101
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Abstract
The thermal motion of charged proteins causes randomly fluctuating electric fields inside cells. According to the fluctuation-dissipation theorem, there is an additional friction force associated with such fluctuations. However, the impact of these fluctuations on the diffusion and dynamics of proteins in the cytoplasm is unclear. Here, we provide an order-of-magnitude estimate of this effect by treating electric field fluctuations within a generalized Langevin equation model with a time-dependent friction memory kernel. We find that electric friction is generally negligible compared to solvent friction. However, a significant slowdown of protein diffusion and dynamics is expected for biomolecules with high net charges such as intrinsically disordered proteins and RNA. The results show that direct contacts between biomolecules in a cell are not necessarily required to alter their dynamics.
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Affiliation(s)
- Dmitrii E Makarov
- Department of Chemistry and Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas 78712, United States
| | - Hagen Hofmann
- Department of Chemical and Structural Biology, Weizmann Institute of Science, 76100 Rehovot, Israel
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102
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Exploring ligand binding pathways on proteins using hypersound-accelerated molecular dynamics. Nat Commun 2021; 12:2793. [PMID: 33990583 PMCID: PMC8121818 DOI: 10.1038/s41467-021-23157-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 04/15/2021] [Indexed: 12/25/2022] Open
Abstract
Capturing the dynamic processes of biomolecular systems in atomistic detail remains difficult despite recent experimental advances. Although molecular dynamics (MD) techniques enable atomic-level observations, simulations of “slow” biomolecular processes (with timescales longer than submilliseconds) are challenging because of current computer speed limitations. Therefore, we developed a method to accelerate MD simulations by high-frequency ultrasound perturbation. The binding events between the protein CDK2 and its small-molecule inhibitors were nearly undetectable in 100-ns conventional MD, but the method successfully accelerated their slow binding rates by up to 10–20 times. Hypersound-accelerated MD simulations revealed a variety of microscopic kinetic features of the inhibitors on the protein surface, such as the existence of different binding pathways to the active site. Moreover, the simulations allowed the estimation of the corresponding kinetic parameters and exploring other druggable pockets. This method can thus provide deeper insight into the microscopic interactions controlling biomolecular processes. Molecular dynamics (MD) techniques enable atomic-level observations, but simulations of “slow” biomolecular processes are challenging because of current computer speed limitations. Here, the authors develop a method to accelerate MD simulations by high-frequency ultrasound perturbation and reveal binding events between the protein CDK2 and its small-molecule inhibitors.
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103
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Harish B, Gillilan RE, Zou J, Wang J, Raleigh DP, Royer CA. Protein unfolded states populated at high and ambient pressure are similarly compact. Biophys J 2021; 120:2592-2598. [PMID: 33961866 DOI: 10.1016/j.bpj.2021.04.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/23/2021] [Accepted: 04/29/2021] [Indexed: 10/21/2022] Open
Abstract
The relationship between the dimensions of pressure-unfolded states of proteins compared with those at ambient pressure is controversial; resolving this issue is related directly to the mechanisms of pressure denaturation. Moreover, a significant pressure dependence of the compactness of unfolded states would complicate the interpretation of folding parameters from pressure perturbation and make comparison to those obtained using alternative perturbation approaches difficult. Here, we determined the compactness of the pressure-unfolded state of a small, cooperatively folding model protein, CTL9-I98A, as a function of temperature. This protein undergoes both thermal unfolding and cold denaturation, and the temperature dependence of the compactness at atmospheric pressure is known. High-pressure small angle x-ray scattering studies, yielding the radius of gyration and high-pressure diffusion ordered spectroscopy NMR experiments, yielding the hydrodynamic radius were carried out as a function of temperature at 250 MPa, a pressure at which the protein is unfolded. The radius of gyration values obtained at any given temperature at 250 MPa were similar to those reported previously at ambient pressure, and the trends with temperature are similar as well, although the pressure-unfolded state appears to undergo more pronounced expansion at high temperature than the unfolded state at atmospheric pressure. At 250 MPa, the compaction of the unfolded chain was maximal between 25 and 30°C, and the chain expanded upon both cooling and heating. These results reveal that the pressure-unfolded state of this protein is very similar to that observed at ambient pressure, demonstrating that pressure perturbation represents a powerful approach for observing the unfolded states of proteins under otherwise near-native conditions.
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Affiliation(s)
| | | | - Junjie Zou
- Department of Chemistry, Stony Brook University, Stony Brook, New York; Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York
| | - Jinqiu Wang
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York
| | - Daniel P Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, New York; Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York
| | - Catherine A Royer
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York.
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104
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Chakraborty R, Dey S, Sil P, Paul SS, Bhattacharyya D, Bhunia A, Sengupta J, Chattopadhyay K. Conformational distortion in a fibril-forming oligomer arrests alpha-Synuclein fibrillation and minimizes its toxic effects. Commun Biol 2021; 4:518. [PMID: 33941845 PMCID: PMC8093279 DOI: 10.1038/s42003-021-02026-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 03/25/2021] [Indexed: 02/06/2023] Open
Abstract
The fibrillation pathway of alpha-Synuclein, the causative protein of Parkinson's disease, encompasses transient, heterogeneous oligomeric forms whose structural understanding and link to toxicity are not yet understood. We report that the addition of the physiologically-available small molecule heme at a sub-stoichiometric ratio to either monomeric or aggregated α-Syn, targets a His50 residue critical for fibril-formation and stabilizes the structurally-heterogeneous populations of aggregates into a minimally-toxic oligomeric state. Cryo-EM 3D reconstruction revealed a 'mace'-shaped structure of this monodisperse population of oligomers, which is comparable to a solid-state NMR Greek key-like motif (where the core residues are arranged in parallel in-register sheets with a Greek key topology at the C terminus) that forms the fundamental unit/kernel of protofilaments. Further structural analyses suggest that heme binding induces a distortion in the Greek key-like architecture of the mace oligomers, which impairs their further appending into protofilaments and fibrils. Additionally, our study reports a novel mechanism of prevention as well as reclamation of amyloid fibril formation by blocking an inter-protofilament His50 residue using a small molecule.
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Affiliation(s)
- Ritobrita Chakraborty
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Sandip Dey
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Pallabi Sil
- Department of Physics, University of Alberta, Edmonton, AB, Canada
| | - Simanta Sarani Paul
- Department of Medicine, Centre for Prion and Protein folding disease, University of Alberta, Edmonton, AB, Canada
| | - Dipita Bhattacharyya
- Department of Biophysics, Bose Institute- Centenary Campus, P-1/12C.I.T. Scheme VII-M, Kolkata, India
| | - Anirban Bhunia
- Department of Biophysics, Bose Institute- Centenary Campus, P-1/12C.I.T. Scheme VII-M, Kolkata, India
| | - Jayati Sengupta
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India.
| | - Krishnananda Chattopadhyay
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India.
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105
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Neira JL, Jiménez-Alesanco A, Rizzuti B, Velazquez-Campoy A. The nuclear localization sequence of the epigenetic factor RYBP binds to human importin α3. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2021; 1869:140670. [PMID: 33945888 DOI: 10.1016/j.bbapap.2021.140670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 04/28/2021] [Accepted: 04/29/2021] [Indexed: 11/26/2022]
Abstract
RYBP (Ring1 and YY1 binding protein, UniProt ID: Q8N488) is an epigenetic factor with a key role during embryonic development; it does also show an apoptotic function and an ubiquitin binding activity. RYBP is an intrinsically disordered protein (IDP), with a Zn-finger domain at its N-terminal region, which folds upon binding to DNA. It is predicted that RYBP has a nuclear localization sequence (NLS), comprising residues Asn58 to Lys83, to allow for nuclear translocation. We studied in this work the ability of intact RYBP to bind Impα3 and its truncated species, ΔImpα3, without the importin binding domain (IBB), by using fluorescence and circular dichroism (CD). Furthermore, the binding of the peptide matching the isolated NLS region of RYBP (NLS-RYBP) was also studied using the same methods and isothermal titration calorimetry (ITC), and in silico molecular docking. Moreover, we carried out experiments with NLS-RYBP in the absence or in the presence of NaCl (140 mM). Our results show that RYBP interacted with Impα3 and ΔImpα3, causing protein precipitation. The NLS-RYBP also interacted with both importin species (dissociation constant in the low micromolar range), at low or high ionic strength, as shown by intrinsic fluorescence and ITC. These findings indicate that the NLS region, which was mainly unfolded in isolation in solution, was essentially responsible for the binding of RYBP to each of the importin species. Furthermore, the molecular simulations predict that the anchoring of NLS-RYBP takes place in the major binding site for the NLS of cargo proteins bound to Impα3. Taken together, our findings pinpoint the theoretical predictions of the NLS region in RYBP and, more importantly, suggest that this IDP relies on an importin for its nuclear translocation.
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Affiliation(s)
- José L Neira
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain; Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain.
| | - Ana Jiménez-Alesanco
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain
| | - Bruno Rizzuti
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Adrián Velazquez-Campoy
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain; Fundación ARAID, Government of Aragón, 50018 Zaragoza, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28006 Madrid, Spain
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106
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Zhou T, Fleming JR, Lange S, Hessel AL, Bogomolovas J, Stronczek C, Grundei D, Ghassemian M, Biju A, Börgeson E, Bullard B, Linke WA, Chen J, Kovermann M, Mayans O. Molecular Characterisation of Titin N2A and Its Binding of CARP Reveals a Titin/Actin Cross-linking Mechanism. J Mol Biol 2021; 433:166901. [PMID: 33647290 PMCID: PMC8052292 DOI: 10.1016/j.jmb.2021.166901] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/14/2021] [Accepted: 02/22/2021] [Indexed: 12/16/2022]
Abstract
Striated muscle responds to mechanical overload by rapidly up-regulating the expression of the cardiac ankyrin repeat protein, CARP, which then targets the sarcomere by binding to titin N2A in the I-band region. To date, the role of this interaction in the stress response of muscle remains poorly understood. Here, we characterise the molecular structure of the CARP-receptor site in titin (UN2A) and its binding of CARP. We find that titin UN2A contains a central three-helix bundle fold (ca 45 residues in length) that is joined to N- and C-terminal flanking immunoglobulin domains by long, flexible linkers with partial helical content. CARP binds titin by engaging an α-hairpin in the three-helix fold of UN2A, the C-terminal linker sequence, and the BC loop in Ig81, which jointly form a broad binding interface. Mutagenesis showed that the CARP/N2A association withstands sequence variations in titin N2A and we use this information to evaluate 85 human single nucleotide variants. In addition, actin co-sedimentation, co-transfection in C2C12 cells, proteomics on heart lysates, and the mechanical response of CARP-soaked myofibrils imply that CARP induces the cross-linking of titin and actin myofilaments, thereby increasing myofibril stiffness. We conclude that CARP acts as a regulator of force output in the sarcomere that preserves muscle mechanical performance upon overload stress.
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Affiliation(s)
- Tiankun Zhou
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | | | - Stephan Lange
- Division of Cardiology, School of Medicine, University of California, San Diego 92093, CA, USA; Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, Gothenburg 413 45, Sweden
| | - Anthony L Hessel
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Julius Bogomolovas
- School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159 Mannheim, Germany
| | - Chiara Stronczek
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - David Grundei
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Majid Ghassemian
- Department of Chemistry and Biochemistry, University of California, San Diego 92093, CA, USA
| | - Andrea Biju
- Division of Cardiology, School of Medicine, University of California, San Diego 92093, CA, USA
| | - Emma Börgeson
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, Gothenburg 413 45, Sweden
| | - Belinda Bullard
- Department of Biology, University of York, York YO10 5DD, UK
| | - Wolfgang A Linke
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Ju Chen
- School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Michael Kovermann
- Department of Chemistry, University of Konstanz, 78457 Konstanz, Germany.
| | - Olga Mayans
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany.
