1
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Masoumzadeh E, Ying J, Baber JL, Anfinrud P, Bax A. Proline Peptide Bond Isomerization in Ubiquitin Under Folding and Denaturing Conditions by Pressure-Jump NMR. J Mol Biol 2024; 436:168587. [PMID: 38663546 PMCID: PMC11166230 DOI: 10.1016/j.jmb.2024.168587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 05/07/2024]
Abstract
Proline isomerization is widely recognized as a kinetic bottleneck in protein folding, amplified for proteins rich in Pro residues. We introduced repeated hydrostatic pressure jumps between native and pressure-denaturing conditions inside an NMR sample cell to study proline isomerization in the pressure-sensitized L50A ubiquitin mutant. Whereas in two unfolded heptapeptides, X-Pro peptide bonds isomerized ca 1.6-fold faster at 1 bar than at 2.5 kbar, for ubiquitin ca eight-fold faster isomerization was observed for Pro-38 and ca two-fold for Pro-19 and Pro-37 relative to rates measured in the pressure-denatured state. Activation energies for isomerization in pressure-denatured ubiquitin were close to literature values of 20 kcal/mole for denatured polypeptides but showed a substantial drop to 12.7 kcal/mole for Pro-38 at atmospheric pressure. For ubiquitin isomers with a cis E18-P19 peptide bond, the 1-bar NMR spectrum showed sharp resonances with near random coil chemical shifts for the C-terminal half of the protein, characteristic of an unfolded chain, while most of the N-terminal residues were invisible due to exchange broadening, pointing to a metastable partially folded state for this previously recognized 'folding nucleus'. For cis-P37 isomers, a drop in pressure resulted in the rapid loss of nearly all unfolded-state NMR resonances, while the recovery of native state intensity revealed a slow component attributed to cis → trans isomerization of P37. This result implies that the NMR-invisible cis-P37 isomer adopts a molten globule state that encompasses the entire length of the ubiquitin chain, suggestive of a structure that mostly resembles the folded state.
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Affiliation(s)
- Elahe Masoumzadeh
- 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
| | - James L Baber
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Philip Anfinrud
- 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.
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2
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Gelenter MD, Yau WM, Anfinrud PA, Bax A. From Milliseconds to Minutes: Melittin Self-Assembly from Concerted Non-Equilibrium Pressure-Jump and Equilibrium Relaxation Nuclear Magnetic Resonance. J Phys Chem Lett 2024; 15:1930-1935. [PMID: 38346015 PMCID: PMC10896212 DOI: 10.1021/acs.jpclett.3c03563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/25/2024] [Accepted: 01/29/2024] [Indexed: 02/23/2024]
Abstract
Non-equilibrium kinetics techniques like pressure-jump nuclear magnetic resonance (NMR) are powerful in tracking changes in oligomeric populations and are not limited by relaxation rates for the time scales of exchange that can be probed. However, these techniques are less sensitive to minor, transient populations than are Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments. We integrated non-equilibrium pressure-jump and equilibrium CPMG relaxation dispersion data to fully map the kinetic landscape of melittin tetramerization. While monomeric peptides weakly form dimers (Kd,D/M ≈ 26 mM) whose population never exceeds 1.6% at 288 K, dimers associate tightly to form stable tetrameric species (Kd,T/D ≈ 740 nM). Exchange between the monomer and dimer, along with exchange between the dimer and tetramer, occurs on the millisecond time scale. The NMR approach developed herein can be readily applied to studying the folding and misfolding of a wide range of oligomeric assemblies.
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Affiliation(s)
- Martin D Gelenter
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Memorial Drive, Bethesda, Maryland 20892, United States
| | - Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Memorial Drive, Bethesda, Maryland 20892, United States
| | - Philip A Anfinrud
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Memorial Drive, Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Memorial Drive, Bethesda, Maryland 20892, United States
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3
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Papadakis CM, Niebuur BJ, Schulte A. Thermoresponsive Polymers under Pressure with a Focus on Poly( N-isopropylacrylamide) (PNIPAM). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:1-20. [PMID: 38149782 DOI: 10.1021/acs.langmuir.3c02398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Pressure is a key variable in the phase behavior of responsive polymers, both for applications and from a fundamental point of view. In this feature article, we review recent developments, particularly applications of neutron techniques such as small-angle neutron scattering (SANS) and quasi-elastic neutron scattering (QENS), across the temperature-pressure phase diagram. These are complemented by kinetic SANS experiments following pressure jumps. In the prototype system poly(N-isopropylacrylamide) (PNIPAM), QENS revealed the pressure-dependent characteristics of hydration water around the lower critical solution temperature transition. The size, water content, and inner structure of the mesoglobules formed in the two-phase region depend strongly on pressure, as shown by SANS. Beside these changes at the phase transition, the mesoglobule formation at low pressure is determined by kinetic factors, namely the formation of a polymer-rich, rigid shell, which hampers further growth by coalescence. At high pressure, in contrast, the growth proceeds by diffusion-limited coalescence without any kinetic hindrance. The disintegration of the mesoglobules evolves either via chain release from their surface or via swelling, depending on the osmotic pressure of the water. Moreover, we report on the profound influence of pressure on the cononsolvency effect. In the temperature-pressure frame, the one-phase region is hugely expanded upon the addition of the cosolvent methanol. SANS experiments unveil the enthalpic and entropic contributions to the effective Flory-Huggins interaction parameter between the segments and the solvent mixture. QENS experiments demonstrate an increase in polymer associated water with pressure, whereas methanol is released. Correspondingly, the solvent phase becomes enriched in methanol, providing a mechanism for the breakdown of cononsolvency at a high pressure. Finally, we outline future opportunities for high-pressure studies of thermoresponsive polymers, with a focus on neutron methods.
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Affiliation(s)
- Christine M Papadakis
- TUM School of Natural Sciences, Physics Department, Soft Matter Physics Group, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - Bart-Jan Niebuur
- TUM School of Natural Sciences, Physics Department, Soft Matter Physics Group, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - Alfons Schulte
- Department of Physics and College of Optics and Photonics, University of Central Florida, 4111 Libra Drive, Orlando, Florida 32816-2385, United States
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4
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Chiliveri SC, Shen Y, Baber JL, Ying J, Sagar V, Wistow G, Anfinrud P, Bax A. Experimental NOE, Chemical Shift, and Proline Isomerization Data Provide Detailed Insights into Amelotin Oligomerization. J Am Chem Soc 2023; 145:18063-18074. [PMID: 37548612 PMCID: PMC10436275 DOI: 10.1021/jacs.3c05710] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Indexed: 08/08/2023]
Abstract
Amelotin is an intrinsically disordered protein (IDP) rich in Pro residues and is involved in hydroxyapatite mineralization. It rapidly oligomerizes under physiological conditions of pH and pressure but reverts to its monomeric IDP state at elevated pressure. We identified a 105-residue segment of the protein that becomes ordered upon oligomerization, and we used pressure-jump NMR spectroscopy to measure long-range NOE contacts that exist exclusively in the oligomeric NMR-invisible state. The kinetics of oligomerization and dissociation were probed at the residue-specific level, revealing that the oligomerization process is initiated in the C-terminal half of the segment. Using pressure-jump NMR, the degree of order in the oligomer at the sites of Pro residues was probed by monitoring changes in cis/trans equilibria relative to the IDP state after long-term equilibration under oligomerizing conditions. Whereas most Pro residues revert to trans in the oligomeric state, Pro-49 favors a cis configuration and three Pro residues retain an unchanged cis fraction, pointing to their local lack of order in the oligomeric state. NOE contacts and secondary 13C chemical shifts in the oligomeric state indicate the presence of an 11-residue α-helix, preceded by a small intramolecular antiparallel β-sheet, with slower formation of long-range intermolecular interactions to N-terminal residues. Although none of the models generated by AlphaFold2 for the amelotin monomer was consistent with experimental data, subunits of a hexamer generated by AlphaFold-Multimer satisfied intramolecular NOE and chemical shift data and may provide a starting point for developing atomic models for the oligomeric state.
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Affiliation(s)
- Sai Chaitanya Chiliveri
- Laboratory
of Chemical Physics, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - Yang Shen
- Laboratory
of Chemical Physics, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - James L. Baber
- Laboratory
of Chemical Physics, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - Jinfa Ying
- Laboratory
of Chemical Physics, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - Vatsala Sagar
- Section
on Molecular Structure and Function, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Graeme Wistow
- Section
on Molecular Structure and Function, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Philip Anfinrud
- Laboratory
of Chemical Physics, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory
of Chemical Physics, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
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5
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Pastore A, Temussi PA. Unfolding under Pressure: An NMR Perspective. Chembiochem 2023; 24:e202300164. [PMID: 37154795 DOI: 10.1002/cbic.202300164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/06/2023] [Accepted: 05/08/2023] [Indexed: 05/10/2023]
Abstract
This review aims to analyse the role of solution nuclear magnetic resonance spectroscopy in pressure-induced in vitro studies of protein unfolding. Although this transition has been neglected for many years because of technical difficulties, it provides important information about the forces that keep protein structure together. We first analyse what pressure unfolding is, then provide a critical overview of how NMR spectroscopy has contributed to the field and evaluate the observables used in these studies. Finally, we discuss the commonalities and differences between pressure-, cold- and heat-induced unfolding. We conclude that, despite specific peculiarities, in both cold and pressure denaturation the important contribution of the state of hydration of nonpolar side chains is a major factor that determines the pressure dependence of the conformational stability of proteins.
