C-Terminus/Calmodulin Complex. Biochemistry 2016; 55:5353-65. [PMID: 27564677 DOI: 10.1021/acs.biochem.6b00477] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Kv7 (KCNQ) channel family, comprising voltage-gated potassium channels, plays major roles in fine-tuning cellular excitability by reducing firing frequency and controlling repolarization. Kv7 channels have a unique intracellular C-terminal (CT) domain bound constitutively by calmodulin (CaM). This domain plays key functions in channel tetramerization, trafficking, and gating. CaM binds to the proximal CT, comprising helices A and B. Kv7.2 and Kv7.3 are expressed in neural tissues. Together, they form the heterotetrameric M channel. We characterized Kv7.2, Kv7.3, and chimeric Kv7.3 helix A-Kv7.2 helix B (Q3A-Q2B) proximal CT/CaM complexes by solution methods at various Ca(2+)concentrations and determined them all to have a 1:1 stoichiometry. We then determined the crystal structure of the Q3A-Q2B/CaM complex at high Ca(2+) concentration to 2.0 Å resolution. CaM hugs the antiparallel coiled coil of helices A and B, braced together by an additional helix. The structure displays a hybrid apo-Ca(2+) CaM conformation even though four Ca(2+) ions are bound. Our results pinpoint unique interactions enabling the possible intersubunit pairing of Kv7.3 helix A and Kv7.2 helix B while underlining the potential importance of Kv7.3 helix A's role in stabilizing channel oligomerization. Also, the structure can be used to rationalize various channelopathic mutants. Functional testing of the chimeric channel found it to have a voltage-dependence similar to the M channel, thereby demonstrating helix A's importance in imparting gating properties.
Collapse
Affiliation(s)
- Roi Strulovich
- Department of Biochemistry and Molecular Biology, Institute of Structural Biology, George S. Wise Faculty of Life Sciences, ‡Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and §Sagol School of Neuroscience, Tel Aviv University , Ramat Aviv 69978, Israel
| | - William Sam Tobelaim
- Department of Biochemistry and Molecular Biology, Institute of Structural Biology, George S. Wise Faculty of Life Sciences, ‡Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and §Sagol School of Neuroscience, Tel Aviv University , Ramat Aviv 69978, Israel
| | - Bernard Attali
- Department of Biochemistry and Molecular Biology, Institute of Structural Biology, George S. Wise Faculty of Life Sciences, ‡Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and §Sagol School of Neuroscience, Tel Aviv University , Ramat Aviv 69978, Israel
| | - Joel A Hirsch
- Department of Biochemistry and Molecular Biology, Institute of Structural Biology, George S. Wise Faculty of Life Sciences, ‡Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and §Sagol School of Neuroscience, Tel Aviv University , Ramat Aviv 69978, Israel
| |
Collapse
|
35
|
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.
Collapse
Affiliation(s)
| | | | - Federico Forneris
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of PaviaPavia, Italy
| |
Collapse
|
36
|
Schindler C, de Vries S, Sasse A, Zacharias M. SAXS Data Alone can Generate High-Quality Models of Protein-Protein Complexes. Structure 2016; 24:1387-1397. [DOI: 10.1016/j.str.2016.06.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 06/08/2016] [Accepted: 06/08/2016] [Indexed: 11/29/2022]
|
37
|
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.
Collapse
|
38
|
Bhagawati M, Rubashkin MG, Lee JP, Ananthanarayanan B, Weaver VM, Kumar S. Site-Specific Modulation of Charge Controls the Structure and Stimulus Responsiveness of Intrinsically Disordered Peptide Brushes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:5990-5996. [PMID: 27203736 PMCID: PMC5343758 DOI: 10.1021/acs.langmuir.6b01099] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Intrinsically disordered proteins (IDPs) are an important and emerging class of materials for tailoring biointerfaces. While the importance of chain charge and resultant electrostatic interactions in controlling conformational properties of IDPs is beginning to be explored through in silico approaches, there is a dearth of experimental studies motivated toward a systematic study of these effects. In an effort to explore this relationship, we measured the conformations of two peptides derived from the intrinsically disordered neurofilament (NF) side arm domain: one depicting the wild-type sequence with four lysine-serine-proline repeats (KSP peptide) and another in which the serine residues were replaced with aspartates (KDP peptide), a strategy sometimes used to mimic phosphorylation. Using a variety of biophysical measurements including a novel application of scanning angle interference microscopy, we demonstrate that the KDP peptide assumes comparatively more expanded conformations in solution and forms significantly thicker brushes when immobilized on planar surfaces at high densities. In both settings, the peptides respond to changes in ambient ionic strength, with each peptide showing distinct stimulus-responsive characteristics. While the KDP peptide undergoes compaction with increasing ionic strength as would be expected for a polyampholyte, the KSP peptide shows biphasic behavior, with an initial compaction followed by an expanded state at a higher ionic strength. Together these results support the notion that modulation of charge on IDPs can regulate conformational and interfacial properties.