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107
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Ahmed MC, Skaanning LK, Jussupow A, Newcombe EA, Kragelund BB, Camilloni C, Langkilde AE, Lindorff-Larsen K. Refinement of α-Synuclein Ensembles Against SAXS Data: Comparison of Force Fields and Methods. Front Mol Biosci 2021; 8:654333. [PMID: 33968988 PMCID: PMC8100456 DOI: 10.3389/fmolb.2021.654333] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/12/2021] [Indexed: 12/22/2022] Open
Abstract
The inherent flexibility of intrinsically disordered proteins (IDPs) makes it difficult to interpret experimental data using structural models. On the other hand, molecular dynamics simulations of IDPs often suffer from force-field inaccuracies, and long simulation times or enhanced sampling methods are needed to obtain converged ensembles. Here, we apply metainference and Bayesian/Maximum Entropy reweighting approaches to integrate prior knowledge of the system with experimental data, while also dealing with various sources of errors and the inherent conformational heterogeneity of IDPs. We have measured new SAXS data on the protein α-synuclein, and integrate this with simulations performed using different force fields. We find that if the force field gives rise to ensembles that are much more compact than what is implied by the SAXS data it is difficult to recover a reasonable ensemble. On the other hand, we show that when the simulated ensemble is reasonable, we can obtain an ensemble that is consistent with the SAXS data, but also with NMR diffusion and paramagnetic relaxation enhancement data.
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Affiliation(s)
- Mustapha Carab Ahmed
- Structural Biology and NMR Laboratory, Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
| | - Line K Skaanning
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Alexander Jussupow
- Department of Chemistry, Institute for Advanced Study, Technical University of Munich, Munich, Germany
| | - Estella A Newcombe
- Structural Biology and NMR Laboratory, Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark.,Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
| | - Carlo Camilloni
- Department of Chemistry, Institute for Advanced Study, Technical University of Munich, Munich, Germany.,Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Annette E Langkilde
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory, Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
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108
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Structural insight into the role of the PAS domainfor signal transduction in sensor-kinase BvgS. J Bacteriol 2021; 203:JB.00614-20. [PMID: 33619154 PMCID: PMC8092167 DOI: 10.1128/jb.00614-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The two-component system BvgAS controls the virulence regulon in Bordetella pertussis BvgS is the prototype of a family of sensor histidine-kinases harboring periplasmic Venus flytrap (VFT) domains. The VFT domains are connected to the cytoplasmic kinase moiety by helical linkers separated by a Per-ARNT-Sim (PAS) domain. Antagonism between the two linkers, as one forms a coiled coil when the other is dynamic and vice versa, regulates BvgS activity. Here we solved the structure of the intervening PAS domain by X-ray crystallography. Two forms were obtained that notably differ by the connections between the PAS core domain and the flanking helical linkers. Structure-guided mutagenesis indicated that those connections participate in the regulation of BvgS activity. The PAS domain thus appears to function as a switch-facilitator module whose conformation determines the output of the system. As many BvgS homologs have similar architectures, the mechanisms unveiled here are likely to generally apply to the regulation of sensor-histidine kinases of that family.IMPORTANCEThe whooping cough agent Bordetella pertussis colonizes the human respiratory tract using virulence factors co-regulated by the sensory transduction system BvgAS. BvgS is a model for a family of sensor-kinase proteins, some of which are found in important bacterial pathogens. BvgS functions as a kinase or a phosphatase depending on external signals, which determines if B. pertussis is virulent or avirulent. Deciphering its mode of action might thus lead to new ways of fighting infections. Here we used X-ray crystallography to solve the three-dimensional structure of the domain that precedes the enzymatic moiety and identified features that regulate BvgS activity. As many sensor-kinases of the BvgS family harbor homologous domains, the mechanism unveiled here might be of general relevance.
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109
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Kaplan AR, Olson R, Alexandrescu AT. Protein yoga: Conformational versatility of the Hemolysin II C-terminal domain detailed by NMR structures for multiple states. Protein Sci 2021; 30:990-1005. [PMID: 33733504 DOI: 10.1002/pro.4066] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 03/10/2021] [Accepted: 03/13/2021] [Indexed: 11/05/2022]
Abstract
The C-terminal domain of Bacillus cereus hemolysin II (HlyIIC), stabilizes the trans-membrane-pore formed by the HlyII toxin and may aid in target cell recognition. Initial efforts to determine the NMR structure of HlyIIC were hampered by cis/trans isomerization about the single proline at position 405 that leads to doubling of NMR resonances. We used the mutant P405M-HlyIIC that eliminates the cis proline to determine the NMR structure of the domain, which revealed a novel fold. Here, we extend earlier studies to the NMR structure determination of the cis and trans states of WT-HlyIIC that exist simultaneously in solution. The primary structural differences between the cis and trans states are in the loop that contains P405, and structurally adjacent loops. Thermodynamic linkage analysis shows that at 25 C the cis proline, which already has a large fraction of 20% in the unfolded protein, increases to 50% in the folded state due to coupling with the global stability of the domain. The P405M or P405A substitutions eliminate heterogeneity due to proline isomerization but lead to the formation of a new dimeric species. The NMR structure of the dimer shows that it is formed through domain-swapping of strand β5, the last segment of secondary structure following P405. The presence of P405 in WT-HlyIIC strongly disfavors the dimer compared to the P405M-HlyIIC or P405A-HlyIIC mutants. The WT proline may thus act as a "gatekeeper," warding off aggregative misfolding.
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Affiliation(s)
- Anne R Kaplan
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Rich Olson
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, Middletown, Connecticut, USA
| | - Andrei T Alexandrescu
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
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110
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Pinet L, Wang YH, Deville C, Lescop E, Guerlesquin F, Badache A, Bontems F, Morellet N, Durand D, Assrir N, van Heijenoort C. Structural and dynamic characterization of the C-terminal tail of ErbB2: Disordered but not random. Biophys J 2021; 120:1869-1882. [PMID: 33741354 DOI: 10.1016/j.bpj.2021.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 02/26/2021] [Accepted: 03/03/2021] [Indexed: 01/23/2023] Open
Abstract
ErbB2 (or HER2) is a receptor tyrosine kinase overexpressed in some breast cancers and associated with poor prognosis. Treatments targeting the receptor extracellular and kinase domains have greatly improved disease outcome in the last 20 years. In parallel, the structures of these domains have been described, enabling better mechanistic understanding of the receptor function and targeted inhibition. However, the ErbB2 disordered C-terminal cytoplasmic tail (CtErbB2) remains very poorly characterized in terms of structure, dynamics, and detailed functional mechanism. Yet, it is where signal transduction is triggered via phosphorylation of tyrosine residues and carried out via interaction with adaptor proteins. Here, we report the first description, to our knowledge, of the ErbB2 disordered tail at atomic resolution using NMR, complemented by small-angle x-ray scattering. We show that although no part of CtErbB2 has any fully populated secondary or tertiary structure, it contains several transient α-helices and numerous transient polyproline II helices, populated up to 20 and 40%, respectively, and low but significant compaction. The presence of some structural elements suggests, along the lines of the results obtained for EGFR (ErbB1), that they may have a functional role in ErbB2's autoregulation processes. In addition, the transient formation of polyproline II helices is compliant with previously suggested interactions with SH3 domains. All in all, our in-depth structural study opens perspectives in the mechanistic understanding of ErbB2.
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Affiliation(s)
- Louise Pinet
- Institut de Chimie des Substances Naturelles, CNRS UPR2301, Université Paris-Saclay, Gif-sur-Yvette, France; Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Ying-Hui Wang
- Institut de Chimie des Substances Naturelles, CNRS UPR2301, Université Paris-Saclay, Gif-sur-Yvette, France; SGS Taiwan LTD, New Taipei City, Taiwan
| | - Célia Deville
- Institut de Chimie des Substances Naturelles, CNRS UPR2301, Université Paris-Saclay, Gif-sur-Yvette, France; IGBMC, University of Strasbourg, CNRS UMR, Illkirch, France
| | - Ewen Lescop
- Institut de Chimie des Substances Naturelles, CNRS UPR2301, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Françoise Guerlesquin
- LISM, Institut de Microbiologie de la Méditerranée, CNRS and Aix-Marseille University, Marseille, France
| | - Ali Badache
- Centre de Recherche en Cancérologie de Marseille, Aix-Marseille Univ, INSERM, Institut Paoli-Calmettes, CNRS, Marseille, France
| | - François Bontems
- Institut de Chimie des Substances Naturelles, CNRS UPR2301, Université Paris-Saclay, Gif-sur-Yvette, France; Department of Virology, Institut Pasteur, CNRS UMR 3569, Paris, France
| | - Nelly Morellet
- Institut de Chimie des Substances Naturelles, CNRS UPR2301, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Dominique Durand
- I2BC, Université Paris-Saclay, CNRS UMR 9198, Gif-sur-Yvette, France
| | - Nadine Assrir
- Institut de Chimie des Substances Naturelles, CNRS UPR2301, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Carine van Heijenoort
- Institut de Chimie des Substances Naturelles, CNRS UPR2301, Université Paris-Saclay, Gif-sur-Yvette, France.
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111
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Selecting Subpopulations of High-Quality Protein Conformers among Conformational Mixtures of Recombinant Bovine MMP-9 Solubilized from Inclusion Bodies. Int J Mol Sci 2021; 22:ijms22063020. [PMID: 33809594 PMCID: PMC8001920 DOI: 10.3390/ijms22063020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/03/2021] [Accepted: 03/12/2021] [Indexed: 12/30/2022] Open
Abstract
A detailed workflow to analyze the physicochemical characteristics of mammalian matrix metalloproteinase (MMP-9) protein species obtained from protein aggregates (inclusion bodies-IBs) was followed. MMP-9 was recombinantly produced in the prokaryotic microbial cell factories Clearcoli (an engineered form of Escherichia coli) and Lactococcus lactis, mainly forming part of IBs and partially recovered under non-denaturing conditions. After the purification by affinity chromatography of solubilized MMP-9, four protein peaks were obtained. However, so far, the different conformational protein species forming part of IBs have not been isolated and characterized. Therefore, with the aim to link the physicochemical characteristics of the isolated peaks with their biological activity, we set up a methodological approach that included dynamic light scattering (DLS), circular dichroism (CD), and spectrofluorometric analysis confirming the separation of subpopulations of conformers with specific characteristics. In protein purification procedures, the detailed analysis of the individual physicochemical properties and the biological activity of protein peaks separated by chromatographic techniques is a reliable source of information to select the best-fitted protein populations.
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112
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Ayyappan S, Dharan PS, Krishnan A, Marira RR, Lambert M, Manna TK, Vijayan V. SxIP binding disrupts the constitutive homodimer interface of EB1 and stabilizes EB1 monomer. Biophys J 2021; 120:2019-2029. [PMID: 33737159 DOI: 10.1016/j.bpj.2021.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 02/16/2021] [Accepted: 03/01/2021] [Indexed: 11/16/2022] Open
Abstract
SxIP is a microtubule tip localizing signal found in many +TIP proteins that bind to the hydrophobic cavity of the C-terminal domain of end binding protein 1 (EB1) and then positively regulate the microtubule plus-end tracking of EBs. However, the exact mechanism of microtubule activation of EBs in the presence of SxIP signaling motif is not known. Here, we studied the effect of SxIP peptide on the native conformation of EB1 in solution. Using various NMR experiments, we found that SxIP peptide promoted the dissociation of natively formed EB1 dimer. We also discovered that I224A mutation of EB1 resulted in an unfolded C-terminal domain, which upon binding with the SxIP motif folded to its native structure. Molecular dynamics simulations also confirmed the relative structural stability of EB1 monomer in the SxIP bound state. Residual dipolar couplings and heteronuclear NOE analysis suggested that the binding of SxIP peptide at the C-terminal domain of EB1 decreased the dynamics and conformational flexibility of the N-terminal domain involved in EB1-microtubule interaction. The SxIP-induced disruption of the dimeric interactions in EB1, coupled with the reduction in conformational flexibility of the N-terminal domain of EB1, might facilitate the microtubule association of EB1.
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Affiliation(s)
- Shine Ayyappan
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
| | - Pooja S Dharan
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
| | - Arya Krishnan
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
| | - Renjith R Marira
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
| | - Mahil Lambert
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
| | - Tapas K Manna
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
| | - Vinesh Vijayan
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India.