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Affiliation(s)
- Annalisa Pastore
- European Synchrotron Radiation Facilities, 71 Ave des Martyrs, 38000, Grenoble, France
- The Wohl Institute, King's College London, 5 Cutcombe Rd, SE59RT, London, UK
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6
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Krempl C, Wurm JP, Beck Erlach M, Kremer W, Sprangers R. Insights into the Structure of Invisible Conformations of Large Methyl Group Labeled Molecular Machines from High Pressure NMR. J Mol Biol 2023; 435:167922. [PMID: 37330282 DOI: 10.1016/j.jmb.2022.167922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/08/2022] [Accepted: 12/11/2022] [Indexed: 06/19/2023]
Abstract
Most proteins are highly flexible and can adopt conformations that deviate from the energetically most favorable ground state. Structural information on these lowly populated, alternative conformations is often lacking, despite the functional importance of these states. Here, we study the pathway by which the Dcp1:Dcp2 mRNA decapping complex exchanges between an autoinhibited closed and an open conformation. We make use of methyl Carr-Purcell-Meiboom-Gill (CPMG) NMR relaxation dispersion (RD) experiments that report on the population of the sparsely populated open conformation as well as on the exchange rate between the two conformations. To obtain volumetric information on the open conformation as well as on the transition state structure we made use of RD measurements at elevated pressures. We found that the open Dcp1:Dcp2 conformation has a lower molecular volume than the closed conformation and that the transition state is close in volume to the closed state. In the presence of ATP the volume change upon opening of the complex increases and the volume of the transition state lies in-between the volumes of the closed and open state. These findings show that ATP has an effect on the volume changes that are associated with the opening-closing pathway of the complex. Our results highlight the strength of pressure dependent NMR methods to obtain insights into structural features of protein conformations that are not directly observable. As our work makes use of methyl groups as NMR probes we conclude that the applied methodology is also applicable to high molecular weight complexes.
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Affiliation(s)
- Christina Krempl
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Jan Philip Wurm
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Markus Beck Erlach
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Werner Kremer
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Remco Sprangers
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany.
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7
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Negroni M, Kurzbach D. Missing Pieces in Structure Puzzles: How Hyperpolarized NMR Spectroscopy Can Complement Structural Biology and Biochemistry. Chembiochem 2023; 24:e202200703. [PMID: 36624049 DOI: 10.1002/cbic.202200703] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 01/11/2023]
Abstract
Structure determination lies at the heart of many biochemical research programs. However, the "giants": X-ray diffraction, electron microscopy, molecular dynamics simulations, and nuclear magnetic resonance, among others, leave quite a few dark spots on the structural pictures drawn of proteins, nucleic acids, membranes, and other biomacromolecules. For example, structural models under physiological conditions or of short-lived intermediates often remain out of reach of the established experimental methods. This account frames the possibility of including hyperpolarized, that is, dramatically signal-enhanced NMR in existing workflows to fill these spots with detailed depictions. We highlight how integrating methods based on dissolution dynamic nuclear polarization can provide valuable complementary information about formerly inaccessible conformational spaces for many systems. A particular focus will be on hyperpolarized buffers to facilitate the NMR structure determination of challenging systems.
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Affiliation(s)
- Mattia Negroni
- Faculty of Chemistry, Institute of Biological Chemistry, University of Vienna, Währinger Str. 38, 1090, Vienna, Austria
| | - Dennis Kurzbach
- Faculty of Chemistry, Institute of Biological Chemistry, University of Vienna, Währinger Str. 38, 1090, Vienna, Austria
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8
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Reversible switching between two common protein folds in a designed system using only temperature. Proc Natl Acad Sci U S A 2023; 120:e2215418120. [PMID: 36669114 PMCID: PMC9942840 DOI: 10.1073/pnas.2215418120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Naturally occurring metamorphic proteins have the ability to interconvert from one folded state to another through either a limited set of mutations or by way of a change in the local environment. Here, we show in a designed system that it is possible to switch reversibly between two of the most common monomeric folds employing only temperature changes. We demonstrate that a latent 3α state can be unmasked from an α/β-plait topology with a single V90T amino acid substitution, populating both forms simultaneously. The equilibrium between these two states exhibits temperature dependence, such that the 3α state is predominant (>90%) at 5 °C, while the α/β-plait fold is the major species (>90%) at 30 °C. We describe the structure and dynamics of these topologies, how mutational changes affect the temperature dependence, and the energetics and kinetics of interconversion. Additionally, we demonstrate how ligand-binding function can be tightly regulated by large amplitude changes in protein structure over a relatively narrow temperature range that is relevant to biology. The 3α/αβ switch thus represents a potentially useful approach for designing proteins that alter their fold topologies in response to environmental triggers. It may also serve as a model for computational studies of temperature-dependent protein stability and fold switching.
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9
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Zhang S, McCallum SA, Gillilan R, Wang J, Royer CA. High Pressure CPMG and CEST Reveal That Cavity Position Dictates Distinct Dynamic Disorder in the PP32 Repeat Protein. J Phys Chem B 2022; 126:10597-10607. [PMID: 36455152 PMCID: PMC10314987 DOI: 10.1021/acs.jpcb.2c05498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Given the central role of conformational dynamics in protein function, it is essential to characterize the time scales and structures associated with these transitions. High pressure (HP) perturbation favors transitions to excited states because they typically occupy a smaller molar volume, thus facilitating characterization of conformational dynamics. Repeat proteins, with their straightforward architecture, provide good models for probing the sequence dependence of protein conformational dynamics. Investigations of chemical exchange by 15N CPMG relaxation dispersion analysis revealed that introduction of a cavity via substitution of isoleucine 7 by alanine in the N-terminal capping motif of the pp32 leucine-rich repeat protein leads to pressure-dependent conformational exchange detected on the 500 μs-2 ms CPMG time scale. Exchange amplitude decreased from the N- to C-terminus, revealing a gradient of conformational exchange across the protein. In contrast, introduction of a cavity in the central core of pp32 via the L60A mutation led to pressure-induced exchange on a slower (>2 ms) time scale detected by 15N-CEST analysis. Excited state 15N chemical shifts indicated that in the excited state detected by HP CEST, the N-terminal region is mostly unfolded, while the core retains native-like structure. These HP chemical exchange measurements reveal that cavity position dictates exchange on distinct time scales, highlighting the subtle, yet central role of sequence in determining protein conformational dynamics.
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Affiliation(s)
- Siwen Zhang
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy NY USA 12180
| | - Scott A. McCallum
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy NY USA 12180
| | - Richard Gillilan
- Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY USA 14853
| | - Jinqiu Wang
- Graduate Program in Biochemistry and Biophysics, Rensselaer Polytechnic Institute, Troy NY USA 12180
| | - Catherine A. Royer
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy NY USA 12180
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10
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Pastore A, Temussi PA. The Protein Unfolded State: One, No One and One Hundred Thousand. J Am Chem Soc 2022; 144:22352-22357. [PMID: 36450361 DOI: 10.1021/jacs.2c07696] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Many in vitro studies, in which proteins have been unfolded by the action of a variety of physical or chemical agents, have led to the definition of a folded versus an unfolded state and to the question of what is the nature of the unfolded state. The unstructured nature of this state could suggest that "the" unfolded state is a unique entity which holds true for all kinds of unfolding processes. This assumption has to be questioned because the unfolding processes under different stress conditions are dictated by entirely different mechanisms. As a consequence, it can be easily understood that the final state, generically referred to as "the unfolded state", can be completely different for each of the unfolding processes. The present review examines recent data on the characteristics of the unfolded states emerging from experiments under different conditions, focusing specific attention to the level of compaction of the unfolded species.
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Affiliation(s)
- Annalisa Pastore
- UK Dementia Research Institute at the Maurice Wohl Institute of King's College London, London, SE5 9RT, United Kingdom
| | - Piero Andrea Temussi
- UK Dementia Research Institute at the Maurice Wohl Institute of King's College London, London, SE5 9RT, United Kingdom
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11
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Lenard AJ, Mulder FAA, Madl T. Solvent paramagnetic relaxation enhancement as a versatile method for studying structure and dynamics of biomolecular systems. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 132-133:113-139. [PMID: 36496256 DOI: 10.1016/j.pnmrs.2022.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 09/14/2022] [Accepted: 09/15/2022] [Indexed: 06/17/2023]
Abstract
Solvent paramagnetic relaxation enhancement (sPRE) is a versatile nuclear magnetic resonance (NMR)-based method that allows characterization of the structure and dynamics of biomolecular systems through providing quantitative experimental information on solvent accessibility of NMR-active nuclei. Addition of soluble paramagnetic probes to the solution of a biomolecule leads to paramagnetic relaxation enhancement in a concentration-dependent manner. Here we review recent progress in the sPRE-based characterization of structural and dynamic properties of biomolecules and their complexes, and aim to deliver a comprehensive illustration of a growing number of applications of the method to various biological systems. We discuss the physical principles of sPRE measurements and provide an overview of available co-solute paramagnetic probes. We then explore how sPRE, in combination with complementary biophysical techniques, can further advance biomolecular structure determination, identification of interaction surfaces within protein complexes, and probing of conformational changes and low-population transient states, as well as deliver insights into weak, nonspecific, and transient interactions between proteins and co-solutes. In addition, we present examples of how the incorporation of solvent paramagnetic probes can improve the sensitivity of NMR experiments and discuss the prospects of applying sPRE to NMR metabolomics, drug discovery, and the study of intrinsically disordered proteins.
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Affiliation(s)
- Aneta J Lenard
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Ageing, Molecular Biology and Biochemistry, Research Unit Integrative Structural Biology, Medical University of Graz, 8010 Graz, Austria.
| | - Frans A A Mulder
- Interdisciplinary Nanoscience Center and Department of Chemistry, University of Aarhus, DK-8000 Aarhus, Denmark; Institute of Biochemistry, Johannes Kepler Universität Linz, 4040 Linz, Austria.