Collapse
Affiliation(s)
- Maniraj Bhagawati
- Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Matt G. Rubashkin
- Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, San Francisco, California 94143, United States
- UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Jessica P. Lee
- Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | | | - Valerie M. Weaver
- Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, San Francisco, California 94143, United States
- UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Sanjay Kumar
- Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
- UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| |
Collapse
|
39
|
Abstract
The main food quality traits of interest using non-invasive sensing techniques are sensory characteristics, chemical composition, physicochemical properties, health-protecting properties, nutritional characteristics and safety. A wide range of non-invasive sensing techniques, from optical, acoustical, electrical, to nuclear magnetic, X-ray, biosensor, microwave and terahertz, are organized according to physical principle.
Collapse
Affiliation(s)
- Zou Xiaobo
- Agricultural Product Processing and Storage Lab
- School of Food and Biological Engineering
- Key Laboratory of Modern Agriculture Equipment and Technology
- Jiangsu University
- Zhenjiang
| | - Huang Xiaowei
- Agricultural Product Processing and Storage Lab
- School of Food and Biological Engineering
- Key Laboratory of Modern Agriculture Equipment and Technology
- Jiangsu University
- Zhenjiang
| | - Malcolm Povey
- School of Food Science and Nutrition
- the University of Leeds
- Leeds LS2 9JT
- UK
| |
Collapse
|
40
|
Schelpe J, Monté D, Dewitte F, Sixma TK, Rucktooa P. Structure of UBE2Z Enzyme Provides Functional Insight into Specificity in the FAT10 Protein Conjugation Machinery. J Biol Chem 2015; 291:630-9. [PMID: 26555268 PMCID: PMC4705383 DOI: 10.1074/jbc.m115.671545] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Indexed: 12/05/2022] Open
Abstract
FAT10 conjugation, a post-translational modification analogous to ubiquitination, specifically requires UBA6 and UBE2Z as its activating (E1) and conjugating (E2) enzymes. Interestingly, these enzymes can also function in ubiquitination. We have determined the crystal structure of UBE2Z and report how the different domains of this E2 enzyme are organized. We further combine our structural data with mutational analyses to understand how specificity is achieved in the FAT10 conjugation pathway. We show that specificity toward UBA6 and UBE2Z lies within the C-terminal CYCI tetrapeptide in FAT10. We also demonstrate that this motif slows down transfer rates for FAT10 from UBA6 onto UBE2Z.