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113
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Malomuzh NP, Khorolskyi AV. Analyzing the Size of Albumin Macromolecules in Aqueous Solutions. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2021. [DOI: 10.1134/s0036024421020199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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114
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Barbee MH, Wright ZM, Allen BP, Taylor HF, Patteson EF, Knight AS. Protein-Mimetic Self-Assembly with Synthetic Macromolecules. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02826] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Meredith H. Barbee
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Zoe M. Wright
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Benjamin P. Allen
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Hailey F. Taylor
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Emily F. Patteson
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Abigail S. Knight
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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115
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Sarimov RM, Binhi VN, Matveeva TA, Penkov NV, Gudkov SV. Unfolding and Aggregation of Lysozyme under the Combined Action of Dithiothreitol and Guanidine Hydrochloride: Optical Studies. Int J Mol Sci 2021; 22:2710. [PMID: 33800175 PMCID: PMC7962454 DOI: 10.3390/ijms22052710] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 11/16/2022] Open
Abstract
Using a number of optical techniques (interferometry, dynamic light scattering, and spectroscopy), denaturation of hen egg white lysozyme (HEWL) by treatment with a combination of dithiothreitol (DTT) and guanidine hydrochloride (GdnHCl) has been investigated. The denaturing solutions were selected so that protein denaturation occurred with aggregation (Tris-HCl pH = 8.0, 50 mM, DTT 30 mM) or without aggregation (Tris-HCl pH = 8.0, 50 mM, DTT 30 mM, GdnHCl 6 M) and can be evaluated after 60 min of treatment. It has been found that denatured by solution with 6 M GdnHCl lysozyme completely loses its enzymatic activity after 30 min and the size of the protein molecule increases by 1.5 times, from 3.8 nm to 5.7 nm. Denaturation without of GdnHCl led to aggregation with preserving about 50% of its enzymatic activity. Denaturation of HEWL was examined using interferometry. Previously, it has been shown that protein denaturation that occurs without subsequent aggregation leads to an increase in the refractive index (Δn ~ 4.5 × 10-5). This is most likely due to variations in the HEWL-solvent interface area. By applying modern optical techniques conjointly, it has been possible to obtain information on the nature of time-dependent changes that occur inside a protein and its hydration shell as it undergoes denaturation.
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Affiliation(s)
- Ruslan M. Sarimov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Vavilov St., 38, 119991 Moscow, Russia; (R.M.S.); (V.N.B.); (T.A.M.)
| | - Vladimir N. Binhi
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Vavilov St., 38, 119991 Moscow, Russia; (R.M.S.); (V.N.B.); (T.A.M.)
| | - Tatiana A. Matveeva
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Vavilov St., 38, 119991 Moscow, Russia; (R.M.S.); (V.N.B.); (T.A.M.)
| | - Nikita V. Penkov
- Institute of Cell Biophysics of the Russian Academy of Sciences, PSCBR RAS, Institutskaya St., 3, Pushchino, 142290 Moscow, Russia;
| | - Sergey V. Gudkov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Vavilov St., 38, 119991 Moscow, Russia; (R.M.S.); (V.N.B.); (T.A.M.)
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116
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Mierczynska-Vasilev A, Bindon K, Gawel R, Smith P, Vasilev K, Butt HJHJ, Koynov K. Fluorescence correlation spectroscopy to unravel the interactions between macromolecules in wine. Food Chem 2021; 352:129343. [PMID: 33652194 DOI: 10.1016/j.foodchem.2021.129343] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/07/2021] [Accepted: 02/08/2021] [Indexed: 11/19/2022]
Abstract
In this work, the interaction of wine macromolecules with a bovine serum albumin (BSA) was investigated using fluorescence correlation spectroscopy (FCS). FCS offers the opportunity to study molecular and macromolecular aggregation without disturbing the wine by introducing only very small amounts of fluorescently labelled molecules to the system. It was observed that the diffusion coefficient of fluorescently labelled BSA varies with the addition of wine macromolecules, indicating changes in the protein conformation and the formation of complexes and aggregates. The addition of a wine polysaccharide rhamnogalacturonan II-enriched fraction led to aggregation, while addition of a mannoprotein-enriched fraction exhibited a protective effect on protein aggregation. Proteins strongly interacted with tannins, leading to the precipitation of protein-tannin complexes, while the presence of polysaccharides prevented this precipitation. Finally, the application of FCS was demonstrated in real wines, to investigate the problem of protein haze formation through live monitoring of heat-induced aggregation in wine.
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Affiliation(s)
- Agnieszka Mierczynska-Vasilev
- The Australian Wine Research Institute, Waite Precinct, Hartley Grove cnr Paratoo Road, Urrbrae (Adelaide) SA 5064, PO Box 197, Glen Osmond, SA 5064, Australia.
| | - Keren Bindon
- The Australian Wine Research Institute, Waite Precinct, Hartley Grove cnr Paratoo Road, Urrbrae (Adelaide) SA 5064, PO Box 197, Glen Osmond, SA 5064, Australia.
| | - Richard Gawel
- The Australian Wine Research Institute, Waite Precinct, Hartley Grove cnr Paratoo Road, Urrbrae (Adelaide) SA 5064, PO Box 197, Glen Osmond, SA 5064, Australia.
| | - Paul Smith
- The Australian Wine Research Institute, Waite Precinct, Hartley Grove cnr Paratoo Road, Urrbrae (Adelaide) SA 5064, PO Box 197, Glen Osmond, SA 5064, Australia; Wine Australia, P.O. Box 660, Kent Town, SA 5071, Australia
| | - Krasimir Vasilev
- Unit of STEM, University of South Australia, Mawson Lakes Campus, Mawson Lakes, SA 5095, Australia.
| | | | - Kaloian Koynov
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
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117
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118
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Kumar A, Kumar P, Aarthy M, Singh SK, Giri R. Experiments and simulation on ZIKV NS2B-NS3 protease reveal its complex folding. Virology 2021; 556:110-123. [PMID: 33561698 DOI: 10.1016/j.virol.2021.01.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 11/29/2020] [Accepted: 01/21/2021] [Indexed: 11/18/2022]
Abstract
Zika virus has been identified in various body fluids such as semen, urine, saliva, cerebrospinal fluid, and vaginal secretion of an infected individual. The pH of these fluids varies from mildly acidic to mildly alkaline. So it is imperative to understand the impact of these conditions on viral protein functioning. We investigated the NS2B-NS3 protease stability and its activity in different denaturing environments. Finding indicates that NS2B-NS3 protease maintains stability at pH 4.8-8.7. Thus it suggests that the complex remains functionally active to hydrolyze the polyprotein within a diverse environmental condition such as variable pH. Despite a stable structure at a broad pH range, a change in environmental conditions dramatically influence its protease activity. Moreover, it is susceptible to structural transformation leading to increased β-strand or helix content in the presence of alcohol. This study may help further to understand the folding-function relationship of the general flaviviral protease complex.
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Affiliation(s)
- Ankur Kumar
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, 175005, Himachal Pradesh, India
| | - Prateek Kumar
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, 175005, Himachal Pradesh, India
| | - Murali Aarthy
- Department of Bioinformatics, Computer Aided Drug Design and Molecular Modeling Laboratory, Alagappa University, Science Block, Karaikudi, 630003, Tamil Nadu, India
| | - Sanjeev Kumar Singh
- Department of Bioinformatics, Computer Aided Drug Design and Molecular Modeling Laboratory, Alagappa University, Science Block, Karaikudi, 630003, Tamil Nadu, India
| | - Rajanish Giri
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, 175005, Himachal Pradesh, India.
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119
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Urea titration of a lipase from Pseudomonas sp. reveals four different conformational states, with a stable partially folded state explaining its high aggregation propensity. Int J Biol Macromol 2021; 174:32-41. [PMID: 33508357 DOI: 10.1016/j.ijbiomac.2021.01.153] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 01/14/2021] [Accepted: 01/22/2021] [Indexed: 10/22/2022]
Abstract
The conversion of soluble proteins into amyloid fibrils has importance in protein chemistry, biology, biotechnology and medicine. A novel lipase from Pseudomonas sp. was previously shown to have an extremely high aggregation propensity. It was therefore herein studied to elucidate the physicochemical and structural determinants of this extreme behaviour. Amyloid-like structures were found to form in samples up to 2.5-3.0 M using Thioflavin T fluorescence and Congo red binding assays. However, dynamic light scattering (DLS), static light scattering and turbidimetry revealed the existence of aggregates up to 4.0 M urea, without amyloid-like structure. Two monomeric conformational states were detected with intrinsic fluorescence, 8-anilinonaphthalene-1-sulfonate (ANS) binding and circular dichroism. These were further characterized in 7.5 M and 4.5 M urea using enzymatic activity measurements, tryptophan fluorescence quenching, DLS and nuclear magnetic resonance (NMR) and were found to consist of a largely disordered and a partially folded state, respectively, with the latter appearing stable, cooperative, fairly compact, non-active, α-helical, with largely buried hydrophobic residues. The persistence of a stable structure up to high concentrations of urea, in the absence of sequence characteristics typical of a high intrinsic aggregation propensity, explains the high tendency of this enzyme to form amyloid-like structures.
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120
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Liang W, Wied P, Carraro F, Sumby CJ, Nidetzky B, Tsung CK, Falcaro P, Doonan CJ. Metal–Organic Framework-Based Enzyme Biocomposites. Chem Rev 2021; 121:1077-1129. [DOI: 10.1021/acs.chemrev.0c01029] [Citation(s) in RCA: 166] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Weibin Liang
- Department of Chemistry and Centre for Advanced Nanomaterials, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Peter Wied
- Institute of Physical and Theoretical Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
| | - Francesco Carraro
- Institute of Physical and Theoretical Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
| | - Christopher J. Sumby
- Department of Chemistry and Centre for Advanced Nanomaterials, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Bernd Nidetzky
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 12/1, 8010 Graz, Austria
| | - Chia-Kuang Tsung
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Paolo Falcaro
- Institute of Physical and Theoretical Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
| | - Christian J. Doonan
- Department of Chemistry and Centre for Advanced Nanomaterials, The University of Adelaide, Adelaide, South Australia 5005, Australia
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121
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Hornos F, Feng HZ, Rizzuti B, Palomino-Schätzlein M, Wieczorek D, Neira JL, Jin JP. The muscle-relaxing C-terminal peptide from troponin I populates a nascent helix, facilitating binding to tropomyosin with a potent therapeutic effect. J Biol Chem 2021; 296:100228. [PMID: 33814345 PMCID: PMC7948816 DOI: 10.1074/jbc.ra120.016012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 12/16/2020] [Accepted: 12/22/2020] [Indexed: 11/06/2022] Open
Abstract
The conserved C-terminal end segment of troponin I (TnI) plays a critical role in regulating muscle relaxation. This function is retained in the isolated C-terminal 27 amino acid peptide (residues 184-210) of human cardiac TnI (HcTnI-C27): When added to skinned muscle fibers, HcTnI-C27 reduces the Ca2+-sensitivity of activated myofibrils and facilitates relaxation without decreasing the maximum force production. However, the underlying mechanism of HcTnI-C27 function is unknown. We studied the conformational preferences of HcTnI-C27 and a myopathic mutant, Arg192His, (HcTnI-C27-H). Both peptides were mainly disordered in aqueous solution with a nascent helix involving residues from Trp191 to Ile195, as shown by NMR analysis and molecular dynamics simulations. The population of nascent helix was smaller in HcTnI-C27-H than in HcTnI-C27, as shown by circular dichroism (CD) titrations. Fluorescence and isothermal titration calorimetry (ITC) showed that both peptides bound tropomyosin (αTm), with a detectably higher affinity (∼10 μM) of HcTnI-C27 than that of HcTnI-C27-H (∼15 μM), consistent with an impaired Ca2+-desensitization effect of the mutant peptide on skinned muscle strips. Upon binding to αTm, HcTnI-C27 acquired a weakly stable helix-like conformation involving residues near Trp191, as shown by transferred nuclear Overhauser effect spectroscopy and hydrogen/deuterium exchange experiments. With the potent Ca2+-desensitization effect of HcTnI-C27 on skinned cardiac muscle from a mouse model of hypertrophic cardiomyopathy, the data support that the C-terminal end domain of TnI can function as an isolated peptide with the intrinsic capacity of binding tropomyosin, providing a promising therapeutic approach to selectively improve diastolic function of the heart.