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Ageing, Molecular Biology and Biochemistry, Research Unit Integrative Structural Biology, Medical University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria.
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12
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Epasto LM, Che K, Kozak F, Selimovic A, Kadeřávek P, Kurzbach D. Toward protein NMR at physiological concentrations by hyperpolarized water-Finding and mapping uncharted conformational spaces. SCIENCE ADVANCES 2022; 8:eabq5179. [PMID: 35930648 PMCID: PMC9355353 DOI: 10.1126/sciadv.abq5179] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a key method for determining the structural dynamics of proteins in their native solution state. However, the low sensitivity of NMR typically necessitates nonphysiologically high sample concentrations, which often limit the relevance of the recorded data. We show how to use hyperpolarized water by dissolution dynamic nuclear polarization (DDNP) to acquire protein spectra at concentrations of 1 μM within seconds and with a high signal-to-noise ratio. The importance of approaching physiological concentrations is demonstrated for the vital MYC-associated factor X, which we show to switch conformations when diluted. While in vitro conditions lead to a population of the well-documented dimer, concentrations lowered by more than two orders of magnitude entail dimer dissociation and formation of a globularly folded monomer. We identified this structure by integrating DDNP with computational techniques to overcome the often-encountered constraint of DDNP of limited structural information provided by the typically detected one-dimensional spectra.
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Affiliation(s)
- Ludovica M. Epasto
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090 Vienna, Austria
| | - Kateryna Che
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090 Vienna, Austria
| | - Fanny Kozak
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090 Vienna, Austria
| | - Albina Selimovic
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090 Vienna, Austria
| | - Pavel Kadeřávek
- Masaryk University, CEITEC, Kamenice 5, 625 00 Brno, Czech Republic
| | - Dennis Kurzbach
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090 Vienna, Austria
- Corresponding author.
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13
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Gołowicz D, Shchukina A, Kazimierczuk K. Enhanced Nuclear Magnetic Resonance Spectroscopy with Isotropic Mixing as a Pseudodimension. Anal Chem 2022; 94:9114-9121. [PMID: 35695926 PMCID: PMC9244872 DOI: 10.1021/acs.analchem.2c01471] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chemical analysis based on liquid-state nuclear magnetic resonance spectroscopy exploits numerous observables, mainly chemical shifts, relaxation rates, and internuclear coupling constants. Regarding the latter, the efficiencies of internuclear coherence transfers may be encoded in spectral peak intensities. The dependencies of these intensities on the experimental parameter that influences the transfer, for example, mixing time, are an important source of structural information. Yet, they are costly to measure and difficult to analyze. Here, we show that peak intensity build-up curves in two-dimensional total correlation spectroscopy (2D TOCSY) experiments may be quickly measured by employing nonuniform sampling and that their analysis can be effective if supported by quantum mechanical calculations. Thus, such curves can be used to form a new, third pseudodimension of the TOCSY spectrum. Similarly to the other two frequency dimensions, this one also resolves ambiguities and provides characteristic information. We show how the approach supports the analysis of a fragment of protein Tau Repeat-4 domain. Yet, its potential applications are far broader, including the analysis of complex mixtures or other polymers.
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Affiliation(s)
- Dariusz Gołowicz
- Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Alexandra Shchukina
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
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14
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Wilson CB, Tycko R. Millisecond Time-Resolved Solid-State NMR Initiated by Rapid Inverse Temperature Jumps. J Am Chem Soc 2022; 144:9920-9925. [PMID: 35617672 DOI: 10.1021/jacs.2c02704] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Elucidation of the detailed mechanisms by which biological macromolecules undergo major structural conversions, such as folding, complex formation, and self-assembly, is a central concern of biophysical chemistry that will benefit from new experimental methods. We describe a simple technique for initiating a structural conversion process by a rapid decrease in the temperature of a solution, i.e., a rapid inverse temperature jump. By pumping solutions through copper capillary tubes that are thermally anchored to heated and cooled blocks, solution temperatures can be switched from 95 to 30 °C (or lower) in about 0.8 ms. For time-resolved solid-state nuclear magnetic resonance (ssNMR), solutions can then be frozen rapidly by spraying into cold isopentane after a variable structural evolution time τe. As an initial demonstration, we use this "inverse T-jump" technique to characterize the kinetics and mechanism by which the 26-residue peptide melittin converts from its primarily disordered, monomeric state at 95 °C to its α-helical, tetrameric state at 30 °C. One- and two-dimensional ssNMR spectra of frozen solutions with various values of τe, recorded at 25 K with signal enhancements from dynamic nuclear polarization, show that both helical secondary structure and intermolecular contacts develop on the same time scale of about 6 ms. The dependences on τe of both intraresidue crosspeak patterns and inter-residue crosspeak volumes in two-dimensional spectra can be fit with a unidirectional dimerization model, consistent with dimerization being the rate-limiting step for melittin tetramer formation.
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Affiliation(s)
- C Blake Wilson
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
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15
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Hilty C, Kurzbach D, Frydman L. Hyperpolarized water as universal sensitivity booster in biomolecular NMR. Nat Protoc 2022; 17:1621-1657. [PMID: 35546640 DOI: 10.1038/s41596-022-00693-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 02/25/2022] [Indexed: 11/09/2022]
Abstract
NMR spectroscopy is the only method to access the structural dynamics of biomolecules at high (atomistic) resolution in their native solution state. However, this method's low sensitivity has two important consequences: (i) typically experiments have to be performed at high concentrations that increase sensitivity but are not physiological, and (ii) signals have to be accumulated over long periods, complicating the determination of interaction kinetics on the order of seconds and impeding studies of unstable systems. Both limitations are of equal, fundamental relevance: non-native conditions are of limited pharmacological relevance, and the function of proteins, enzymes and nucleic acids often relies on their interaction kinetics. To overcome these limitations, we have developed applications that involve 'hyperpolarized water' to boost signal intensities in NMR of proteins and nucleic acids. The technique includes four stages: (i) preparation of the biomolecule in partially deuterated buffers, (ii) preparation of 'hyperpolarized' water featuring enhanced 1H NMR signals via cryogenic dynamic nuclear polarization, (iii) sudden melting of the cryogenic pellet and dissolution of the protein or nucleic acid in the hyperpolarized water (enabling spontaneous exchanges of protons between water and target) and (iv) recording signal-amplified NMR spectra targeting either labile 1H or neighboring 15N/13C nuclei in the biomolecule. Water in the ensuing experiments is used as a universal 'hyperpolarization' agent, rendering the approach versatile and applicable to any biomolecule possessing labile hydrogens. Thus, questions can be addressed, ranging from protein and RNA folding problems to resolving structure-function relationships of intrinsically disordered proteins to investigating membrane interactions.
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Affiliation(s)
- Christian Hilty
- Chemistry Department, Texas A&M University, College Station, TX, USA.
| | - Dennis Kurzbach
- Faculty of Chemistry, Institute for Biological Chemistry, University of Vienna, Vienna, Austria.
| | - Lucio Frydman
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel.
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16
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Ben-Tal Y, Boaler PJ, Dale HJA, Dooley RE, Fohn NA, Gao Y, García-Domínguez A, Grant KM, Hall AMR, Hayes HLD, Kucharski MM, Wei R, Lloyd-Jones GC. Mechanistic analysis by NMR spectroscopy: A users guide. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 129:28-106. [PMID: 35292133 DOI: 10.1016/j.pnmrs.2022.01.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
A 'principles and practice' tutorial-style review of the application of solution-phase NMR in the analysis of the mechanisms of homogeneous organic and organometallic reactions and processes. This review of 345 references summarises why solution-phase NMR spectroscopy is uniquely effective in such studies, allowing non-destructive, quantitative analysis of a wide range of nuclei common to organic and organometallic reactions, providing exquisite structural detail, and using instrumentation that is routinely available in most chemistry research facilities. The review is in two parts. The first comprises an introduction to general techniques and equipment, and guidelines for their selection and application. Topics include practical aspects of the reaction itself, reaction monitoring techniques, NMR data acquisition and processing, analysis of temporal concentration data, NMR titrations, DOSY, and the use of isotopes. The second part comprises a series of 15 Case Studies, each selected to illustrate specific techniques and approaches discussed in the first part, including in situ NMR (1/2H, 10/11B, 13C, 15N, 19F, 29Si, 31P), kinetic and equilibrium isotope effects, isotope entrainment, isotope shifts, isotopes at natural abundance, scalar coupling, kinetic analysis (VTNA, RPKA, simulation, steady-state), stopped-flow NMR, flow NMR, rapid injection NMR, pure shift NMR, dynamic nuclear polarisation, 1H/19F DOSY NMR, and in situ illumination NMR.
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Affiliation(s)
- Yael Ben-Tal
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Patrick J Boaler
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Harvey J A Dale
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Ruth E Dooley
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom; Evotec (UK) Ltd, 114 Innovation Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, United Kingdom
| | - Nicole A Fohn
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Yuan Gao
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Andrés García-Domínguez
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Katie M Grant
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Andrew M R Hall
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Hannah L D Hayes
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Maciej M Kucharski
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Ran Wei
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Guy C Lloyd-Jones
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom.
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17
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Abstract
Proteins have dynamic structures that undergo chain motions on time scales spanning from picoseconds to seconds. Resolving the resultant conformational heterogeneity is essential for gaining accurate insight into fundamental mechanistic aspects of the protein folding reaction. The use of high-resolution structural probes, sensitive to population distributions, has begun to enable the resolution of site-specific conformational heterogeneity at different stages of the folding reaction. Different states populated during protein folding, including the unfolded state, collapsed intermediate states, and even the native state, are found to possess significant conformational heterogeneity. Heterogeneity in protein folding and unfolding reactions originates from the reduced cooperativity of various kinds of physicochemical interactions between various structural elements of a protein, and between a protein and solvent. Heterogeneity may arise because of functional or evolutionary constraints. Conformational substates within the unfolded state and the collapsed intermediates that exchange at rates slower than the subsequent folding steps give rise to heterogeneity on the protein folding pathways. Multiple folding pathways are likely to represent distinct sequences of structure formation. Insight into the nature of the energy barriers separating different conformational states populated during (un)folding can also be obtained by resolving heterogeneity.