Collapse
Affiliation(s)
- Julien Schelpe
- From the UMR8576 CNRS-Université de Lille, 50 Avenue de Halley, 59658 Villeneuve d'Ascq, France and
| | - Didier Monté
- From the UMR8576 CNRS-Université de Lille, 50 Avenue de Halley, 59658 Villeneuve d'Ascq, France and
| | - Frédérique Dewitte
- From the UMR8576 CNRS-Université de Lille, 50 Avenue de Halley, 59658 Villeneuve d'Ascq, France and
| | - Titia K Sixma
- Division of Biochemistry and Centre for Biomedical Genetics, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Prakash Rucktooa
- From the UMR8576 CNRS-Université de Lille, 50 Avenue de Halley, 59658 Villeneuve d'Ascq, France and Division of Biochemistry and Centre for Biomedical Genetics, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| |
Collapse
|
41
|
Onuk AE, Akcakaya M, Bardhan JP, Erdogmus D, Brooks DH, Makowski L. Constrained Maximum Likelihood Estimation of Relative Abundances of Protein Conformation in a Heterogeneous Mixture from Small Angle X-Ray Scattering Intensity Measurements. IEEE TRANSACTIONS ON SIGNAL PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2015; 63:5383-5394. [PMID: 26924916 PMCID: PMC4767180 DOI: 10.1109/tsp.2015.2455515] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this paper, we describe a model for maximum likelihood estimation (MLE) of the relative abundances of different conformations of a protein in a heterogeneous mixture from small angle X-ray scattering (SAXS) intensities. To consider cases where the solution includes intermediate or unknown conformations, we develop a subset selection method based on k-means clustering and the Cramér-Rao bound on the mixture coefficient estimation error to find a sparse basis set that represents the space spanned by the measured SAXS intensities of the known conformations of a protein. Then, using the selected basis set and the assumptions on the model for the intensity measurements, we show that the MLE model can be expressed as a constrained convex optimization problem. Employing the adenylate kinase (ADK) protein and its known conformations as an example, and using Monte Carlo simulations, we demonstrate the performance of the proposed estimation scheme. Here, although we use 45 crystallographically determined experimental structures and we could generate many more using, for instance, molecular dynamics calculations, the clustering technique indicates that the data cannot support the determination of relative abundances for more than 5 conformations. The estimation of this maximum number of conformations is intrinsic to the methodology we have used here.
Collapse
Affiliation(s)
- A Emre Onuk
- Electrical and Computer Engineering Department, Northeastern University, Boston, MA
| | - Murat Akcakaya
- Electrical and Computer Engineering Department, University of Pittsburgh, Pittsburgh, PA
| | - Jaydeep P Bardhan
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA
| | - Deniz Erdogmus
- Electrical and Computer Engineering Department, Northeastern University, Boston, MA
| | - Dana H Brooks
- Electrical and Computer Engineering Department, Northeastern University, Boston, MA
| | - Lee Makowski
- Bioengineering Department, Northeastern University, Boston, MA; Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA
| |
Collapse
|
42
|
Yadav RP, Majumder A, Gakhar L, Artemyev NO. Extended conformation of the proline-rich domain of human aryl hydrocarbon receptor-interacting protein-like 1: implications for retina disease. J Neurochem 2015; 135:165-75. [PMID: 26139345 DOI: 10.1111/jnc.13223] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 05/29/2015] [Accepted: 06/25/2015] [Indexed: 12/18/2022]
Abstract
Mutations in the primate-specific proline-rich domain (PRD) of aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) are thought to cause Leber congenital amaurosis or dominant cone-rod dystrophy. The role of PRD and the mechanisms of PRD mutations are poorly understood. Here, we have examined properties of hAIPL1 and effects of the PRD mutations on protein structure and function. Solution structures of hAIPL1, hAIPL11-316 with PRD truncation, and the P351Δ12 and P376S mutants were examined by small angle X-ray scattering. Our analysis suggests that PRD assumes an extended conformation and does not interact with the FK506-binding and tetratricopeptide domains. The PRD truncation, but not PRD mutations, reduced the molecule's radius of gyration and maximum dimension. We demonstrate that hAIPL1 is a monomeric protein, and its secondary structure and stability are not affected by the PRD mutations. PRD itself is an extended monomeric random coil. The PRD mutations caused little or no changes in hAIPL1 binding to known partners, phosphodiesterase-6A and HSP90. We also identified the γ-subunit of phosphodiesterase-6 as a novel partner of hAIPL1 and hypothesize that this interaction is altered by P351Δ12. Our results highlight the complexity of mechanisms of PRD mutations in disease and the possibility that certain mutations are benign variants. Mutations in the proline-rich domain (PRD) of human AIPL1 cause severe retinal diseases, yet the role of PRD and the mechanisms of PRD mutations are unknown. Here, we describe a SAXS-derived solution structure of AIPL1 and functional properties of disease-linked AIPL1-PRD mutants. This structure and functional analyses provide a framework for understanding the mechanisms of PRD in disease.