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MESH Headings
- Amino Acid Sequence
- Amino Acid Substitution
- Animals
- Binding Sites
- Calcium/metabolism
- Cardiomyopathy, Hypertrophic/genetics
- Cardiomyopathy, Hypertrophic/metabolism
- Cardiomyopathy, Hypertrophic/pathology
- Cardiomyopathy, Hypertrophic/prevention & control
- Disease Models, Animal
- Gene Expression
- Humans
- Kinetics
- Mice
- Molecular Docking Simulation
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Muscle Relaxation
- Mutation
- Myofibrils/drug effects
- Myofibrils/metabolism
- Myofibrils/pathology
- Peptides/chemistry
- Peptides/genetics
- Peptides/metabolism
- Peptides/pharmacology
- Protein Binding
- Protein Conformation, alpha-Helical
- Protein Interaction Domains and Motifs
- Sequence Alignment
- Sequence Homology, Amino Acid
- Substrate Specificity
- Tropomyosin/chemistry
- Tropomyosin/genetics
- Tropomyosin/metabolism
- Troponin I/chemistry
- Troponin I/genetics
- Troponin I/metabolism
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Affiliation(s)
- Felipe Hornos
- IDIBE, Universidad Miguel Hernández, Alicante, Spain
| | - Han-Zhong Feng
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, Cosenza, Italy
| | | | - David Wieczorek
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cinncinnnati, Ohio, USA
| | - José L Neira
- IDIBE, Universidad Miguel Hernández, Alicante, Spain; Instituto de Biocomputación y Física de Sistemas Complejos, Zaragoza, Spain.
| | - J-P Jin
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA.
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122
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Reichheld SE, Muiznieks LD, Huynh Q, Wang N, Ing C, Miao M, Sitarz EE, Pomès R, Sharpe S, Keeley FW. The evolutionary background and functional consequences of the rs2071307 polymorphism in human tropoelastin. Biopolymers 2020; 112:e23414. [PMID: 33351193 DOI: 10.1002/bip.23414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 01/01/2023]
Abstract
Elastin is a major polymeric protein of the extracellular matrix, providing critical properties of extensibility and elastic recoil. The rs2071307 genomic polymorphism, resulting in the substitution of a serine for a glycine residue in a VPG motif in tropoelastin, has an unusually high minor allele frequency in humans. A consequence of such allelic heterozygosity would be the presence of a heterogeneous elastin polymer in up to 50% of the population, a situation which appears to be unique to Homo sapiens. VPG motifs are extremely common in hydrophobic domains of tropoelastins and are the sites of transient β-turns that are essential for maintaining the conformational flexibility required for its function as an entropic elastomer. Earlier data demonstrated that single amino acid substitutions in tropoelastin can have functional consequences for polymeric elastin, particularly when present in mixed polymers. Here, using NMR and molecular dynamics approaches, we show the rs2071307 polymorphism reduces local propensity for β-turn formation, with a consequent increase in polypeptide hydration and an expansion of the conformational ensemble manifested as an increased hydrodynamic radius, radius of gyration and asphericity. Furthermore, this substitution affects functional properties of polymeric elastin, particularly in heterogeneous polymers mimicking allelic heterozygosity. We discuss whether such effects, together with the unusually high minor allele frequency of the polymorphism, could imply some some evolutionary advantage for the heterozygous state.
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Affiliation(s)
- Sean E Reichheld
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA
| | - Lisa D Muiznieks
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA.,Elvesys Microfluidics Innovation Center, 172 rue de Charonne, 75011, Paris, France
| | - Quang Huynh
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA
| | - Nick Wang
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA.,135 W 52nd St. Apt 20A, 10019-7691, New York, New York, USA
| | - Christopher Ing
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA.,ProteinQure, Suite 304, 119 Spadina Avenue, M5V2L1, Toronto, Ontario, Canada
| | - Ming Miao
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA
| | - Eva E Sitarz
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA
| | - Régis Pomès
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Simon Sharpe
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Fred W Keeley
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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123
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Wei J, Liu Y, Song F. Coarse-grained simulation of the translational and rotational diffusion of globular proteins by dissipative particle dynamics. J Chem Phys 2020; 153:234902. [PMID: 33353321 DOI: 10.1063/5.0025620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
With simplified interactions and degrees of freedom, coarse-grained (CG) simulations have been successfully applied to study the translational and rotational diffusion of proteins in solution. However, in order to reach larger lengths and longer timescales, many CG simulations employ an oversimplified model for proteins or an implicit-solvent model in which the hydrodynamic interactions are ignored, and thus, the real kinetics are more or less unfaithful. In this work, we develop a CG model based on the dissipative particle dynamics (DPD) that can be universally applied to different types of proteins. The proteins are modeled as a group of rigid DPD beads without conformational changes. The fluids (including solvent and ions) are also modeled as DPD beads. The electrostatic interactions between charged species are explicitly considered by including charge distributions on DPD particles. Moreover, a surface friction between the protein and fluid beads is applied to control the slip boundary condition. With this model, we investigate the self-diffusion of a single globular protein in bulk solution. The translational and rotational diffusion coefficients of the protein can be tuned by the surface frictional constant to fit the predictions of the Stokes-Einstein (SE) relation. We find that both translational and rotational diffusion coefficients that meet with the prediction of the SE relation based on experimental results of the hydrodynamic radius are reached at almost the same frictional constant for different types of proteins. Such scaling behavior indicates that the model can be applied to simulate the translational and rotational diffusion together for various types of proteins.
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Affiliation(s)
- Jiachen Wei
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yawei Liu
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Fan Song
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
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124
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Sahli L, Boire A, Solé-Jamault V, Rogniaux H, Giuliani A, Roblin P, Renard D. New exploration of the γ-gliadin structure through its partial hydrolysis. Int J Biol Macromol 2020; 165:654-664. [PMID: 32991891 DOI: 10.1016/j.ijbiomac.2020.09.136] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/18/2020] [Accepted: 09/18/2020] [Indexed: 11/25/2022]
Abstract
The partial enzymatic hydrolysis of wheat gliadins constitutes an interesting tool to unravel their structural specificity. In this work, the structure and conformation of γ-gliadin were investigated through its limited chymotrypsic digestion. Using a combination of computational, biochemical and biophysical tools, we studied each of its N and C terminal domains. Our results reveal that γ-gliadin is a partially disordered protein with an unfolded N-terminal domain surprisingly resistant to chymotrypsin and a folded C-terminal domain. Using spectroscopic tools, we showed that structural transitions occured over the disordered N-terminal domain for decreasing ethanol/water ratios. Using SAXS measurements, low-resolution 3D structures of γ-gliadin were proposed. To relate the repeated motifs of the N-terminal domain of γ-gliadin to its structure, engineered peptide models PQQPY/F were also studied. Overall results demonstrated similarities between the N-terminal domain and its derived model peptides. Our findings support the use of these peptides as general templates for understanding the wheat protein assembly and dynamics.
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Affiliation(s)
- Line Sahli
- INRAE, UR1268 Biopolymers Interactions Assemblies, 44300 Nantes, France
| | - Adeline Boire
- INRAE, UR1268 Biopolymers Interactions Assemblies, 44300 Nantes, France
| | | | - Hélène Rogniaux
- INRAE, UR1268 Biopolymers Interactions Assemblies, 44300 Nantes, France; INRAE, BIBS Platform, 44300 Nantes, France
| | - Alexandre Giuliani
- DISCO Beamline, Synchrotron Soleil, l'Orme des Merisiers, 91192 Gif sur Yvette, France; UAR 1008, Transform, INRAE, BP 71627, F-44316, Nantes, France
| | - Pierre Roblin
- Laboratoire de Génie Chimique and Fédération de Recherche FERMAT, 4 allée Emile Monso, 31030 Toulouse, France
| | - Denis Renard
- INRAE, UR1268 Biopolymers Interactions Assemblies, 44300 Nantes, France.
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125
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Locking mixed-lineage kinase domain-like protein in its auto-inhibited state prevents necroptosis. Proc Natl Acad Sci U S A 2020; 117:33272-33281. [PMID: 33318170 PMCID: PMC7777204 DOI: 10.1073/pnas.2017406117] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
As an alternative pathway of controlled cell death, necroptosis can be triggered by tumor necrosis factor via the kinases RIPK1/RIPK3 and the effector protein mixed-lineage kinase domain-like protein (MLKL). Upon activation, MLKL oligomerizes and integrates into the plasma membrane via its executioner domain. Here, we present the X-ray and NMR costructures of the human MLKL executioner domain covalently bound via Cys86 to a xanthine class inhibitor. The structures reveal that the compound stabilizes the interaction between the auto-inhibitory brace helix α6 and the four-helix bundle by stacking to Phe148. An NMR-based functional assay observing the conformation of this helix showed that the F148A mutant is unresponsive to the compound, providing further evidence for the importance of this interaction. Real-time and diffusion NMR studies demonstrate that xanthine derivatives inhibit MLKL oligomerization. Finally, we show that the other well-known MLKL inhibitor Necrosulfonamide, which also covalently modifies Cys86, must employ a different mode of action.
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126
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Grist SM, Mourdoukoutas AP, Herr AE. 3D projection electrophoresis for single-cell immunoblotting. Nat Commun 2020; 11:6237. [PMID: 33277486 PMCID: PMC7718224 DOI: 10.1038/s41467-020-19738-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 10/20/2020] [Indexed: 12/21/2022] Open
Abstract
Immunoassays and mass spectrometry are powerful single-cell protein analysis tools; however, interfacing and throughput bottlenecks remain. Here, we introduce three-dimensional single-cell immunoblots to detect both cytosolic and nuclear proteins. The 3D microfluidic device is a photoactive polyacrylamide gel with a microwell array-patterned face (xy) for cell isolation and lysis. Single-cell lysate in each microwell is "electrophoretically projected" into the 3rd dimension (z-axis), separated by size, and photo-captured in the gel for immunoprobing and confocal/light-sheet imaging. Design and analysis are informed by the physics of 3D diffusion. Electrophoresis throughput is > 2.5 cells/s (70× faster than published serial sampling), with 25 immunoblots/mm2 device area (>10× increase over previous immunoblots). The 3D microdevice design synchronizes analyses of hundreds of cells, compared to status quo serial analyses that impart hours-long delay between the first and last cells. Here, we introduce projection electrophoresis to augment the heavily genomic and transcriptomic single-cell atlases with protein-level profiling.
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Affiliation(s)
- Samantha M Grist
- Department of Bioengineering, University of California, Berkeley, USA
| | - Andoni P Mourdoukoutas
- Department of Bioengineering, University of California, Berkeley, USA
- UC Berkeley - UCSF Graduate Program in Bioengineering, Berkeley, USA
| | - Amy E Herr
- Department of Bioengineering, University of California, Berkeley, USA.
- UC Berkeley - UCSF Graduate Program in Bioengineering, Berkeley, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
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127
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Leite JP, Gimeno A, Taboada P, Jiménez-Barbero JJ, Gales L. Dissection of the key steps of amyloid-β peptide 1-40 fibrillogenesis. Int J Biol Macromol 2020; 164:2240-2246. [PMID: 32771514 DOI: 10.1016/j.ijbiomac.2020.08.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/27/2020] [Accepted: 08/03/2020] [Indexed: 11/27/2022]
Abstract
The aggregation kinetics of Aβ1-40 peptide was characterized using a synergistic approach by a combination of nuclear magnetic resonance, thioflavin-T fluorescence, transmission electron microscopy and dynamic light scattering. A major finding is the experimental detection of high molecular weight oligomers (HMWO) that converts into fibrils nuclei. Our observations are consistent with a mechanism of Aβ1-40 fibrillogenesis that includes the following key steps: i) slow formation of HMWO (Rh ~ 20 nm); ii) conversion of the HMWO into more compact Rh ~ 10 nm fibrils nuclei; iii) fast formation of additional fibrils nuclei through fibril surface catalysed processes; and iv) growth of fibrils by addition of soluble Aβ species. Moreover, NMR diffusion experiments show that at 37 °C soluble Aβ1-40 remains intrinsically disordered and mostly in monomeric form despite evidences of the presence of dimers and/or other small oligomers. A mathematical model is proposed to simulate the aggregation kinetics of Aβ1-40.