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Affiliation(s)
- Sandhya Bhatia
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India.,Indian Institute of Science Education and Research, Pune 411008, India
| | - Jayant B Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India.,Indian Institute of Science Education and Research, Pune 411008, India
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18
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The A39G FF domain folds on a volcano-shaped free energy surface via separate pathways. Proc Natl Acad Sci U S A 2021; 118:2115113118. [PMID: 34764225 DOI: 10.1073/pnas.2115113118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2021] [Indexed: 11/18/2022] Open
Abstract
Conformational dynamics play critical roles in protein folding, misfolding, function, misfunction, and aggregation. While detecting and studying the different conformational states populated by protein molecules on their free energy surfaces (FESs) remain a challenge, NMR spectroscopy has emerged as an invaluable experimental tool to explore the FES of a protein, as conformational dynamics can be probed at atomic resolution over a wide range of timescales. Here, we use chemical exchange saturation transfer (CEST) to detect "invisible" minor states on the energy landscape of the A39G mutant FF domain that exhibited "two-state" folding kinetics in traditional experiments. Although CEST has mostly been limited to studies of processes with rates between ∼5 to 300 s-1 involving sparse states with populations as low as ∼1%, we show that the line broadening that is often associated with minor state dips in CEST profiles can be exploited to inform on additional conformers, with lifetimes an order of magnitude shorter and populations close to 10-fold smaller than what typically is characterized. Our analysis of CEST profiles that exploits the minor state linewidths of the 71-residue A39G FF domain establishes a folding mechanism that can be described in terms of a four-state exchange process between interconverting states spanning over two orders of magnitude in timescale from ∼100 to ∼15,000 μs. A similar folding scheme is established for the wild-type domain as well. The study shows that the folding of this small domain proceeds through a pair of sparse, partially structured intermediates via two discrete pathways on a volcano-shaped FES.
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19
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Waudby C, Christodoulou J. Analysis of conformational exchange processes using methyl-TROSY-based Hahn echo measurements of quadruple-quantum relaxation. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:777-793. [PMID: 37905227 PMCID: PMC10583286 DOI: 10.5194/mr-2-777-2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/14/2021] [Indexed: 11/02/2023]
Abstract
Transverse nuclear spin relaxation is a sensitive probe of chemical exchange on timescales on the order of microseconds to milliseconds. Here we present an experiment for the simultaneous measurement of the relaxation rates of two quadruple-quantum transitions in 13 CH3 -labelled methyl groups. These coherences are protected against relaxation by intra-methyl dipolar interactions and so have unexpectedly long lifetimes within perdeuterated biomacromolecules. However, these coherences also have an order of magnitude higher sensitivity to chemical exchange broadening than lower order coherences and therefore provide ideal probes of dynamic processes. We show that analysis of the static magnetic field dependence of zero-, double- and quadruple-quantum Hahn echo relaxation rates provides a robust indication of chemical exchange and can determine the signed relative magnitudes of proton and carbon chemical shift differences between ground and excited states. We also demonstrate that this analysis can be combined with established Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion measurements, providing improved precision in parameter estimates, particularly in the determination of 1 H chemical shift differences.
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Affiliation(s)
- Christopher A. Waudby
- Institute of Structural and Molecular Biology, University College
London, London, WC1E 6BT, UK
| | - John Christodoulou
- Institute of Structural and Molecular Biology, University College
London, London, WC1E 6BT, UK
- Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, WC1E 7HX, UK
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20
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Kancherla AK, Marincin KA, Mishra SH, Frueh DP. Minimizing Pervasive Artifacts in 4D Covariance Maps for Protein Side Chain NMR Assignments. J Phys Chem A 2021; 125:8313-8323. [PMID: 34510900 PMCID: PMC8480538 DOI: 10.1021/acs.jpca.1c05507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/24/2021] [Indexed: 01/23/2023]
Abstract
Nuclear magnetic resonance (NMR) is a mainstay of biophysical studies that provides atomic level readouts to formulate molecular mechanisms. Side chains are particularly important to derive mechanisms involving proteins as they carry functional groups, but NMR studies of side chains are often limited by challenges in assigning their signals. Here, we designed a novel computational method that combines spectral derivatives and matrix square-rooting to produce reliable 4D covariance maps from routinely acquired 3D spectra and facilitates side chain resonance assignments. Thus, we generate two 4D maps from 3D-HcccoNH and 3D-HCcH-TOCSY spectra that each help overcome signal overlap or sensitivity losses. These 4D maps feature HC-HSQCs of individual side chains that can be paired to assigned backbone amide resonances of individual aliphatic signals, and both are obtained from a single modified covariance calculation. Further, we present 4D maps produced using conventional triple resonance experiments to easily assign asparagine side chain amide resonances. The 4D covariance maps encapsulate the lengthy manual pattern recognition used in traditional assignment methods and distill the information as correlations that can be easily visualized. We showcase the utility of the 4D covariance maps with a 10 kDa peptidyl carrier protein and a 52 kDa cyclization domain from a nonribosomal peptide synthetase.
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Affiliation(s)
- Aswani K. Kancherla
- Department
of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Room 701 Hunterian, Baltimore, Maryland 21205, United States
| | - Kenneth A. Marincin
- Department
of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Room 701 Hunterian, Baltimore, Maryland 21205, United States
| | - Subrata H. Mishra
- Department
of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Room 701 Hunterian, Baltimore, Maryland 21205, United States
| | - Dominique P. Frueh
- Department
of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Room 701 Hunterian, Baltimore, Maryland 21205, United States
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21
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Xu Y, Huang J. Validating the CHARMM36m protein force field with LJ-PME reveals altered hydrogen bonding dynamics under elevated pressures. Commun Chem 2021; 4:99. [PMID: 36697521 PMCID: PMC9814493 DOI: 10.1038/s42004-021-00537-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 06/08/2021] [Indexed: 01/28/2023] Open
Abstract
The pressure-temperature phase diagram is important to our understanding of the physics of biomolecules. Compared to studies on temperature effects, studies of the pressure dependence of protein dynamic are rather limited. Molecular dynamics (MD) simulations with fine-tuned force fields (FFs) offer a powerful tool to explore the influence of thermodynamic conditions on proteins. Here we evaluate the transferability of the CHARMM36m (C36m) protein force field at varied pressures compared with NMR data using ubiquitin as a model protein. The pressure dependences of J couplings for hydrogen bonds and order parameters for internal motion are in good agreement with experiment. We demonstrate that the C36m FF combined with the Lennard-Jones particle-mesh Ewald (LJ-PME) method is suitable for simulations in a wide range of temperature and pressure. As the ubiquitin remains stable up to 2500 bar, we identify the mobility and stability of different hydrogen bonds in response to pressure. Based on those results, C36m is expected to be applied to more proteins in the future to further investigate protein dynamics under elevated pressures.
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Affiliation(s)
- You Xu
- grid.494629.40000 0004 8008 9315Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang China ,Westlake AI Therapeutics Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang China ,grid.494629.40000 0004 8008 9315Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang China
| | - Jing Huang
- grid.494629.40000 0004 8008 9315Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang China ,Westlake AI Therapeutics Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang China ,grid.494629.40000 0004 8008 9315Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang China
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22
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Dreydoppel M, Dorn B, Modig K, Akke M, Weininger U. Transition-State Compressibility and Activation Volume of Transient Protein Conformational Fluctuations. JACS AU 2021; 1:833-842. [PMID: 34467336 PMCID: PMC8395657 DOI: 10.1021/jacsau.1c00062] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Indexed: 06/13/2023]
Abstract
Proteins are dynamic entities that intermittently depart from their ground-state structures and undergo conformational transitions as a critical part of their functions. Central to understanding such transitions are the structural rearrangements along the connecting pathway, where the transition state plays a special role. Using NMR relaxation at variable temperature and pressure to measure aromatic ring flips inside a protein core, we obtain information on the structure and thermodynamics of the transition state. We show that the isothermal compressibility coefficient of the transition state is similar to that of short-chain hydrocarbon liquids, implying extensive local unfolding of the protein. Our results further indicate that the required local volume expansions of the protein can occur not only with a net positive activation volume of the protein, as expected from previous studies, but also with zero activation volume by compaction of remote void volume, when averaged over the ensemble of states.