Collapse
Affiliation(s)
- Ravi P Yadav
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA
| | - Anurima Majumder
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA
| | - Lokesh Gakhar
- Department of Biochemistry, University of Iowa, Iowa City, Iowa, USA.,Protein Crystallography Facility, University of Iowa, Iowa City, Iowa, USA
| | - Nikolai O Artemyev
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA.,Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, USA
| |
Collapse
|
43
|
Cell-free expression of functional receptor tyrosine kinases. Sci Rep 2015; 5:12896. [PMID: 26274523 PMCID: PMC4929682 DOI: 10.1038/srep12896] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 05/28/2015] [Indexed: 12/22/2022] Open
Abstract
Receptor tyrosine kinases (RTKs) play critical roles in physiological and pathological processes, and are important anticancer drug targets. In vitro mechanistic and drug discovery studies of full-length RTKs require protein that is both fully functional and free from contaminating proteins. Here we describe a rapid cell-free and detergent-free co-translation method for producing full-length and functional ERBB2 and EGFR receptor tyrosine kinases supported by water-soluble apolipoprotein A-I based nanolipoprotein particles.
Collapse
|
44
|
Petukhov AV, Meijer JM, Vroege GJ. Particle shape effects in colloidal crystals and colloidal liquid crystals: Small-angle X-ray scattering studies with microradian resolution. Curr Opin Colloid Interface Sci 2015. [DOI: 10.1016/j.cocis.2015.09.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
45
|
Malaby AW, Chakravarthy S, Irving TC, Kathuria SV, Bilsel O, Lambright DG. Methods for analysis of size-exclusion chromatography-small-angle X-ray scattering and reconstruction of protein scattering. J Appl Crystallogr 2015; 48:1102-1113. [PMID: 26306089 DOI: 10.1107/s1600576715010420] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 05/31/2015] [Indexed: 11/10/2022] Open
Abstract
Size-exclusion chromatography in line with small-angle X-ray scattering (SEC-SAXS) has emerged as an important method for investigation of heterogeneous and self-associating systems, but presents specific challenges for data processing including buffer subtraction and analysis of overlapping peaks. This paper presents novel methods based on singular value decomposition (SVD) and Guinier-optimized linear combination (LC) to facilitate analysis of SEC-SAXS data sets and high-quality reconstruction of protein scattering directly from peak regions. It is shown that Guinier-optimized buffer subtraction can reduce common subtraction artifacts and that Guinier-optimized linear combination of significant SVD basis components improves signal-to-noise and allows reconstruction of protein scattering, even in the absence of matching buffer regions. In test cases with conventional SAXS data sets for cytochrome c and SEC-SAXS data sets for the small GTPase Arf6 and the Arf GTPase exchange factors Grp1 and cytohesin-1, SVD-LC consistently provided higher quality reconstruction of protein scattering than either direct or Guinier-optimized buffer subtraction. These methods have been implemented in the context of a Python-extensible Mac OS X application known as Data Evaluation and Likelihood Analysis (DELA), which provides convenient tools for data-set selection, beam intensity normalization, SVD, and other relevant processing and analytical procedures, as well as automated Python scripts for common SAXS analyses and Guinier-optimized reconstruction of protein scattering.
Collapse
Affiliation(s)
- Andrew W Malaby
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA ; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Srinivas Chakravarthy
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Chemical and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Thomas C Irving
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Chemical and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Sagar V Kathuria
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Osman Bilsel
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - David G Lambright
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA ; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| |
Collapse
|
46
|
Karlsen ML, Thorsen TS, Johner N, Ammendrup-Johnsen I, Erlendsson S, Tian X, Simonsen JB, Høiberg-Nielsen R, Christensen NM, Khelashvili G, Streicher W, Teilum K, Vestergaard B, Weinstein H, Gether U, Arleth L, Madsen KL. Structure of Dimeric and Tetrameric Complexes of the BAR Domain Protein PICK1 Determined by Small-Angle X-Ray Scattering. Structure 2015; 23:1258-1270. [PMID: 26073603 DOI: 10.1016/j.str.2015.04.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/20/2015] [Accepted: 04/23/2015] [Indexed: 11/15/2022]
Abstract
PICK1 is a neuronal scaffolding protein containing a PDZ domain and an auto-inhibited BAR domain. BAR domains are membrane-sculpting protein modules generating membrane curvature and promoting membrane fission. Previous data suggest that BAR domains are organized in lattice-like arrangements when stabilizing membranes but little is known about structural organization of BAR domains in solution. Through a small-angle X-ray scattering (SAXS) analysis, we determine the structure of dimeric and tetrameric complexes of PICK1 in solution. SAXS and biochemical data reveal a strong propensity of PICK1 to form higher-order structures, and SAXS analysis suggests an offset, parallel mode of BAR-BAR oligomerization. Furthermore, unlike accessory domains in other BAR domain proteins, the positioning of the PDZ domains is flexible, enabling PICK1 to perform long-range, dynamic scaffolding of membrane-associated proteins. Together with functional data, these structural findings are compatible with a model in which oligomerization governs auto-inhibition of BAR domain function.