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Affiliation(s)
- José P Leite
- i3S - Instituto de Investigação e Inovação em Saúde, Rua Alfredo Allen, 208, Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Rua Alfredo Allen, 208, Porto, Portugal; ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Rua de Jorge Viterbo Ferreira 228, Porto, Portugal
| | - Ana Gimeno
- CIC bioGUNE, Bizkaia Technology Park, Building 801A, 48170 Derio, Spain
| | - Pablo Taboada
- Colloids and Polymers Physics Group, Particle Physics Department, 15782 Campus Vida, Universidade de Santiago de Compostela, Spain
| | - Jesús J Jiménez-Barbero
- CIC bioGUNE, Bizkaia Technology Park, Building 801A, 48170 Derio, Spain; Ikerbasque, Basque Foundation for Science, Maria Diaz de Haro 13, 48009 Bilbao, Spain; Department of Organic Chemistry II, Faculty of Science & Technology, University of the Basque Country, 48940 Leioa, Bizkaia, Spain
| | - Luís Gales
- i3S - Instituto de Investigação e Inovação em Saúde, Rua Alfredo Allen, 208, Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Rua Alfredo Allen, 208, Porto, Portugal; ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Rua de Jorge Viterbo Ferreira 228, Porto, Portugal.
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128
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Köhn B, Kovermann M. All atom insights into the impact of crowded environments on protein stability by NMR spectroscopy. Nat Commun 2020; 11:5760. [PMID: 33188202 PMCID: PMC7666220 DOI: 10.1038/s41467-020-19616-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 10/23/2020] [Indexed: 01/16/2023] Open
Abstract
The high density of macromolecules affecting proteins due to volume exclusion has been discussed in theory but numerous in vivo experiments cannot be sufficiently understood taking only pure entropic stabilization into account. Here, we show that the thermodynamic stability of a beta barrel protein increases equally at all atomic levels comparing crowded environments with dilute conditions by applying multidimensional high-resolution NMR spectroscopy in a systematic manner. Different crowding agents evoke a pure stabilization cooperatively and do not disturb the surface or integrity of the protein fold. The here developed methodology provides a solid base that can be easily expanded to incorporate e.g. binding partners to recognize functional consequences of crowded conditions. Our results are relevant to research projects targeting soluble proteins in vivo as it can be anticipated that their thermodynamic stability increase comparably and has consequently to be taken into account to coherently understand intracellular processes.
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Affiliation(s)
- Birgit Köhn
- Department of Chemistry, University of Konstanz, Universitätsstrasse. 10, 78457, Konstanz, Germany
- Konstanz Research School Chemical Biology KoRS-CB, University of Konstanz, Universitätsstrasse. 10, 78457, Konstanz, Germany
| | - Michael Kovermann
- Department of Chemistry, University of Konstanz, Universitätsstrasse. 10, 78457, Konstanz, Germany.
- Konstanz Research School Chemical Biology KoRS-CB, University of Konstanz, Universitätsstrasse. 10, 78457, Konstanz, Germany.
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129
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Sottini A, Borgia A, Borgia MB, Bugge K, Nettels D, Chowdhury A, Heidarsson PO, Zosel F, Best RB, Kragelund BB, Schuler B. Polyelectrolyte interactions enable rapid association and dissociation in high-affinity disordered protein complexes. Nat Commun 2020; 11:5736. [PMID: 33184256 PMCID: PMC7661507 DOI: 10.1038/s41467-020-18859-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/14/2020] [Indexed: 02/07/2023] Open
Abstract
Highly charged intrinsically disordered proteins can form complexes with very high affinity in which both binding partners fully retain their disorder and dynamics, exemplified by the positively charged linker histone H1.0 and its chaperone, the negatively charged prothymosin α. Their interaction exhibits another surprising feature: The association/dissociation kinetics switch from slow two-state-like exchange at low protein concentrations to fast exchange at higher, physiologically relevant concentrations. Here we show that this change in mechanism can be explained by the formation of transient ternary complexes favored at high protein concentrations that accelerate the exchange between bound and unbound populations by orders of magnitude. Molecular simulations show how the extreme disorder in such polyelectrolyte complexes facilitates (i) diffusion-limited binding, (ii) transient ternary complex formation, and (iii) fast exchange of monomers by competitive substitution, which together enable rapid kinetics. Biological polyelectrolytes thus have the potential to keep regulatory networks highly responsive even for interactions with extremely high affinities.
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Affiliation(s)
- Andrea Sottini
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Alessandro Borgia
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Madeleine B Borgia
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Katrine Bugge
- Structural Biology and NMR Laboratory (SBiNLab) and REPIN, Department of Biology, Ole Maaloes Vej 5, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Daniel Nettels
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Aritra Chowdhury
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Pétur O Heidarsson
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
- Department of Biochemistry, Science Institute, University of Iceland, Dunhagi 3, 107, Reykjavík, Iceland
| | - Franziska Zosel
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
- Novo Nordisk A/S, Novo Nordisk Park, 2760, Måløv, Denmark
| | - Robert B Best
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA.
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory (SBiNLab) and REPIN, Department of Biology, Ole Maaloes Vej 5, University of Copenhagen, 2200, Copenhagen, Denmark.
| | - Benjamin Schuler
- Department of Biochemistry, University of Zurich, Zurich, Switzerland.
- Department of Physics, University of Zurich, Zurich, Switzerland.
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130
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Siu HW, Heck B, Kovermann M, Hauser K. Template-assisted design of monomeric polyQ models to unravel the unique role of glutamine side chains in disease-related aggregation. Chem Sci 2020; 12:412-426. [PMID: 33552461 PMCID: PMC7863018 DOI: 10.1039/d0sc05299j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 10/28/2020] [Indexed: 01/28/2023] Open
Abstract
PolyQ model peptides reveal the effect of individual glutamine side chains on fibril formation.
Expanded polyglutamine (polyQ) sequences cause numerous neurodegenerative diseases which are accompanied by the formation of polyQ fibrils. The unique role of glutamines in the aggregation onset is undoubtedly accepted and a lot structural data of the fibrils have been acquired, however side-chain specific structural dynamics inducing oligomerization are not well understood yet. To analyze spectroscopically the nucleation process, we designed various template-assisted glutamine-rich β-hairpin monomers mimicking the structural motif of a polyQ fibril. In a top-down strategy, we use a template which forms a well-defined stable hairpin in solution, insert polyQ-rich sequences into each strand and monitor the effects of individual glutamines by NMR, CD and IR spectroscopic approaches. The design was further advanced by alternating glutamines with other amino acids (T, W, E, K), thereby enhancing the solubility and increasing the number of cross-strand interacting glutamine side chains. Our spectroscopic studies reveal a decreasing hairpin stability with increased glutamine content and demonstrate the enormous impact of only a few glutamines – far below the disease threshold – to destabilize structure. Furthermore, we could access sub-ms conformational dynamics of monomeric polyQ-rich peptides by laser-excited temperature-jump IR spectroscopy. Both, the increased number of interacting glutamines and higher concentrations are key parameters to induce oligomerization. Concentration-dependent time-resolved IR measurements indicate an additional slower kinetic phase upon oligomer formation. The here presented peptide models enable spectroscopic molecular analyses to distinguish between monomer and oligomer dynamics in the early steps of polyQ fibril formation and in a side-chain specific manner.
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Affiliation(s)
- Ho-Wah Siu
- Department of Chemistry , University of Konstanz , 78457 Konstanz , Germany . ;
| | - Benjamin Heck
- Department of Chemistry , University of Konstanz , 78457 Konstanz , Germany . ;
| | - Michael Kovermann
- Department of Chemistry , University of Konstanz , 78457 Konstanz , Germany . ;
| | - Karin Hauser
- Department of Chemistry , University of Konstanz , 78457 Konstanz , Germany . ;
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131
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O'Neill Moore S, Grubb TJ, Kothapalli CR. Insights into the biophysical forces between proteins involved in elastic fiber assembly. J Mater Chem B 2020; 8:9239-9250. [PMID: 32966543 DOI: 10.1039/d0tb01591a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Elastogenesis is a complex process beginning with transcription, translation, and extracellular release of precursor proteins leading to crosslinking, deposition, and assembly of ubiquitous elastic fibers. While the biochemical pathways by which elastic fibers are assembled are known, the biophysical forces mediating the interactions between the constituent proteins are unknown. Using atomic force microscopy, we quantified the adhesive forces among the elastic fiber components, primarily between tropoelastin, elastin binding protein (EBP), fibrillin-1, fibulin-5, and lysyl oxidase-like 2 (LOXL2). The adhesive forces between tropoelastin and other tissue-derived proteins such as insoluble elastin, laminin, and type I collagens were also assessed. The adhesive forces between tropoelastin and laminin were strong (1767 ± 126 pN; p < 10-5vs. all others), followed by forces (≥200 pN) between tropoelastin and human collagen, mature elastin, or tropoelastin. The adhesive forces between tropoelastin and rat collagen, EBP, fibrillin-1, fibulin-5, and LOXL2 coated on fibrillin-1 were in the range of 100-200 pN. The forces between tropoelastin and LOXL2, LOXL2 and fibrillin-1, LOXL2 and fibulin-5, and fibrillin-1 and fibulin-5 were less than 100 pN. Introducing LOXL2 decreased the adhesive forces between the tropoelastin monomers by ∼100 pN. The retraction phase of force-deflection curves was fitted to the worm-like chain model to calculate the rigidity and flexibility of these proteins as they unfolded. The results provided insights into how each constituent's stretching under deformation contributes to structural and mechanical characteristics of these fibers and to elastic fiber assembly.
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Affiliation(s)
- Sean O'Neill Moore
- Department of Chemical and Biomedical Engineering, FH 460, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA.
| | - Tyler Jacob Grubb
- Department of Chemical and Biomedical Engineering, FH 460, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA.
| | - Chandrasekhar R Kothapalli
- Department of Chemical and Biomedical Engineering, FH 460, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA.
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132
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Neira JL, Rizzuti B, Jiménez-Alesanco A, Abián O, Velázquez-Campoy A, Iovanna JL. The Paralogue of the Intrinsically Disordered Nuclear Protein 1 Has a Nuclear Localization Sequence that Binds to Human Importin α3. Int J Mol Sci 2020; 21:ijms21197428. [PMID: 33050086 PMCID: PMC7583046 DOI: 10.3390/ijms21197428] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 09/28/2020] [Accepted: 10/03/2020] [Indexed: 02/07/2023] Open
Abstract
Numerous carrier proteins intervene in protein transport from the cytoplasm to the nucleus in eukaryotic cells. One of those is importin α, with several human isoforms; among them, importin α3 (Impα3) features a particularly high flexibility. The protein NUPR1L is an intrinsically disordered protein (IDP), evolved as a paralogue of nuclear protein 1 (NUPR1), which is involved in chromatin remodeling and DNA repair. It is predicted that NUPR1L has a nuclear localization sequence (NLS) from residues Arg51 to Gln74, in order to allow for nuclear translocation. We studied in this work the ability of intact NUPR1L to bind Impα3 and its depleted species, ∆Impα3, without the importin binding domain (IBB), using fluorescence, isothermal titration calorimetry (ITC), circular dichroism (CD), nuclear magnetic resonance (NMR), and molecular docking techniques. Furthermore, the binding of the peptide matching the isolated NLS region of NUPR1L (NLS-NUPR1L) was also studied using the same methods. Our results show that NUPR1L was bound to Imp α3 with a low micromolar affinity (~5 μM). Furthermore, a similar affinity value was observed for the binding of NLS-NUPR1L. These findings indicate that the NLS region, which was unfolded in isolation in solution, was essentially responsible for the binding of NUPR1L to both importin species. This result was also confirmed by our in silico modeling. The binding reaction of NLS-NUPR1L to ∆Impα3 showed a larger affinity (i.e., lower dissociation constant) compared with that of Impα3, confirming that the IBB could act as an auto-inhibition region of Impα3. Taken together, our findings pinpoint the theoretical predictions of the NLS region in NUPR1L and, more importantly, suggest that this IDP relies on an importin for its nuclear translocation.