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Affiliation(s)
- Matthias Dreydoppel
- Institute
of Physics, Biophysics, Martin-Luther-University
Halle-Wittenberg, D-06120 Halle (Saale), Germany
| | - Britta Dorn
- Institute
of Physics, Biophysics, Martin-Luther-University
Halle-Wittenberg, D-06120 Halle (Saale), Germany
| | - Kristofer Modig
- Division
of Biophysical Chemistry, Center for Molecular Protein Science, Department
of Chemistry, Lund University, P.O. Box 124, SE-22100 Lund, Sweden
| | - Mikael Akke
- Division
of Biophysical Chemistry, Center for Molecular Protein Science, Department
of Chemistry, Lund University, P.O. Box 124, SE-22100 Lund, Sweden
| | - Ulrich Weininger
- Institute
of Physics, Biophysics, Martin-Luther-University
Halle-Wittenberg, D-06120 Halle (Saale), Germany
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23
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Pintér G, Hohmann K, Grün J, Wirmer-Bartoschek J, Glaubitz C, Fürtig B, Schwalbe H. Real-time nuclear magnetic resonance spectroscopy in the study of biomolecular kinetics and dynamics. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:291-320. [PMID: 37904763 PMCID: PMC10539803 DOI: 10.5194/mr-2-291-2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/07/2021] [Indexed: 11/01/2023]
Abstract
The review describes the application of nuclear magnetic resonance (NMR) spectroscopy to study kinetics of folding, refolding and aggregation of proteins, RNA and DNA. Time-resolved NMR experiments can be conducted in a reversible or an irreversible manner. In particular, irreversible folding experiments pose large requirements for (i) signal-to-noise due to the time limitations and (ii) synchronising of the refolding steps. Thus, this contribution discusses the application of methods for signal-to-noise increases, including dynamic nuclear polarisation, hyperpolarisation and photo-CIDNP for the study of time-resolved NMR studies. Further, methods are reviewed ranging from pressure and temperature jump, light induction to rapid mixing to induce rapidly non-equilibrium conditions required to initiate folding.
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Affiliation(s)
- György Pintér
- Institute for Organic Chemistry and Chemical Biology, Center for
Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang
Goethe-Universität Frankfurt, Frankfurt 60438, Germany
| | - Katharina F. Hohmann
- Institute for Organic Chemistry and Chemical Biology, Center for
Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang
Goethe-Universität Frankfurt, Frankfurt 60438, Germany
| | - J. Tassilo Grün
- Institute for Organic Chemistry and Chemical Biology, Center for
Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang
Goethe-Universität Frankfurt, Frankfurt 60438, Germany
| | - Julia Wirmer-Bartoschek
- Institute for Organic Chemistry and Chemical Biology, Center for
Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang
Goethe-Universität Frankfurt, Frankfurt 60438, Germany
| | - Clemens Glaubitz
- Institute for Biophysical Chemistry, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt 60438, Germany
| | - Boris Fürtig
- Institute for Organic Chemistry and Chemical Biology, Center for
Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang
Goethe-Universität Frankfurt, Frankfurt 60438, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Center for
Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang
Goethe-Universität Frankfurt, Frankfurt 60438, Germany
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24
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Yan S, Liu K, Mu L, Liu J, Tang W, Liu B. Research and application of hydrostatic high pressure in tumor vaccines (Review). Oncol Rep 2021; 45:75. [PMID: 33760193 PMCID: PMC8020208 DOI: 10.3892/or.2021.8026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 03/05/2021] [Indexed: 11/29/2022] Open
Abstract
It is well known that hydrostatic pressure (HP) is a physical parameter that is now regarded as an important variable for life. High hydrostatic pressure (HHP) technology has influenced biological systems for more than 100 years. Food and bioscience researchers have shown great interest in HHP technology over the past few decades. The development of knowledge related to this area can better facilitate the application of HHP in the life sciences. Furthermore, new applications for HHP may come from these current studies, particularly in tumor vaccines. Currently, cancer recurrence and metastasis continue to pose a serious threat to human health. The limited efficacy of conventional treatments has led to the need for breakthroughs in immunotherapy and other related areas. Research into tumor vaccines is providing new insights for cancer treatment. The purpose of this review is to present the main findings reported thus far in the relevant scientific literature, focusing on knowledge related to HHP technology and tumor vaccines, and to demonstrate the potential of applying HHP technology to tumor vaccine development.
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Affiliation(s)
- Shuai Yan
- Department of Operating Room, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Kai Liu
- Department of Hand and Foot Surgery, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Lin Mu
- Department of Radiology, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Jianfeng Liu
- Department of Hand and Foot Surgery, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Wan Tang
- Department of Operating Room, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Bin Liu
- Department of Hand and Foot Surgery, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
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25
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Ando N, Barquera B, Bartlett DH, Boyd E, Burnim AA, Byer AS, Colman D, Gillilan RE, Gruebele M, Makhatadze G, Royer CA, Shock E, Wand AJ, Watkins MB. The Molecular Basis for Life in Extreme Environments. Annu Rev Biophys 2021; 50:343-372. [PMID: 33637008 DOI: 10.1146/annurev-biophys-100120-072804] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Sampling and genomic efforts over the past decade have revealed an enormous quantity and diversity of life in Earth's extreme environments. This new knowledge of life on Earth poses the challenge of understandingits molecular basis in such inhospitable conditions, given that such conditions lead to loss of structure and of function in biomolecules from mesophiles. In this review, we discuss the physicochemical properties of extreme environments. We present the state of recent progress in extreme environmental genomics. We then present an overview of our current understanding of the biomolecular adaptation to extreme conditions. As our current and future understanding of biomolecular structure-function relationships in extremophiles requires methodologies adapted to extremes of pressure, temperature, and chemical composition, advances in instrumentation for probing biophysical properties under extreme conditions are presented. Finally, we briefly discuss possible future directions in extreme biophysics.
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Affiliation(s)
- Nozomi Ando
- Department of Chemistry & Chemical Biology, Cornell University, Ithaca, New York 14853, USA.,Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Blanca Barquera
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, USA;
| | - Douglas H Bartlett
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0202, USA
| | - Eric Boyd
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59717, USA
| | - Audrey A Burnim
- Department of Chemistry & Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Amanda S Byer
- Department of Chemistry & Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Daniel Colman
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59717, USA
| | - Richard E Gillilan
- Center for High Energy X-ray Sciences (CHEXS), Ithaca, New York 14853, USA
| | - Martin Gruebele
- Department of Chemistry, University of Illinois, Urbana-Champaign, Illinois 61801, USA.,Department of Physics, University of Illinois, Urbana-Champaign, Illinois 61801, USA.,Center for Biophysics and Quantitative Biology, University of Illinois, Urbana-Champaign, Illinois 61801, USA
| | - George Makhatadze
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, USA;
| | - Catherine A Royer
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, USA;
| | - Everett Shock
- GEOPIG, School of Earth & Space Exploration, School of Molecular Sciences, Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, Arizona 85287, USA
| | - A Joshua Wand
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77845, USA.,Department of Chemistry, Texas A&M University, College Station, Texas 77845, USA.,Department of Molecular & Cellular Medicine, Texas A&M University, College Station, Texas 77845, USA
| | - Maxwell B Watkins
- Department of Chemistry & Chemical Biology, Cornell University, Ithaca, New York 14853, USA.,Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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26
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Levengood JD, Peterson J, Tolbert BS, Roche J. Thermodynamic stability of hnRNP A1 low complexity domain revealed by high-pressure NMR. Proteins 2021; 89:781-791. [PMID: 33550645 DOI: 10.1002/prot.26058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 12/21/2020] [Accepted: 01/31/2021] [Indexed: 11/09/2022]
Abstract
We have investigated the pressure- and temperature-induced conformational changes associated with the low complexity domain of hnRNP A1, an RNA-binding protein able to phase separate in response to cellular stress. Solution NMR spectra of the hnRNP A1 low-complexity domain fused with protein-G B1 domain were collected from 1 to 2500 bar and from 268 to 290 K. While the GB1 domain shows the typical pressure-induced and cold temperature-induced unfolding expected for small globular domains, the low-complexity domain of hnRNP A1 exhibits unusual pressure and temperature dependences. We observed that the low-complexity domain is pressure sensitive, undergoing a major conformational transition within the prescribed pressure range. Remarkably, this transition has the inverse temperature dependence of a typical folding-unfolding transition. Our results suggest the presence of a low-lying extended and fully solvated state(s) of the low-complexity domain that may play a role in phase separation. This study highlights the exquisite sensitivity of solution NMR spectroscopy to observe subtle conformational changes and illustrates how pressure perturbation can be used to determine the properties of metastable conformational ensembles.
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Affiliation(s)
- Jeffrey D Levengood
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio, USA
| | - Jake Peterson
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA
| | - Blanton S Tolbert
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio, USA
| | - Julien Roche
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA
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27
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Alderson TR, Kay LE. NMR spectroscopy captures the essential role of dynamics in regulating biomolecular function. Cell 2021; 184:577-595. [PMID: 33545034 DOI: 10.1016/j.cell.2020.12.034] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/09/2020] [Accepted: 12/21/2020] [Indexed: 01/02/2023]
Abstract
Biomolecules are in constant motion. To understand how they function, and why malfunctions can cause disease, it is necessary to describe their three-dimensional structures in terms of dynamic conformational ensembles. Here, we demonstrate how nuclear magnetic resonance (NMR) spectroscopy provides an essential, dynamic view of structural biology that captures biomolecular motions at atomic resolution. We focus on examples that emphasize the diversity of biomolecules and biochemical applications that are amenable to NMR, such as elucidating functional dynamics in large molecular machines, characterizing transient conformations implicated in the onset of disease, and obtaining atomic-level descriptions of intrinsically disordered regions that make weak interactions involved in liquid-liquid phase separation. Finally, we discuss the pivotal role that NMR has played in driving forward our understanding of the biomolecular dynamics-function paradigm.
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Affiliation(s)
- T Reid Alderson
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Chemistry, The University of Toronto, Toronto, ON M5S A18, Canada.
| | - Lewis E Kay
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Chemistry, The University of Toronto, Toronto, ON M5S A18, Canada; Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada.