Collapse
Affiliation(s)
- Morten L Karlsen
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Thor S Thorsen
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Niklaus Johner
- Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, Room E-509, 1300 York Avenue, 10065, New York City, NY, USA
| | - Ina Ammendrup-Johnsen
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Simon Erlendsson
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark.,Structural Biology and NMR Laboratory, Department of Biology, Faculty of Science, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
| | - Xinsheng Tian
- Biostructural Research, Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen Ø, Denmark
| | - Jens B Simonsen
- Structural Biophysics, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Rasmus Høiberg-Nielsen
- Structural Biophysics, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Nikolaj M Christensen
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - George Khelashvili
- Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, Room E-509, 1300 York Avenue, 10065, New York City, NY, USA
| | - Werner Streicher
- NNF Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
| | - Kaare Teilum
- Structural Biology and NMR Laboratory, Department of Biology, Faculty of Science, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
| | - Bente Vestergaard
- Biostructural Research, Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen Ø, Denmark
| | - Harel Weinstein
- Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, Room E-509, 1300 York Avenue, 10065, New York City, NY, USA
| | - Ulrik Gether
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Lise Arleth
- Structural Biophysics, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Kenneth L Madsen
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark
| |
Collapse
|
47
|
Abstract
Plectin and BPAG1e belong to the plakin family of high-molecular-weight proteins that interconnect the cytoskeletal systems and anchor them to junctional complexes. Plectin and BPAG1e are prototypical plakins with a similar tripartite modular structure. The N- and C-terminal regions are built of multiple discrete structural domains, while the central rod domain mediates dimerization by coiled-coil interactions. Owing to the mosaic organization of plakins, the structure of their constituent individual domains or small multi-domain segments can be analyzed isolated. Yet, understanding the integrated function of large regions, oligomers, and heterocomplexes of plakins is difficult due to the large and segmented structure. Here, we describe methods for the production of plectin and BPAG1e samples suitable for structural and biophysical analysis. In addition, we discuss the combination of hybrid methods that yield information at several resolution levels to study the complex, multi-domain, and flexible structure of plakins.
Collapse
|
48
|
Hynson RMG, Duff AP, Kirby N, Mudie S, Lee LK. Differential ultracentrifugation coupled to small-angle X-ray scattering on macromolecular complexes. J Appl Crystallogr 2015. [DOI: 10.1107/s1600576715005051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Small-angle X-ray scattering (SAXS) can provide accurate structural information and low-resolution shapes of macromolecules in solution. The technique is particularly amenable to large protein assemblies, which produce a strong scattering signal. Hence, SAXS can be a powerful tool to elucidate quaternary structure, especially when used in combination with high-resolution structural techniques such as X-ray crystallography and NMR. Sample requirements for SAXS experiments are stringent and only monodispersed samples can be satisfactorily analysed. Often, it is not possible to obtain a stable monodispersed sample of the protein of interest, in particular for multi-subunit protein complexes. In these circumstances, when the complex is less than approximately 1 MDa, size exclusion chromatography (SEC) coupled with SAXS (SEC-SAXS) can facilitate the separation of monodispersed protein from a polydispersed sample for a sufficient amount of time to collect useful SAXS data. However, many very large multi-subunit macromolecular assemblies have not been successfully purified with SEC, and hence despite being well suited to SAXS there is often no way to produce sample of sufficient quality. Rather than SEC, differential ultracentrifugation (DU) is the method of choice for the final step in the purification of large macromolecular protein complexes. Here, a new method is described for collecting SAXS data on samples directly from the fractionated elution of ultracentrifuge tubes after DU. It is demonstrated using apoferritin as a model protein that, like SEC-SAXS, DU-coupled SAXS can facilitate simultaneous purification and data collection. It is envisaged that this new method will enable high-quality SAXS data to be collected on a host of large macromolecular protein complex assemblies for the first time.