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Affiliation(s)
- José L. Neira
- IDIBE, Universidad Miguel Hernández, 03202 Elche (Alicante), Spain
- Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain; (A.J.-A.); (O.A.); (A.V.-C.)
- Correspondence: (J.L.N.); (J.L.I.); Tel.: +34-966-65-8475 (J.L.N.); +33(0)491-82-8803 (J.L.I.)
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, Via P. Bucci, Cubo 31 C, Arcavacata di Rende, 87036 Cosenza, Italy;
| | - Ana Jiménez-Alesanco
- Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain; (A.J.-A.); (O.A.); (A.V.-C.)
| | - Olga Abián
- Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain; (A.J.-A.); (O.A.); (A.V.-C.)
- Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Instituto Aragonés de Ciencias de la Salud (IACS), 50009 Zaragoza, Spain
| | - Adrián Velázquez-Campoy
- Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain; (A.J.-A.); (O.A.); (A.V.-C.)
- Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Fundacion ARAID, Gobierno de Aragon, 50009 Zaragoza, Spain
| | - Juan L. Iovanna
- Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, CNRS UMR 7258, Aix-Marseille Université and Institut Paoli-Calmettes, Parc Scientifique et Technologique de Luminy, 163 Avenue de Luminy, 13288 Marseille, France
- Correspondence: (J.L.N.); (J.L.I.); Tel.: +34-966-65-8475 (J.L.N.); +33(0)491-82-8803 (J.L.I.)
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Rezvani Boroujeni E, Hosseini SM, Fani G, Cecchi C, Chiti F. Soluble Prion Peptide 107-120 Protects Neuroblastoma SH-SY5Y Cells against Oligomers Associated with Alzheimer's Disease. Int J Mol Sci 2020; 21:E7273. [PMID: 33019683 PMCID: PMC7582777 DOI: 10.3390/ijms21197273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/27/2020] [Accepted: 09/28/2020] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia and soluble amyloid β (Aβ) oligomers are thought to play a critical role in AD pathogenesis. Cellular prion protein (PrPC) is a high-affinity receptor for Aβ oligomers and mediates some of their toxic effects. The N-terminal region of PrPC can interact with Aβ, particularly the region encompassing residues 95-110. In this study, we identified a soluble and unstructured prion-derived peptide (PrP107-120) that is external to this region of the sequence and was found to successfully reduce the mitochondrial impairment, intracellular ROS generation and cytosolic Ca2+ uptake induced by oligomeric Aβ42 ADDLs in neuroblastoma SH-SY5Y cells. PrP107-120 was also found to rescue SH-SY5Y cells from Aβ42 ADDL internalization. The peptide did not change the structure and aggregation pathway of Aβ42 ADDLs, did not show co-localization with Aβ42 ADDLs in the cells and showed a partial colocalization with the endogenous cellular PrPC. As a sequence region that is not involved in Aβ binding but in PrP self-recognition, the peptide was suggested to protect against the toxicity of Aβ42 oligomers by interfering with cellular PrPC and/or activating a signaling that protected the cells. These results strongly suggest that PrP107-120 has therapeutic potential for AD.
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Affiliation(s)
- Elham Rezvani Boroujeni
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Science and Biotechnology, Shahid Beheshti University, Tehran 1983969411, Iran;
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale G.B Morgagni 50, 50134 Florence, Italy; (G.F.); (C.C.)
| | - Seyed Masoud Hosseini
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Science and Biotechnology, Shahid Beheshti University, Tehran 1983969411, Iran;
| | - Giulia Fani
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale G.B Morgagni 50, 50134 Florence, Italy; (G.F.); (C.C.)
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale G.B Morgagni 50, 50134 Florence, Italy; (G.F.); (C.C.)
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale G.B Morgagni 50, 50134 Florence, Italy; (G.F.); (C.C.)
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A Phosphorylation-Induced Switch in the Nuclear Localization Sequence of the Intrinsically Disordered NUPR1 Hampers Binding to Importin. Biomolecules 2020; 10:biom10091313. [PMID: 32933064 PMCID: PMC7565984 DOI: 10.3390/biom10091313] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 09/05/2020] [Accepted: 09/09/2020] [Indexed: 12/24/2022] Open
Abstract
Several carrier proteins are involved in protein transport from the cytoplasm to the nucleus in eukaryotic cells. One of those is importin α, of which there are several human isoforms; among them, importin α3 (Impα3) has a high flexibility. The protein NUPR1, a nuclear protein involved in the cell-stress response and cell cycle regulation, is an intrinsically disordered protein (IDP) that has a nuclear localization sequence (NLS) to allow for nuclear translocation. NUPR1 does localize through the whole cell. In this work, we studied the affinity of the isolated wild-type NLS region (residues 54–74) of NUPR1 towards Impα3 and several mutants of the NLS region by using several biophysical techniques and molecular docking approaches. The NLS region of NUPR1 interacted with Impα3, opening the way to model the nuclear translocation of disordered proteins. All the isolated NLS peptides were disordered. They bound to Impα3 with low micromolar affinity (1.7–27 μM). Binding was hampered by removal of either Lys65 or Lys69 residues, indicating that positive charges were important; furthermore, binding decreased when Thr68 was phosphorylated. The peptide phosphorylated at Thr68, as well as four phospho-mimetic peptides (all containing the Thr68Glu mutation), showed the presence of a sequential NN(i,i + 1) nuclear Overhauser effect (NOE) in the 2D-1H-NMR (two-dimensional–proton NMR) spectra, indicating the presence of turn-like conformations. Thus, the phosphorylation of Thr68 modulates the binding of NUPR1 to Impα3 by a conformational, entropy-driven switch from a random-coil conformation to a turn-like structure.
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135
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Pabbathi A, Samanta A. On the Stability and Conformational Dynamics of Cytochrome c in Ammonium Ionic Liquids. J Phys Chem B 2020; 124:8132-8140. [PMID: 32830967 DOI: 10.1021/acs.jpcb.0c05633] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Owing to their potential applications in the extraction, purification, and preservation of biomolecules and biocatalysis, ionic liquids (ILs) have gained great attention in biotechnology. Although it is known that the structure and dynamics of proteins in ILs depend on the nature of both proteins and ILs, the biophysical mechanism governing the protein-IL interaction, which determines the stability of proteins or the activity of an enzyme in these nonconventional media, is yet to be understood clearly. Herein, we study the effect of two ammonium ILs, triethylammonium dihydrogen phosphate (TEAP) and tributylammonium dihydrogen phosphate (TBAP), on the stability and conformational dynamics of cytochrome c (Cyt c) in its native and unfolded states, employing primarily the single molecule-based fluorescence correlation spectroscopy (FCS) technique. The results show that the native structure of Cyt c is not significantly altered by TEAP, but the tertiary structure is perturbed to a great extent by TBAP, which comprises a longer alkyl chain. Fluctuations of the fluorescence intensity of Alexa488 dye-labeled Cyt c in FCS measurements reveal conformational dynamics (67 ± 10 μs) in the native state of Cyt c that is accelerated in the presence of both ILs but not affected when Cyt c is in its unfolded state. The present findings demonstrate how the stability of this protein can be modulated by using ammonium ILs of different alkyl chain lengths.
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Affiliation(s)
- Ashok Pabbathi
- School of Chemistry, University of Hyderabad, Hyderabad 500046, India
| | - Anunay Samanta
- School of Chemistry, University of Hyderabad, Hyderabad 500046, India
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Insight into the Folding and Dimerization Mechanisms of the N-Terminal Domain from Human TDP-43. Int J Mol Sci 2020; 21:ijms21176259. [PMID: 32872449 PMCID: PMC7504384 DOI: 10.3390/ijms21176259] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 08/21/2020] [Accepted: 08/25/2020] [Indexed: 02/06/2023] Open
Abstract
TAR DNA-binding protein 43 (TDP-43) is a 414-residue long nuclear protein whose deposition into intraneuronal insoluble inclusions has been associated with the onset of amyotrophic lateral sclerosis (ALS) and other diseases. This protein is physiologically a homodimer, and dimerization occurs through the N-terminal domain (NTD), with a mechanism on which a full consensus has not yet been reached. Furthermore, it has been proposed that this domain is able to affect the formation of higher molecular weight assemblies. Here, we purified this domain and carried out an unprecedented characterization of its folding/dimerization processes in solution. Exploiting a battery of biophysical approaches, ranging from FRET to folding kinetics, we identified a head-to-tail arrangement of the monomers within the dimer. We found that folding of NTD proceeds through the formation of a number of conformational states and two parallel pathways, while a subset of molecules refold slower, due to proline isomerism. The folded state appears to be inherently prone to form high molecular weight assemblies. Taken together, our results indicate that NTD is inherently plastic and prone to populate different conformations and dimeric/multimeric states, a structural feature that may enable this domain to control the assembly state of TDP-43.
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137
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Improved Production and Biophysical Analysis of Recombinant Silicatein-α. Biomolecules 2020; 10:biom10091209. [PMID: 32825281 PMCID: PMC7565869 DOI: 10.3390/biom10091209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/12/2020] [Accepted: 08/17/2020] [Indexed: 11/16/2022] Open
Abstract
Silicatein-α is a hydrolase found in siliceous sea sponges with a unique ability to condense and hydrolyse silicon–oxygen bonds. The enzyme is thus of interest from the perspective of its unusual enzymology, and for potential applications in the sustainable synthesis of siloxane-containing compounds. However, research into this enzyme has previously been hindered by the tendency of silicatein-α towards aggregation and insolubility. Herein, we report the development of an improved method for the production of a trigger factor-silicatein fusion protein by switching the previous hexahistidine tag for a Strep-II tag, resulting in 244-fold improvement in protein yield compared to previous methods. Light scattering and thermal denaturation analyses show that under the best storage conditions, although oligomerisation is never entirely abolished, these nanoscale aggregates of the Strep-tagged protein exhibit improved colloidal stability and solubility. Enzymatic assays show that the Strep-tagged protein retains catalytic competency, but exhibits lower activity compared to the His6-tagged protein. These results suggest that the hexahistidine tag is capable of non-specific catalysis through their imidazole side chains, highlighting the importance of careful consideration when selecting a purification tag. Overall, the Strep-tagged fusion protein reported here can be produced to a higher yield, exhibits greater stability, and allows the native catalytic properties of this protein to be assessed.
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138
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Skaanning LK, Santoro A, Skamris T, Martinsen JH, D’Ursi AM, Bucciarelli S, Vestergaard B, Bugge K, Langkilde AE, Kragelund BB. The Non-Fibrillating N-Terminal of α-Synuclein Binds and Co-Fibrillates with Heparin. Biomolecules 2020; 10:E1192. [PMID: 32824376 PMCID: PMC7464290 DOI: 10.3390/biom10081192] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/12/2020] [Accepted: 08/14/2020] [Indexed: 01/16/2023] Open
Abstract
The intrinsically disordered protein α-synuclein (aSN) is, in its fibrillated state, the main component of Lewy bodies-hallmarks of Parkinson's disease. Additional Lewy body components include glycosaminoglycans, including heparan sulfate proteoglycans. In humans, heparan sulfate has, in an age-dependent manner, shown increased levels of sulfation. Heparin, a highly sulfated glycosaminoglycan, is a relevant mimic for mature heparan sulfate and has been shown to influence aSN fibrillation. Here, we decompose the underlying properties of the interaction between heparin and aSN and the effect of heparin on fibrillation. Via the isolation of the first 61 residues of aSN, which lacked intrinsic fibrillation propensity, fibrillation could be induced by heparin, and access to the initial steps in fibrillation was possible. Here, structural changes with shifts from disorder via type I β-turns to β-sheets were revealed, correlating with an increase in the aSN1-61/heparin molar ratio. Fluorescence microscopy revealed that heparin and aSN1-61 co-exist in the final fibrils. We conclude that heparin can induce the fibrillation of aSN1-61, through binding to the N-terminal with an affinity that is higher in the truncated form of aSN. It does so by specifically modulating the structure of aSN via the formation of type I β-turn structures likely critical for triggering aSN fibrillation.