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28
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Xu X, Gagné D, Aramini JM, Gardner KH. Volume and compressibility differences between protein conformations revealed by high-pressure NMR. Biophys J 2021; 120:924-935. [PMID: 33524371 DOI: 10.1016/j.bpj.2020.12.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/25/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022] Open
Abstract
Proteins often interconvert between different conformations in ways critical to their function. Although manipulating such equilibria for biophysical study is often challenging, the application of pressure is a potential route to achieve such control by favoring the population of lower volume states. Here, we use this feature to study the interconversion of ARNT PAS-B Y456T, which undergoes a dramatic +3 slip in the β-strand register as it switches between two stably folded conformations. Using high-pressure biomolecular NMR approaches, we obtained the first, to our knowledge, quantitative data testing two key hypotheses of this process: the slipped conformation is both smaller and less compressible than the wild-type equivalent, and the interconversion proceeds through a chiefly unfolded intermediate state. Data collected in steady-state pressure and time-resolved pressure-jump modes, including observed pressure-dependent changes in the populations of the two conformers and increased rate of interconversion between conformers, support both hypotheses. Our work exemplifies how these approaches, which can be generally applied to protein conformational switches, can provide unique information that is not easily accessible through other techniques.
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Affiliation(s)
- Xingjian Xu
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York; Ph.D Program in Biochemistry, The Graduate Center, CUNY, New York, New York
| | - Donald Gagné
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York
| | - James M Aramini
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York
| | - Kevin H Gardner
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York; Department of Chemistry and Biochemistry, City College of New York, New York, New York; Ph.D. Programs in Biochemistry, Chemistry, and Biology, The Graduate Center, CUNY, New York, New York.
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29
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Bhatia S, Krishnamoorthy G, Udgaonkar JB. Mapping Distinct Sequences of Structure Formation Differentiating Multiple Folding Pathways of a Small Protein. J Am Chem Soc 2021; 143:1447-1457. [PMID: 33430589 DOI: 10.1021/jacs.0c11097] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
To determine experimentally how the multiple folding pathways of a protein differ, in the order in which the structural parts are assembled, has been a long-standing challenge. To resolve whether structure formation during folding can progress in multiple ways, the complex folding landscape of monellin has been characterized, structurally and temporally, using the multisite time-resolved FRET methodology. After an initial heterogeneous polypeptide chain collapse, structure formation proceeds on parallel pathways. Kinetic analysis of the population evolution data across various protein segments provides a clear structural distinction between the parallel pathways. The analysis leads to a phenomenological model that describes how and when discrete segments acquire structure independently of each other in different subensembles of protein molecules. When averaged over all molecules, structure formation is seen to progress as α-helix formation, followed by core consolidation, then β-sheet formation, and last end-to-end distance compaction. Parts of the protein that are closer in the primary sequence acquire structure before parts separated by longer sequence.
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Affiliation(s)
- Sandhya Bhatia
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560 065, India.,Indian Institute of Science Education and Research, Pune 411 008, India
| | | | - Jayant B Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560 065, India.,Indian Institute of Science Education and Research, Pune 411 008, India
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30
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Pintér G, Schwalbe H. Refolding of Cold‐Denatured Barstar Induced by Radio‐Frequency Heating: A New Method to Study Protein Folding by Real‐Time NMR Spectroscopy. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202006945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- György Pintér
- Institute for Organic Chemistry and Chemical Biology Center for Biomolecular Magnetic Resonance (BMRZ) Johann Wolfgang Goethe-Universität Frankfurt Max-von-Laue-Str. 7 60438 Frankfurt Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology Center for Biomolecular Magnetic Resonance (BMRZ) Johann Wolfgang Goethe-Universität Frankfurt Max-von-Laue-Str. 7 60438 Frankfurt Germany
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31
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Pintér G, Schwalbe H. Refolding of Cold-Denatured Barstar Induced by Radio-Frequency Heating: A New Method to Study Protein Folding by Real-Time NMR Spectroscopy. Angew Chem Int Ed Engl 2020; 59:22086-22091. [PMID: 32744407 PMCID: PMC7756886 DOI: 10.1002/anie.202006945] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/02/2020] [Indexed: 12/29/2022]
Abstract
The C40A/C82A double mutant of barstar has been shown to undergo cold denaturation above the water freezing point. By rapidly applying radio‐frequency power to lossy aqueous samples, refolding of barstar from its cold‐denatured state can be followed by real‐time NMR spectroscopy. Since temperature‐induced unfolding and refolding is reversible for this double mutant, multiple cycling can be utilized to obtain 2D real‐time NMR data. Barstar contains two proline residues that adopt a mix of cis and trans conformations in the low‐temperature‐unfolded state, which can potentially induce multiple folding pathways. The high time resolution real‐time 2D‐NMR measurements reported here show evidence for multiple folding pathways related to proline isomerization, and stable intermediates are populated. By application of advanced heating cycles and state‐correlated spectroscopy, an alternative folding pathway circumventing the rate‐limiting cis‐trans isomerization could be observed. The kinetic data revealed intermediates on both, the slow and the fast folding pathway.
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Affiliation(s)
- György Pintér
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany
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32
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Dubois C, Herrada I, Barthe P, Roumestand C. Combining High-Pressure Perturbation with NMR Spectroscopy for a Structural and Dynamical Characterization of Protein Folding Pathways. Molecules 2020; 25:E5551. [PMID: 33256081 PMCID: PMC7731413 DOI: 10.3390/molecules25235551] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/19/2020] [Accepted: 11/23/2020] [Indexed: 11/16/2022] Open
Abstract
High-hydrostatic pressure is an alternative perturbation method that can be used to destabilize globular proteins. Generally perfectly reversible, pressure exerts local effects on regions or domains of a protein containing internal voids, contrary to heat or chemical denaturant that destabilize protein structures uniformly. When combined with NMR spectroscopy, high pressure (HP) allows one to monitor at a residue-level resolution the structural transitions occurring upon unfolding and to determine the kinetic properties of the process. The use of HP-NMR has long been hampered by technical difficulties. Owing to the recent development of commercially available high-pressure sample cells, HP-NMR experiments can now be routinely performed. This review summarizes recent advances of HP-NMR techniques for the characterization at a quasi-atomic resolution of the protein folding energy landscape.
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Affiliation(s)
| | | | | | - Christian Roumestand
- Centre de Biochimie Structurale, INSERM U1054, CNRS UMR 5048, Université de Montpellier, 34090 Montpellier, France; (C.D.); (I.H.); (P.B.)
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33
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The road less traveled in protein folding: evidence for multiple pathways. Curr Opin Struct Biol 2020; 66:83-88. [PMID: 33220553 DOI: 10.1016/j.sbi.2020.10.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/11/2020] [Indexed: 11/23/2022]
Abstract
Free Energy Landscape theory of Protein Folding, introduced over 20 years ago, implies that a protein has many paths to the folded conformation with the lowest free energy. Despite the knowledge in principle, it has been remarkably hard to detect such pathways. The lack of such observations is primarily due to the fact that no one experimental technique can detect many parts of the protein simultaneously with the time resolution necessary to see such differences in paths. However, recent technical developments and employment of multiple experimental probes and folding prompts have illuminated multiple folding pathways in a number of proteins that had all previously been described with a single path.
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34
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Wakamoto T, Ikeya T, Kitazawa S, Baxter NJ, Williamson MP, Kitahara R. Paramagnetic relaxation enhancement-assisted structural characterization of a partially disordered conformation of ubiquitin. Protein Sci 2020; 28:1993-2003. [PMID: 31587403 DOI: 10.1002/pro.3734] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 11/11/2022]
Abstract
Nuclear magnetic resonance (NMR) is a powerful tool to study three-dimensional structures as well as protein conformational fluctuations in solution, but it is compromised by increases in peak widths and missing signals. We previously reported that ubiquitin has two folded conformations, N1 and N2 and plus another folded conformation, I, in which some amide group signals of residues 33-41 almost disappeared above 3 kbar at pH 4.5 and 273 K. Thus, well-converged structural models could not be obtained for this region owing to the absence of distance restraints. Here, we reexamine the problem using the ubiquitin Q41N variant as a model for this locally disordered conformation, I. We demonstrate that the variant shows pressure-induced loss of backbone amide group signals at residues 28, 33, 36, and 39-41 like the wild-type, with a similar but smaller effect on CαH and CβH signals. In order to characterize this I structure, we measured paramagnetic relaxation enhancement (PRE) under high pressure to obtain distance restraints, and calculated the structure assisted by Bayesian inference. We conclude that the more disordered I conformation observed at pH 4.0, 278 K, and 2.5 kbar largely retained the N2 conformation, although the amide groups at residues 33-41 have more heterogeneous conformations and more contact with water, which differ from the N1 and N2 states. The PRE-assisted strategy has the potential to improve structural characterization of proteins that lack NMR signals, especially for relatively more open and hydrated protein conformations.
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Affiliation(s)
- Takuro Wakamoto
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Teppei Ikeya
- Tokyo Metropolitan University, Hachioji, Tokyo, Japan
| | - Soichiro Kitazawa
- College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Nicola J Baxter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Mike P Williamson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Ryo Kitahara
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan.,College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan
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35
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Li Q, Kang C. A Practical Perspective on the Roles of Solution NMR Spectroscopy in Drug Discovery. Molecules 2020; 25:molecules25132974. [PMID: 32605297 PMCID: PMC7411973 DOI: 10.3390/molecules25132974] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 06/21/2020] [Accepted: 06/26/2020] [Indexed: 11/26/2022] Open
Abstract
Solution nuclear magnetic resonance (NMR) spectroscopy is a powerful tool to study structures and dynamics of biomolecules under physiological conditions. As there are numerous NMR-derived methods applicable to probe protein–ligand interactions, NMR has been widely utilized in drug discovery, especially in such steps as hit identification and lead optimization. NMR is frequently used to locate ligand-binding sites on a target protein and to determine ligand binding modes. NMR spectroscopy is also a unique tool in fragment-based drug design (FBDD), as it is able to investigate target-ligand interactions with diverse binding affinities. NMR spectroscopy is able to identify fragments that bind weakly to a target, making it valuable for identifying hits targeting undruggable sites. In this review, we summarize the roles of solution NMR spectroscopy in drug discovery. We describe some methods that are used in identifying fragments, understanding the mechanism of action for a ligand, and monitoring the conformational changes of a target induced by ligand binding. A number of studies have proven that 19F-NMR is very powerful in screening fragments and detecting protein conformational changes. In-cell NMR will also play important roles in drug discovery by elucidating protein-ligand interactions in living cells.