Collapse
|
49
|
Mizrachi D, Chen Y, Liu J, Peng HM, Ke A, Pollack L, Turner RJ, Auchus RJ, DeLisa MP. Making water-soluble integral membrane proteins in vivo using an amphipathic protein fusion strategy. Nat Commun 2015; 6:6826. [PMID: 25851941 PMCID: PMC4403311 DOI: 10.1038/ncomms7826] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 03/03/2015] [Indexed: 11/30/2022] Open
Abstract
Integral membrane proteins (IMPs) play crucial roles in all cells and represent attractive pharmacological targets. However, functional and structural studies of IMPs are hindered by their hydrophobic nature and the fact that they are generally unstable following extraction from their native membrane environment using detergents. Here we devise a general strategy for in vivo solubilization of IMPs in structurally relevant conformations without the need for detergents or mutations to the IMP itself, as an alternative to extraction and in vitro solubilization. This technique, called SIMPLEx (solubilization of IMPs with high levels of expression), allows the direct expression of soluble products in living cells by simply fusing an IMP target with truncated apolipoprotein A-I, which serves as an amphipathic proteic ‘shield' that sequesters the IMP from water and promotes its solubilization. The study of integral membrane proteins (IMPs) is hampered by yields and the difficulty in retaining activity once they have been solubilized. Here Mizrachi et al. develop a strategy for in vivo expression and solubilization of IMPs in functionally relevant states by fusing them to truncated apolipoprotein A-I.
Collapse
Affiliation(s)
- Dario Mizrachi
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, USA
| | - Yujie Chen
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Jiayan Liu
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Hwei-Ming Peng
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Ailong Ke
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - Richard J Auchus
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Matthew P DeLisa
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, USA
| |
Collapse
|
50
|
Rosti K, Goldman A, Kajander T. Solution structure and biophysical characterization of the multifaceted signalling effector protein growth arrest specific-1. BMC BIOCHEMISTRY 2015; 16:8. [PMID: 25888394 PMCID: PMC4349606 DOI: 10.1186/s12858-015-0037-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 02/06/2015] [Indexed: 11/10/2022]
Abstract
Background The protein growth arrest specific-1 (GAS1) was discovered based on its ability to stop the cell cycle. During development it is involved in embryonic patterning, inhibits cell proliferation and mediates cell death, and has therefore been considered as a tumor suppressor. GAS1 is known to signal through two different cell membrane receptors: Rearranged during transformation (RET), and the sonic hedgehog receptor Patched-1. Sonic Hedgehog signalling is important in stem cell renewal and RET mediated signalling in neuronal survival. Disorders in both sonic hedgehog and RET signalling are connected to cancer progression. The neuroprotective effect of RET is controlled by glial cell-derived neurotrophic factor family ligands and glial cell-derived neurotrophic factor receptor alphas (GFRαs). Human Growth arrest specific-1 is a distant homolog of the GFRαs. Results We have produced and purified recombinant human GAS1 protein, and confirmed that GAS1 is a monomer in solution by static light scattering and small angle X-ray scattering analysis. The low resolution solution structure reveals that GAS1 is more elongated and flexible than the GFRαs, and the homology modelling of the individual domains show that they differ from GFRαs by lacking the amino acids for neurotrophic factor binding. In addition, GAS1 has an extended loop in the N-terminal domain that is conserved in vertebrates after the divergence of fishes and amphibians. Conclusions We conclude that GAS1 most likely differs from GFRαs functionally, based on comparative structural analysis, while it is able to bind the extracellular part of RET in a neurotrophic factor independent manner, although with low affinity in solution. Our structural characterization indicates that GAS1 differs from GFRα’s significantly also in its conformation, which probably reflects the functional differences between GAS1 and the GFRαs.
Collapse
Affiliation(s)
- Katja Rosti
- Institute of Biotechnology, Structural Biology and Biophysics, University of Helsinki, Helsinki, Finland.
| | - Adrian Goldman
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, UK. .,Department of Biosciences, Division of Biochemistry, University of Helsinki, Helsinki, Finland.
| | - Tommi Kajander
- Institute of Biotechnology, Structural Biology and Biophysics, University of Helsinki, Helsinki, Finland.
| |
Collapse
|