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Affiliation(s)
- Line K. Skaanning
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark; (L.K.S.); (T.S.); (J.H.M.); (S.B.); (B.V.)
| | - Angelo Santoro
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes vej 5, 2200 Copenhagen N, Denmark; (A.S.); (K.B.)
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy;
| | - Thomas Skamris
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark; (L.K.S.); (T.S.); (J.H.M.); (S.B.); (B.V.)
| | - Jacob Hertz Martinsen
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark; (L.K.S.); (T.S.); (J.H.M.); (S.B.); (B.V.)
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes vej 5, 2200 Copenhagen N, Denmark; (A.S.); (K.B.)
| | - Anna Maria D’Ursi
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy;
| | - Saskia Bucciarelli
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark; (L.K.S.); (T.S.); (J.H.M.); (S.B.); (B.V.)
| | - Bente Vestergaard
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark; (L.K.S.); (T.S.); (J.H.M.); (S.B.); (B.V.)
| | - Katrine Bugge
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes vej 5, 2200 Copenhagen N, Denmark; (A.S.); (K.B.)
| | - Annette Eva Langkilde
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark; (L.K.S.); (T.S.); (J.H.M.); (S.B.); (B.V.)
| | - Birthe B. Kragelund
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes vej 5, 2200 Copenhagen N, Denmark; (A.S.); (K.B.)
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139
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Martin EW, Hopkins JB, Mittag T. Small-angle X-ray scattering experiments of monodisperse intrinsically disordered protein samples close to the solubility limit. Methods Enzymol 2020; 646:185-222. [PMID: 33453925 PMCID: PMC8370720 DOI: 10.1016/bs.mie.2020.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The condensation of biomolecules into biomolecular condensates via liquid-liquid phase separation (LLPS) is a ubiquitous mechanism that drives cellular organization. To enable these functions, biomolecules have evolved to drive LLPS and facilitate partitioning into biomolecular condensates. Determining the molecular features of proteins that encode LLPS will provide critical insights into a plethora of biological processes. Problematically, probing biomolecular dense phases directly is often technologically difficult or impossible. By capitalizing on the symmetry between the conformational behavior of biomolecules in dilute solution and dense phases, it is possible to infer details critical to phase separation by precise measurements of the dilute phase thus circumventing complicated characterization of dense phases. The symmetry between dilute and dense phases is found in the size and shape of the conformational ensemble of a biomolecule-parameters that small-angle X-ray scattering (SAXS) is ideally suited to probe. Recent technological advances have made it possible to accurately characterize samples of intrinsically disordered protein regions at low enough concentration to avoid interference from intermolecular attraction, oligomerization or aggregation, all of which were previously roadblocks to characterizing self-assembling proteins. Herein, we describe the pitfalls inherent to measuring such samples, the experimental details required for circumventing these issues and analysis methods that place the results of SAXS measurements into the theoretical framework of LLPS.
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Affiliation(s)
- Erik W Martin
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Jesse B Hopkins
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL, United States
| | - Tanja Mittag
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, United States.
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140
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Palomino-Hernandez O, Buratti FA, Sacco PS, Rossetti G, Carloni P, Fernandez CO. Role of Tyr-39 for the Structural Features of α-Synuclein and for the Interaction with a Strong Modulator of Its Amyloid Assembly. Int J Mol Sci 2020; 21:ijms21145061. [PMID: 32709107 PMCID: PMC7404028 DOI: 10.3390/ijms21145061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/02/2020] [Accepted: 07/13/2020] [Indexed: 12/03/2022] Open
Abstract
Recent studies suggest that Tyr-39 might play a critical role for both the normal function and the pathological dysfunction of α-synuclein (αS), an intrinsically disordered protein involved in Parkinson’s disease. We perform here a comparative analysis between the structural features of human αS and its Y39A, Y39F, and Y39L variants. By the combined application of site-directed mutagenesis, biophysical techniques, and enhanced sampling molecular simulations, we show that removing aromatic functionality at position 39 of monomeric αS leads to protein variants populating more compact conformations, conserving its disordered nature and secondary structure propensities. Contrasting with the subtle changes induced by mutations on the protein structure, removing aromaticity at position 39 impacts strongly on the interaction of αS with the potent amyloid inhibitor phthalocyanine tetrasulfonate (PcTS). Our findings further support the role of Tyr-39 in forming essential inter and intramolecular contacts that might have important repercussions for the function and the dysfunction of αS.
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Affiliation(s)
- Oscar Palomino-Hernandez
- Computational Biomedicine, Institute for Neuroscience and Medicine (INM-9) and Institute for Advanced Simulations (IAS-5), Forschungszentrum Jülich, 52425 Jülich, Germany; (O.P.-H.); (G.R.)
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen, 52425 Aachen, Germany
- Computation-Based Science and Technology Research Center, The Cyprus Institute, 2121 Nicosia, Cyprus
- Institute of Life Science, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Fiamma A. Buratti
- Max Planck Laboratory for Structural Biology, Chemistry and Molecular Biophysics of Rosario (MPLbioR, UNR-MPIbpC) and Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario (IIDEFAR, UNR-CONICET), Universidad Nacional de Rosario, S2002LRK Rosario, Argentina; (F.A.B.); (P.S.S.)
| | - Pamela S. Sacco
- Max Planck Laboratory for Structural Biology, Chemistry and Molecular Biophysics of Rosario (MPLbioR, UNR-MPIbpC) and Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario (IIDEFAR, UNR-CONICET), Universidad Nacional de Rosario, S2002LRK Rosario, Argentina; (F.A.B.); (P.S.S.)
| | - Giulia Rossetti
- Computational Biomedicine, Institute for Neuroscience and Medicine (INM-9) and Institute for Advanced Simulations (IAS-5), Forschungszentrum Jülich, 52425 Jülich, Germany; (O.P.-H.); (G.R.)
- Department of Oncology, Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation University Hospital Aachen, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany
- Jülich Supercomputing Center (JSC), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Paolo Carloni
- Computational Biomedicine, Institute for Neuroscience and Medicine (INM-9) and Institute for Advanced Simulations (IAS-5), Forschungszentrum Jülich, 52425 Jülich, Germany; (O.P.-H.); (G.R.)
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen, 52425 Aachen, Germany
- Institute for Neuroscience and Medicine (INM-11) Forschungszentrum Jülich, 52425 Jülich, Germany
- Correspondence: (P.C.); (C.O.F.); Tel.: +54-341-4237868 (ext. 752) (C.O.F)
| | - Claudio O. Fernandez
- Max Planck Laboratory for Structural Biology, Chemistry and Molecular Biophysics of Rosario (MPLbioR, UNR-MPIbpC) and Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario (IIDEFAR, UNR-CONICET), Universidad Nacional de Rosario, S2002LRK Rosario, Argentina; (F.A.B.); (P.S.S.)
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany
- Correspondence: (P.C.); (C.O.F.); Tel.: +54-341-4237868 (ext. 752) (C.O.F)
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141
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Gawrys-Kopczynska M, Konop M, Maksymiuk K, Kraszewska K, Derzsi L, Sozanski K, Holyst R, Pilz M, Samborowska E, Dobrowolski L, Jaworska K, Mogilnicka I, Ufnal M. TMAO, a seafood-derived molecule, produces diuresis and reduces mortality in heart failure rats. eLife 2020; 9:57028. [PMID: 32510330 PMCID: PMC7334024 DOI: 10.7554/elife.57028] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/07/2020] [Indexed: 02/06/2023] Open
Abstract
Trimethylamine-oxide (TMAO) is present in seafood which is considered to be beneficial for health. Deep-water animals accumulate TMAO to protect proteins, such as lactate dehydrogenase (LDH), against hydrostatic pressure stress (HPS). We hypothesized that TMAO exerts beneficial effects on the circulatory system and protects cardiac LDH exposed to HPS produced by the contracting heart. Male, Sprague-Dawley and Spontaneously-Hypertensive-Heart-Failure (SHHF) rats were treated orally with either water (control) or TMAO. In vitro, LDH with or without TMAO was exposed to HPS and was evaluated using fluorescence correlation spectroscopy. TMAO-treated rats showed higher diuresis and natriuresis, lower arterial pressure and plasma NT-proBNP. Survival in SHHF-control was 66% vs 100% in SHHF-TMAO. In vitro, exposure of LDH to HPS with or without TMAO did not affect protein structure. In conclusion, TMAO reduced mortality in SHHF, which was associated with diuretic, natriuretic and hypotensive effects. HPS and TMAO did not affect LDH protein structure. Heart failure is a common cause of death in industrialized countries with aging populations. Japan, however, has lower rates of heart failure and fewer deaths linked to this disease than the United States or Europe, despite having the highest proportion of elderly people in the world. Dietary differences between these regions may explain the lower rate of heart failure in Japan. The Japanese diet is rich in seafood, which contains nutrients that promote heart health, such as omega-3 fatty acids. Seafood also contains other compounds, including trimethylamine oxide (TMAO). Fish that live in deep waters undergo high pressures, which can damage their proteins, but TMAO seems to protect the proteins from harm. In humans, eating seafood increases TMAO levels in the blood and urine, but it is unclear what effects this has on heart health. Increased levels of TMAO in the blood are associated with cardiovascular diseases, but scientists are not sure whether TMAO itself harms the heart. A toxic byproduct of gut bacteria called TMA is converted in TMAO in the body, so it is possible that TMA rather than TMAO is to blame. To assess the effects of dietary TMAO on heart failure, Gawrys-Kopczynska et al. fed the compound to healthy rats and rats with heart failure for one year. TMAO had no effects on the healthy rats. Of the rats with heart failure that were fed TMAO, all of them survived the year, while one third of rats with heart failure that were not fed TMAO died. TMAO-treated rats with heart failure had lower blood pressure and urinated more than untreated rats with the condition. The experiments suggest that dietary TMAO may mimic the effects of heart failure treatments, which remove excess water and salt and lower pressure on the heart. More studies are needed to confirm whether TMAO has this same effect on humans.
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Affiliation(s)
- Marta Gawrys-Kopczynska
- Department of Experimental Physiology and Pathophysiology, Laboratory of the Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Marek Konop
- Department of Experimental Physiology and Pathophysiology, Laboratory of the Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Klaudia Maksymiuk
- Department of Experimental Physiology and Pathophysiology, Laboratory of the Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Katarzyna Kraszewska
- Department of Experimental Physiology and Pathophysiology, Laboratory of the Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Ladislav Derzsi
- Department of Soft Condensed Matter, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Krzysztof Sozanski
- Department of Soft Condensed Matter, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Robert Holyst
- Department of Soft Condensed Matter, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Marta Pilz
- Department of Soft Condensed Matter, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Emilia Samborowska
- Mass Spectrometry Laboratory, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Leszek Dobrowolski
- Department of Renal and Body Fluid Physiology, M. Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Kinga Jaworska
- Department of Experimental Physiology and Pathophysiology, Laboratory of the Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Izabella Mogilnicka
- Department of Experimental Physiology and Pathophysiology, Laboratory of the Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Marcin Ufnal
- Department of Experimental Physiology and Pathophysiology, Laboratory of the Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
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142
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Al Jawad H, Rabiller-Baudry M, Loulergue P, Bejjani C, Lejeune A, Mawlawi H, Nasser G, Taha S. On the impact of ethanol on the rejection and transfer mechanism during ultrafiltration of a charged macromolecule in water/ethanol. ENVIRONMENTAL TECHNOLOGY 2020; 41:1950-1979. [PMID: 30481129 DOI: 10.1080/09593330.2018.1552724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/30/2018] [Indexed: 06/09/2023]
Abstract
Ultrafiltration (UF) is a sustainable membrane separation technique. It could be useful for the concentration/purification of bio-sourced molecules that are extracted either by pure ethanol or by water/ethanol mixtures. Nevertheless, the process optimization requires an in-depth understanding of the transfer mechanisms of solute through membranes, especially for charged solutes, that are nowadays not sufficiently documented. Previous studies achieved in aqueous media have shown that the rejection of charged solutes by an UF membrane involves at least three mechanisms: convection, diffusion and electrostatic interactions. The present study aims at a systematic analysis of the transfer mechanisms of a model protein (lysozyme) in water/ethanol mixtures (100/0-70/30 v/v) during UF by a zirconia inorganic membrane. The influence of the pH varying in the 4-9 range and of the ionic strength (I) is also discussed. The ionic strength I can be adjusted by addition of an indifferent electrolyte (NaCl) only aiming at the screening of the electrostatic interactions or by addition of a selectively adsorbed electrolyte(KH2PO4) that is able to change the isoelectric pH of the protein and thus to modulate the electrostatic interactions in a different way when compared to NaCl. Of course, both salts have an impact on the protein rejection in UF. The results are analysed using the CDE model previously developed in our group to explain the behaviour of a single protein during UF in water and accounting for convection, diffusion and electrophoretic migration. The applicability of the CDE model in water/ethanol mixtures up to 70/30 v/v is finally shown.