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Affiliation(s)
- Qingxin Li
- Guangdong Provincial Engineering Laboratory of Biomass High Value Utilization, Guangdong Provincial Bioengineering Institute (Guangzhou Sugarcane Industry Research Institute), Guangzhou 510316, China
- Correspondence: (Q.L.); (C.K.); Tel.: +86-020-84168436 (Q.L.); +65-64070602 (C.K.)
| | - CongBao Kang
- Experimental Drug Development Centre (EDDC), Agency for Science, Technology and Research (A*STAR), 10 Biopolis Road, Chromos, #05-01, Singapore 138670, Singapore
- Correspondence: (Q.L.); (C.K.); Tel.: +86-020-84168436 (Q.L.); +65-64070602 (C.K.)
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36
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Kim JY, Chung HS. Disordered proteins follow diverse transition paths as they fold and bind to a partner. Science 2020; 368:1253-1257. [PMID: 32527832 DOI: 10.1126/science.aba3854] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 04/10/2020] [Indexed: 01/06/2023]
Abstract
Transition paths of macromolecular conformational changes such as protein folding are predicted to be heterogeneous. However, experimental characterization of the diversity of transition paths is extremely challenging because it requires measuring more than one distance during individual transitions. In this work, we used fast three-color single-molecule Förster resonance energy transfer spectroscopy to obtain the distribution of binding transition paths of a disordered protein. About half of the transitions follow a path involving strong non-native electrostatic interactions, resulting in a transition time of 300 to 800 microseconds. The remaining half follow more diverse paths characterized by weaker electrostatic interactions and more than 10 times shorter transition path times. The chain flexibility and non-native interactions make diverse binding pathways possible, allowing disordered proteins to bind faster than folded proteins.
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Affiliation(s)
- Jae-Yeol Kim
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hoi Sung Chung
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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37
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Liu XR, Zhang MM, Gross ML. Mass Spectrometry-Based Protein Footprinting for Higher-Order Structure Analysis: Fundamentals and Applications. Chem Rev 2020; 120:4355-4454. [PMID: 32319757 PMCID: PMC7531764 DOI: 10.1021/acs.chemrev.9b00815] [Citation(s) in RCA: 130] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Proteins adopt different higher-order structures (HOS) to enable their unique biological functions. Understanding the complexities of protein higher-order structures and dynamics requires integrated approaches, where mass spectrometry (MS) is now positioned to play a key role. One of those approaches is protein footprinting. Although the initial demonstration of footprinting was for the HOS determination of protein/nucleic acid binding, the concept was later adapted to MS-based protein HOS analysis, through which different covalent labeling approaches "mark" the solvent accessible surface area (SASA) of proteins to reflect protein HOS. Hydrogen-deuterium exchange (HDX), where deuterium in D2O replaces hydrogen of the backbone amides, is the most common example of footprinting. Its advantage is that the footprint reflects SASA and hydrogen bonding, whereas one drawback is the labeling is reversible. Another example of footprinting is slow irreversible labeling of functional groups on amino acid side chains by targeted reagents with high specificity, probing structural changes at selected sites. A third footprinting approach is by reactions with fast, irreversible labeling species that are highly reactive and footprint broadly several amino acid residue side chains on the time scale of submilliseconds. All of these covalent labeling approaches combine to constitute a problem-solving toolbox that enables mass spectrometry as a valuable tool for HOS elucidation. As there has been a growing need for MS-based protein footprinting in both academia and industry owing to its high throughput capability, prompt availability, and high spatial resolution, we present a summary of the history, descriptions, principles, mechanisms, and applications of these covalent labeling approaches. Moreover, their applications are highlighted according to the biological questions they can answer. This review is intended as a tutorial for MS-based protein HOS elucidation and as a reference for investigators seeking a MS-based tool to address structural questions in protein science.
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Affiliation(s)
| | | | - Michael L. Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, USA, 63130
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38
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Wong LE, Kim TH, Rennella E, Vallurupalli P, Kay LE. Confronting the Invisible: Assignment of Protein 1H N Chemical Shifts in Cases of Extreme Broadening. J Phys Chem Lett 2020; 11:3384-3389. [PMID: 32286073 DOI: 10.1021/acs.jpclett.0c00747] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
NMR studies of intrinsically disordered proteins (IDPs) at neutral pH values are hampered by the rapid exchange of backbone amide protons with solvent. Although exchange rates can be modulated by changes in pH, interactions between IDPs that lead to phase separation sometimes only occur at neutral pH values or higher, where backbone amide-based experiments fail. Here we describe a simple NMR experiment for measuring amide proton chemical shifts in cases where 1HN spectra cannot be obtained. The approach uses a weak 1H B1 field, searching for elusive 1HN resonance frequencies that become encoded in the intensities of cross-peaks in three-dimensional 1Hα-detect spectra. Applications to the CAPRIN1 protein in both dilute- and phase-separated states highlight the utility of the method, establishing that accurate 1HN chemical shifts can be obtained even in cases where solvent hydrogen exchange rates are on the order of 1500 s-1.
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Affiliation(s)
- Leo E Wong
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Tae Hun Kim
- Program in Molecular Medicine, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada
| | - Enrico Rennella
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Pramodh Vallurupalli
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal Ranga Reddy District, Hyderabad, Telangana 500107, India
| | - Lewis E Kay
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Program in Molecular Medicine, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada
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39
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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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40
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Wiegand T, Lacabanne D, Torosyan A, Boudet J, Cadalbert R, Allain FHT, Meier BH, Böckmann A. Sedimentation Yields Long-Term Stable Protein Samples as Shown by Solid-State NMR. Front Mol Biosci 2020; 7:17. [PMID: 32154263 PMCID: PMC7047159 DOI: 10.3389/fmolb.2020.00017] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 01/30/2020] [Indexed: 01/02/2023] Open
Abstract
Today, the sedimentation of proteins into a magic-angle spinning (MAS) rotor gives access to fast and reliable sample preparation for solid-state Nuclear Magnetic Resonance (NMR), and this has allowed for the investigation of a variety of non-crystalline protein samples. High protein concentrations on the order of 400 mg/mL can be achieved, meaning that around 50–60% of the NMR rotor content is protein; the rest is a buffer solution, which includes counter ions to compensate for the charge of the protein. We have demonstrated herein the long-term stability of four sedimented proteins and complexes thereof with nucleotides, comprising a bacterial DnaB helicase, an ABC transporter, an archaeal primase, and an RNA polymerase subunit. Solid-state NMR spectra recorded directly after sample filling and up to 5 years later indicated no spectral differences and no loss in signal intensity, allowing us to conclude that protein sediments in the rotor can be stable over many years. We have illustrated, using an example of an ABC transporter, that not only the structure is maintained, but that the protein is still functional after long-term storage in the sedimented state.
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Affiliation(s)
| | | | | | - Julien Boudet
- Institute of Molecular Biology and Biophysics, ETH Zürich, Zurich, Switzerland
| | | | - Frédéric H-T Allain
- Institute of Molecular Biology and Biophysics, ETH Zürich, Zurich, Switzerland
| | - Beat H Meier
- Physical Chemistry, ETH Zürich, Zurich, Switzerland
| | - Anja Böckmann
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS/Université de Lyon, Labex Ecofect, Lyon, France
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41
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Alderson TR, Kay LE. Unveiling invisible protein states with NMR spectroscopy. Curr Opin Struct Biol 2020; 60:39-49. [DOI: 10.1016/j.sbi.2019.10.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/28/2019] [Indexed: 12/24/2022]
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Li M, Xi N, Wang Y, Liu L. Atomic Force Microscopy as a Powerful Multifunctional Tool for Probing the Behaviors of Single Proteins. IEEE Trans Nanobioscience 2020; 19:78-99. [DOI: 10.1109/tnb.2019.2954099] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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43
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Jas GS, Vallejo-Calzada R, Johnson CK, Kuczera K. Dynamic elements and kinetics: Most favorable conformations of peptides in solution with measurements and simulations. J Chem Phys 2019; 151:225102. [PMID: 31837693 DOI: 10.1063/1.5131782] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Small peptides in solution adopt a specific morphology as they function. It is of fundamental interest to examine the structural properties of these small biomolecules in solution and observe how they transition from one conformation to another and form functional structures. In this study, we have examined the structural properties of a simple dipeptide and a five-residue peptide with the application of far-UV circular dichroism (CD) spectroscopy as a function of temperature, fluorescence anisotropy, and all-atom molecular dynamics simulation. Analysis of the temperature dependent CD spectra shows that the simplest dipeptide N-acetyl-tryptophan-amide (NATA) adopts helical, beta sheet, and random coil conformations. At room temperature, NATA is found to have 5% alpha-helical, 37% beta sheet, and 58% random coil conformations. To our knowledge, this type of structural content in a simplest dipeptide has not been observed earlier. The pentapeptide (WK5) is found to have four major secondary structural elements with 8% 310 helix, 14% poly-L-proline II, 8% beta sheet, and 14% turns. A 56% unordered structural population is also present for WK5. The presence of a significant population of 310 helix in a simple pentapeptide is rarely observed. Fluorescence anisotropy decay (FAD) measurements yielded reorientation times of 45 ps for NATA and 120 ps for WK5. The fluorescence anisotropy decay measurements reveal the size differences between the two peptides, NATA and WK5, with possible contributions from differences in shape, interactions with the environment, and conformational dynamics. All-atom molecular dynamics simulations were used to model the structures and motions of these two systems in solution. The predicted structures sampled by both peptides qualitatively agree with the experimental findings. Kinetic modeling with optimal dimensionality reduction suggests that the slowest dynamic processes in the dipeptide involve sidechain transitions occurring on a 1 ns timescale. The kinetics in the pentapeptide monitors the formation of a distorted helical structure from an extended conformation on a timescale of 10 ns. Modeling of the fluorescence anisotropy decay is found to be in good agreement with the measured data and correlates with the main contributions of the measured reorientation times to individual conformers, which we define as dynamic elements. In NATA, the FAD can be well represented as a sum of contributions from representative conformers. This is not the case in WK5, where our analysis suggests the existence of coupling between conformational dynamics and global tumbling. The current study involving detailed experimental measurements and atomically detailed modeling reveals the existence of specific secondary structural elements and novel dynamical features even in the simplest peptide systems.
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Affiliation(s)
- Gouri S Jas
- Department of Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas 66047, USA
| | | | - Carey K Johnson
- Department of Chemistry, The University of Kansas, Lawrence, Kansas 66045, USA
| | - Krzysztof Kuczera
- Department of Chemistry, The University of Kansas, Lawrence, Kansas 66045, USA
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Arthanari H, Takeuchi K, Dubey A, Wagner G. Emerging solution NMR methods to illuminate the structural and dynamic properties of proteins. Curr Opin Struct Biol 2019; 58:294-304. [PMID: 31327528 PMCID: PMC6778509 DOI: 10.1016/j.sbi.2019.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 06/03/2019] [Accepted: 06/10/2019] [Indexed: 12/20/2022]
Abstract
The first recognition of protein breathing was more than 50 years ago. Today, we are able to detect the multitude of interaction modes, structural polymorphisms, and binding-induced changes in protein structure that direct function. Solution-state NMR spectroscopy has proved to be a powerful technique, not only to obtain high-resolution structures of proteins, but also to provide unique insights into the functional dynamics of proteins. Here, we summarize recent technical landmarks in solution NMR that have enabled characterization of key biological macromolecular systems. These methods have been fundamental to atomic resolution structure determination and quantitative analysis of dynamics over a wide range of time scales by NMR. The ability of NMR to detect lowly populated protein conformations and transiently formed complexes plays a critical role in its ability to elucidate functionally important structural features of proteins and their dynamics.
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Affiliation(s)
- Haribabu Arthanari
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, United States; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, United States.
| | - Koh Takeuchi
- Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, 135-0064 Tokyo, Japan.
| | - Abhinav Dubey
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, United States; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, United States
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, United States.
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Abstract
Although many proteins possess a distinct folded structure lying at a minimum in a funneled free energy landscape, thermal energy causes any protein to continuously access lowly populated excited states. The existence of excited states is an integral part of biological function. Although transitions into the excited states may lead to protein misfolding and aggregation, little structural information is currently available for them. Here, we show how NMR spectroscopy, coupled with pressure perturbation, brings these elusive species to light. As pressure acts to favor states with lower partial molar volume, NMR follows the ensuing change in the equilibrium spectroscopically, with residue-specific resolution. For T4 lysozyme L99A, relaxation dispersion NMR was used to follow the increase in population of a previously identified "invisible" folded state with pressure, as this is driven by the reduction in cavity volume by the flipping-in of a surface aromatic group. Furthermore, multiple partly disordered excited states were detected at equilibrium using pressure-dependent H/D exchange NMR spectroscopy. Here, unfolding reduced partial molar volume by the removal of empty internal cavities and packing imperfections through subglobal and global unfolding. A close correspondence was found for the distinct pressure sensitivities of various parts of the protein and the amount of internal cavity volume that was lost in each unfolding event. The free energies and populations of excited states allowed us to determine the energetic penalty of empty internal protein cavities to be 36 cal⋅Å-3.
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Bax A, Clore GM. Protein NMR: Boundless opportunities. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 306:187-191. [PMID: 31311710 PMCID: PMC6703950 DOI: 10.1016/j.jmr.2019.07.037] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 04/22/2019] [Accepted: 07/08/2019] [Indexed: 05/04/2023]
Abstract
Over the past approximately three decades, isotope-directed NMR spectroscopy has become a powerful method for determining 3D structures of biological macromolecules and their complexes in solution. From a structural perspective NMR provides an invaluable tool for studying systems that are not amenable to crystallization, including intrinsically disordered proteins and weak complexes. In contrast to both X-ray crystallography and cryo-electron microscopy which afford a largely static view of the systems under consideration, the great power of NMR lies in its ability to quantitatively probe exchange dynamics between interconverting states, and to reveal and characterize at atomic resolution the existence of transient states that may be populated at levels as low as 1%. Such "excited" states play a key role in macromolecular recognition, allostery, signal transduction and macromolecular assembly, including the initial events involved in aggregation and amyloid formation. Optimal application of NMR to such systems of fundamental biological interest requires a sound footing of the physical underpinnings of today's and tomorrow's sophisticated NMR experiments.
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Affiliation(s)
- Ad Bax
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD 20892-0520, USA.
| | - G Marius Clore
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD 20892-0520, USA.
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47
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Barnes CA, Robertson AJ, Louis JM, Anfinrud P, Bax A. Observation of β-Amyloid Peptide Oligomerization by Pressure-Jump NMR Spectroscopy. J Am Chem Soc 2019; 141:13762-13766. [DOI: 10.1021/jacs.9b06970] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- C. Ashley Barnes
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Angus J. Robertson
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - John M. Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Philip Anfinrud
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
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Thirumalai D, Samanta HS, Maity H, Reddy G. Universal Nature of Collapsibility in the Context of Protein Folding and Evolution. Trends Biochem Sci 2019; 44:675-687. [DOI: 10.1016/j.tibs.2019.04.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 04/03/2019] [Accepted: 04/04/2019] [Indexed: 12/21/2022]
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Kerr JD, Balcom BJ, McCarthy MJ, Augustine MP. A low cost, portable NMR probe for high pressure, MR relaxometry. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 304:35-41. [PMID: 31077930 DOI: 10.1016/j.jmr.2019.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/02/2019] [Accepted: 05/02/2019] [Indexed: 06/09/2023]
Abstract
A low cost, portable, high volume, stainless steel pressure reactor is modified to easily perform magnetic resonance relaxometry at industrially relevant pressures. Unlike existing pressurization strategies common to nuclear magnetic resonance (NMR) spectroscopy, this approach is amenable to realistic samples that feature heterogeneity and have traditionally escaped NMR study at pressure. This pressure reactor/NMR probe combination is easily accommodated by most single-sided and other low magnetic field permanent magnet assemblies. The performance of the probe is demonstrated by accomplishing NMR relaxometry on polydimethylsiloxane at different pressures with two types of unilateral magnets.
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Affiliation(s)
- Julia D Kerr
- Department of Chemistry, 69 Chemistry Building, University of California, Davis, Davis, CA 95616 USA
| | - Bruce J Balcom
- Department of Physics, UNB MRI Centre, University of New Brunswick, Fredericton, New Brunswick, Canada
| | - Michael J McCarthy
- Department of Chemistry, 69 Chemistry Building, University of California, Davis, Davis, CA 95616 USA
| | - Matthew P Augustine
- Department of Chemistry, 69 Chemistry Building, University of California, Davis, Davis, CA 95616 USA.
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50
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Stiller JB, Kerns SJ, Hoemberger M, Cho YJ, Otten R, Hagan MF, Kern D. Probing the Transition State in Enzyme Catalysis by High-Pressure NMR Dynamics. Nat Catal 2019; 2:726-734. [PMID: 32159076 DOI: 10.1038/s41929-019-0307-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protein conformational changes are frequently essential for enzyme catalysis, and in several cases, shown to be the limiting factor for overall catalytic speed. However, a structural understanding of corresponding transition states, needed to rationalize the kinetics, remains obscure due to their fleeting nature. Here, we determine the transition-state ensemble of the rate-limiting conformational transition in the enzyme adenylate kinase, by a synergistic approach between experimental high-pressure NMR relaxation during catalysis and molecular dynamics simulations. By comparing homologous kinases evolved under ambient or high pressure in the deep-sea, we detail transition state ensembles that differ in solvation as directly measured by the pressure dependence of catalysis. Capturing transition-state ensembles begins to complete the catalytic energy landscape that is generally characterized by structures of all intermediates and frequencies of transitions among them.
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Affiliation(s)
- John B Stiller
- Department of Biochemistry and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02452, United States
| | - S Jordan Kerns
- Department of Biochemistry and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02452, United States.,Present addresses: S.J.K. 27 Drydock Ave, Boston MA 02110 , M.H. 225 Binney St, Cambridge, MA 02142, Y.J.C. 733 Concord Ave Cambridge, MA 02138
| | - Marc Hoemberger
- Department of Biochemistry and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02452, United States.,Present addresses: S.J.K. 27 Drydock Ave, Boston MA 02110 , M.H. 225 Binney St, Cambridge, MA 02142, Y.J.C. 733 Concord Ave Cambridge, MA 02138
| | - Young-Jin Cho
- Department of Biochemistry and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02452, United States.,Present addresses: S.J.K. 27 Drydock Ave, Boston MA 02110 , M.H. 225 Binney St, Cambridge, MA 02142, Y.J.C. 733 Concord Ave Cambridge, MA 02138
| | - Renee Otten
- Department of Biochemistry and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02452, United States
| | - Michael F Hagan
- Department of Physics, Brandeis University, Waltham, Massachusetts 02452, United States
| | - Dorothee Kern
- Department of Biochemistry and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02452, United States
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