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Affiliation(s)
- H Al Jawad
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), Rennes, France
- Université Libanaise, Laboratoire de Biotechnologie Appliquée: Biomolécules, Biothérapies et Bioprocédés du Centre AZM pour la Recherche en Biotechnologie et ses Applications, Beyrouth, Lebanon
| | - M Rabiller-Baudry
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), Rennes, France
| | - P Loulergue
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), Rennes, France
| | - C Bejjani
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), Rennes, France
- Faculté d'Agronomie et Médecine Vétérinaire, département Sciences et Technologies Agroalimentaires, Université Libanaise, Dekwaneh, Lebanon
| | - A Lejeune
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), Rennes, France
| | - H Mawlawi
- Université Libanaise, Laboratoire de Biotechnologie Appliquée: Biomolécules, Biothérapies et Bioprocédés du Centre AZM pour la Recherche en Biotechnologie et ses Applications, Beyrouth, Lebanon
| | - G Nasser
- Faculté d'Agronomie et Médecine Vétérinaire, département Sciences et Technologies Agroalimentaires, Université Libanaise, Dekwaneh, Lebanon
| | - S Taha
- Université Libanaise, Laboratoire de Biotechnologie Appliquée: Biomolécules, Biothérapies et Bioprocédés du Centre AZM pour la Recherche en Biotechnologie et ses Applications, Beyrouth, Lebanon
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143
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Influence of crowding agents on the dynamics of a multidomain protein in its denatured state: a solvation approach. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2020; 49:289-305. [PMID: 32399581 DOI: 10.1007/s00249-020-01435-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 03/26/2020] [Accepted: 04/28/2020] [Indexed: 01/01/2023]
Abstract
It is now well appreciated that the crowded intracellular environment significantly modulates an array of physiological processes including protein folding-unfolding, aggregation, and dynamics to name a few. In this work we have studied the dynamics of domain I of the protein human serum albumin (HSA) in its urea-induced denatured states, in the presence of a series of commonly used macromolecular crowding agents. HSA was labeled at Cys-34 (a free cysteine) in domain I with the fluorophore 6-bromoacetyl-2-dimethylaminonaphthalene (BADAN) to act as a solvation probe. In partially denatured states (2-6 M urea), lower crowder concentrations (~ < 125 g/L) induced faster dynamics, while the dynamics became slower beyond 150 g/L of crowders. We propose that this apparent switch in dynamics is an evidence of a crossover from soft (enthalpic) to hard-core (entropic) interactions between the protein and crowder molecules. That soft interactions are also important for the crowders used here was further confirmed by the appreciable shift in the wavelength of the emission maximum of BADAN, in particular for PEG8000 and Ficoll 70 at concentrations where the excluded volume effect is not dominant.
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144
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Soranno A. Physical basis of the disorder-order transition. Arch Biochem Biophys 2020; 685:108305. [DOI: 10.1016/j.abb.2020.108305] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 02/10/2020] [Accepted: 02/14/2020] [Indexed: 12/29/2022]
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145
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Alderson TR, Ying J, Bax A, Benesch JLP, Baldwin AJ. Conditional Disorder in Small Heat-shock Proteins. J Mol Biol 2020; 432:3033-3049. [PMID: 32081587 PMCID: PMC7245567 DOI: 10.1016/j.jmb.2020.02.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/27/2020] [Accepted: 02/09/2020] [Indexed: 12/31/2022]
Abstract
Small heat-shock proteins (sHSPs) are molecular chaperones that respond to cellular stresses to combat protein aggregation. HSP27 is a critical human sHSP that forms large, dynamic oligomers whose quaternary structures and chaperone activities depend on environmental factors. Upon exposure to cellular stresses, such as heat shock or acidosis, HSP27 oligomers can dissociate into dimers and monomers, which leads to significantly enhanced chaperone activity. The structured core of the protein, the α-crystallin domain (ACD), forms dimers and can prevent the aggregation of substrate proteins to a similar degree as the full-length protein. When the ACD dimer dissociates into monomers, it partially unfolds and exhibits enhanced activity. Here, we used solution-state NMR spectroscopy to characterize the structure and dynamics of the HSP27 ACD monomer. Web show that the monomer is stabilized at low pH and that its backbone chemical shifts, 15N relaxation rates, and 1H-15N residual dipolar couplings suggest structural changes and rapid motions in the region responsible for dimerization. By analyzing the solvent accessible and buried surface areas of sHSP structures in the context of a database of dimers that are known to dissociate into disordered monomers, we predict that ACD dimers from sHSPs across all kingdoms of life may partially unfold upon dissociation. We propose a general model in which conditional disorder-the partial unfolding of ACDs upon monomerization-is a common mechanism for sHSP activity.
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Affiliation(s)
- T Reid Alderson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK; Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Justin L P Benesch
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
| | - Andrew J Baldwin
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
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146
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Evans R. The interpretation of small molecule diffusion coefficients: Quantitative use of diffusion-ordered NMR spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 117:33-69. [PMID: 32471534 DOI: 10.1016/j.pnmrs.2019.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 11/20/2019] [Accepted: 11/20/2019] [Indexed: 06/11/2023]
Abstract
Measuring accurate molecular self-diffusion coefficients, D, by nuclear magnetic resonance (NMR) techniques has become routine as hardware, software and experimental methodologies have all improved. However, the quantitative interpretation of such data remains difficult, particularly for small molecules. This review article first provides a description of, and explanation for, the failure of the Stokes-Einstein equation to accurately predict small molecule diffusion coefficients, before moving on to three broadly complementary methods for their quantitative interpretation. Two are based on power laws, but differ in the nature of the reference molecules used. The third addresses the uncertainties in the Stokes-Einstein equation directly. For all three methods, a wide range of examples are used to show the range of chemistry to which diffusion NMR can be applied, and how best to implement the different methods to obtain quantitative information from the chemical systems studied.
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Affiliation(s)
- Robert Evans
- Aston Institute of Materials Research, School of Engineering and Applied Science, Aston University, Birmingham B4 7ET, United Kingdom.
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147
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Barulin A, Wenger J. Ultraviolet Photostability Improvement for Autofluorescence Correlation Spectroscopy on Label-Free Proteins. J Phys Chem Lett 2020; 11:2027-2035. [PMID: 32083877 DOI: 10.1021/acs.jpclett.0c00209] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The poor photostability and low brightness of protein autofluorescence have been major limitations preventing the detection of label-free proteins at the single-molecule level. Overcoming these issues, we report here a strategy to promote the photostability of proteins and use their natural tryptophan autofluorescence in the ultraviolet (UV) for fluorescence correlation spectroscopy (FCS). Combining enzymatic oxygen scavengers with antioxidants and triplet-state quenchers greatly promotes the protein photostability, reduces the photobleaching probability, and improves the net autofluorescence detection rate. Our results show that the underlying photochemical concepts initially derived for organic visible fluorescent dyes are quite general. Using this approach, we achieved UV fluorescence correlation spectroscopy on label-free streptavidin proteins containing only 24 tryptophan residues, 6.5× fewer than the current state-of-the-art. This strategy greatly extends the possibility of detecting single label-free proteins with the versatility of single-molecule fluorescence without requiring the presence of a potentially disturbing external fluorescent marker. It also opens new perspectives to improve the UV durability of organic devices.
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Affiliation(s)
- Aleksandr Barulin
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, 13013 Marseille, France
| | - Jérôme Wenger
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, 13013 Marseille, France
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148
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Junod SL, Kelich JM, Ma J, Yang W. Nucleocytoplasmic transport of intrinsically disordered proteins studied by high-speed super-resolution microscopy. Protein Sci 2020; 29:1459-1472. [PMID: 32096308 DOI: 10.1002/pro.3845] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 02/18/2020] [Accepted: 02/18/2020] [Indexed: 11/10/2022]
Abstract
Both natively folded and intrinsically disordered proteins (IDPs) destined for the nucleus need to transport through the nuclear pore complexes (NPCs) in eukaryotic cells. NPCs allow for passive diffusion of small folded proteins while barricading large ones, unless they are facilitated by nuclear transport receptors. However, whether nucleocytoplasmic transport of IDPs would follow these rules remains unknown. By using a high-speed super-resolution fluorescence microscopy, we have measured transport kinetics and 3D spatial locations of transport routes through native NPCs for various IDPs. Our data revealed that the rules executed for folded proteins are not well followed by the IDPs. Instead, both large and small IDPs can passively diffuse through the NPCs. Furthermore, their diffusion efficiencies and routes are differentiated by their content ratio of charged (Ch) and hydrophobic (Hy) amino acids. A Ch/Hy-ratio mechanism was finally suggested for nucleocytoplasmic transport of IDPs.
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Affiliation(s)
- Samuel L Junod
- Department of Biology, Temple University, Philadelphia, Pennsylvania
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149
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Ramanujam V, Alderson TR, Pritišanac I, Ying J, Bax A. Protein structural changes characterized by high-pressure, pulsed field gradient diffusion NMR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 312:106701. [PMID: 32113145 PMCID: PMC7153785 DOI: 10.1016/j.jmr.2020.106701] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 02/16/2020] [Accepted: 02/17/2020] [Indexed: 06/10/2023]
Abstract
Pulsed-field gradient NMR spectroscopy is widely used to measure the translational diffusion and hydrodynamic radius (Rh) of biomolecules in solution. For unfolded proteins, the Rh provides a sensitive reporter on the ensemble-averaged conformation and the extent of polypeptide chain expansion as a function of added denaturant. Hydrostatic pressure is a convenient and reversible alternative to chemical denaturants for the study of protein folding, and enables NMR measurements to be performed on a single sample. While the impact of pressure on the viscosity of water is well known, and our water diffusivity measurements agree closely with theoretical expectations, we find that elevated pressures increase the Rh of dioxane and other small molecules by amounts that correlate with their hydrophobicity, with parallel increases in rotational friction indicated by 13C longitudinal relaxation times. These data point to a tighter coupling with water for hydrophobic surfaces at elevated pressures. Translational diffusion measurement of the unfolded state of a pressure-sensitized ubiquitin mutant (VA2-ubiquitin) as a function of hydrostatic pressure or urea concentration shows that Rh values of both the folded and the unfolded states remain nearly invariant. At ca 23 Å, the Rh of the fully pressure-denatured state is essentially indistinguishable from the urea-denatured state, and close to the value expected for an idealized random coil of 76 residues. The intrinsically disordered protein (IDP) α-synuclein shows slight compaction at pressures above 2 kbar. Diffusion of unfolded ubiquitin and α-synuclein is significantly impacted by sample concentration, indicating that quantitative measurements need to be carried out under dilute conditions.
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Affiliation(s)
- Venkatraman Ramanujam
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60438 Frankfurt am Main, Germany
| | - T Reid Alderson
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60438 Frankfurt am Main, Germany
| | - Iva Pritišanac
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60438 Frankfurt am Main, Germany
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60438 Frankfurt am Main, Germany
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60438 Frankfurt am Main, Germany.
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150
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do Amaral MJ, Araujo TS, Díaz NC, Accornero F, Polycarpo CR, Cordeiro Y, Cabral KM, Almeida MS. Phase Separation and Disorder-to-Order Transition of Human Brain Expressed X-Linked 3 (hBEX3) in the Presence of Small Fragments of tRNA. J Mol Biol 2020; 432:2319-2348. [DOI: 10.1016/j.jmb.2020.02.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 02/10/2020] [Accepted: 02/27/2020] [Indexed: 12/19/2022]
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