1
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Seelig J, Seelig A. Protein Stability─Analysis of Heat and Cold Denaturation without and with Unfolding Models. J Phys Chem B 2023; 127:3352-3363. [PMID: 37040567 PMCID: PMC10123674 DOI: 10.1021/acs.jpcb.3c00882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
Protein stability is important in many areas of life sciences. Thermal protein unfolding is investigated extensively with various spectroscopic techniques. The extraction of thermodynamic properties from these measurements requires the application of models. Differential scanning calorimetry (DSC) is less common, but is unique as it measures directly a thermodynamic property, that is, the heat capacity Cp(T). The analysis of Cp(T) is usually performed with the chemical equilibrium two-state model. This is not necessary and leads to incorrect thermodynamic consequences. Here we demonstrate a straightforward model-independent evaluation of heat capacity experiments in terms of protein unfolding enthalpy ΔH(T), entropy ΔS(T), and free energy ΔG(T)). This now allows the comparison of the experimental thermodynamic data with the predictions of different models. We critically examined the standard chemical equilibrium two-state model, which predicts a positive free energy for the native protein, and diverges distinctly from the experimental temperature profiles. We propose two new models which are equally applicable to spectroscopy and calorimetry. The ΘU(T)-weighted chemical equilibrium model and the statistical-mechanical two-state model provide excellent fits of the experimental data. They predict sigmoidal temperature profiles for enthalpy and entropy, and a trapezoidal temperature profile for the free energy. This is illustrated with experimental examples for heat and cold denaturation of lysozyme and β-lactoglobulin. We then show that the free energy is not a good criterion to judge protein stability. More useful parameters are discussed, including protein cooperativity. The new parameters are embedded in a well-defined thermodynamic context and are amenable to molecular dynamics calculations.
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Affiliation(s)
- Joachim Seelig
- Biozentrum, University of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland
| | - Anna Seelig
- Biozentrum, University of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland
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2
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Mohanakumar S, Lee N, Wiegand S. Complementary Experimental Methods to Obtain Thermodynamic Parameters of Protein Ligand Systems. Int J Mol Sci 2022; 23:ijms232214198. [PMID: 36430678 PMCID: PMC9692857 DOI: 10.3390/ijms232214198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/10/2022] [Accepted: 11/12/2022] [Indexed: 11/18/2022] Open
Abstract
In recent years, thermophoresis has emerged as a promising tool for quantifying biomolecular interactions. The underlying microscopic physical effect is still not understood, but often attributed to changes in the hydration layer once the binding occurs. To gain deeper insight, we investigate whether non-equilibrium coefficients can be related to equilibrium properties. Therefore, we compare thermophoretic data measured by thermal diffusion forced Rayleigh scattering (TDFRS) (which is a non-equilibrium process) with thermodynamic data obtained by isothermal titration calorimetry (ITC) (which is an equilibrium process). As a reference system, we studied the chelation reaction between ethylenediaminetetraacetic acid (EDTA) and calcium chloride (CaCl2) to relate the thermophoretic behavior quantified by the Soret coefficient ST to the Gibb's free energy ΔG determined in the ITC experiment using an expression proposed by Eastman. Finally, we have studied the binding of the protein Bovine Carbonic Anhydrase I (BCA I) to two different benzenesulfonamide derivatives: 4-fluorobenzenesulfonamide (4FBS) and pentafluorobenzenesulfonamide (PFBS). For all three systems, we find that the Gibb's free energies calculated from ST agree with ΔG from the ITC experiment. In addition, we also investigate the influence of fluorescent labeling, which allows measurements in a thermophoretic microfluidic cell. Re-examination of the fluorescently labeled system using ITC showed a strong influence of the dye on the binding behavior.
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Affiliation(s)
- Shilpa Mohanakumar
- IBI-4—Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Namkyu Lee
- IBI-4—Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Simone Wiegand
- IBI-4—Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
- Chemistry Department-Physical Chemistry, University of Colgone, D-50939 Cologne, Germany
- Correspondence: ; Tel.: +49-2461-61-6654
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3
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Tang C, Wang Y, Cheng J, Chang C, Hu J, Lü J. Probing terahertz dynamics of multidomain protein in cell-like confinement. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 275:121173. [PMID: 35334430 DOI: 10.1016/j.saa.2022.121173] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 03/13/2022] [Accepted: 03/15/2022] [Indexed: 06/14/2023]
Abstract
The development of meaningful descriptions of multidomain proteins exhibiting complex inter-domain dynamics modes is a key challenge for understanding their roles in molecular recognition and signalling processes. Here we developed a generally applicable approach for probing the low frequency collective hydration dynamics of multidomain proteins that uses terahertz spectroscopy of a protein molecule confined in a phospholipid reverse micelles environment (named Droplet THz). With the combination of normal mode analysis, we demonstrated the binding of calcium ions modulates the local inter-domain motion of the human coagulant factor VIII protein in a concentration-dependent manner. These findings highlight the Droplet THz as a valuable tool for dissecting the ultrafast dynamics of domain motion in the multidomain proteins and suggest a modulating mechanism of calcium ions on the structural flexibility and function of human coagulant proteins.
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Affiliation(s)
- Chao Tang
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201203, China; Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Yadi Wang
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201203, China; Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China; College of Pharmacy, Binzhou Medical University, Yantai 264003, China
| | - Jie Cheng
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201203, China; Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Chao Chang
- Advanced Interdisciplinary Technology Research Center, National Innovation Institute of Defense Technology, Beijing 100071, China.
| | - Jun Hu
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201203, China; Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Junhong Lü
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201203, China; Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China; College of Pharmacy, Binzhou Medical University, Yantai 264003, China.
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4
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Haris L, Biehl R, Dulle M, Radulescu A, Holderer O, Hoffmann I, Stadler AM. Variation of Structural and Dynamical Flexibility of Myelin Basic Protein in Response to Guanidinium Chloride. Int J Mol Sci 2022; 23:ijms23136969. [PMID: 35805997 PMCID: PMC9266411 DOI: 10.3390/ijms23136969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/18/2022] [Accepted: 06/21/2022] [Indexed: 11/16/2022] Open
Abstract
Myelin basic protein (MBP) is intrinsically disordered in solution and is considered as a conformationally flexible biomacromolecule. Here, we present a study on perturbation of MBP structure and dynamics by the denaturant guanidinium chloride (GndCl) using small-angle scattering and neutron spin–echo spectroscopy (NSE). A concentration of 0.2 M GndCl causes charge screening in MBP resulting in a compact, but still disordered protein conformation, while GndCl concentrations above 1 M lead to structural expansion and swelling of MBP. NSE data of MBP were analyzed using the Zimm model with internal friction (ZIF) and normal mode (NM) analysis. A significant contribution of internal friction was found in compact states of MBP that approaches a non-vanishing internal friction relaxation time of approximately 40 ns at high GndCl concentrations. NM analysis demonstrates that the relaxation rates of internal modes of MBP remain unaffected by GndCl, while structural expansion due to GndCl results in increased amplitudes of internal motions. Within the model of the Brownian oscillator our observations can be rationalized by a loss of friction within the protein due to structural expansion. Our study highlights the intimate coupling of structural and dynamical plasticity of MBP, and its fundamental difference to the behavior of ideal polymers in solution.
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Affiliation(s)
- Luman Haris
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; (L.H.); (R.B.); (M.D.)
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
| | - Ralf Biehl
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; (L.H.); (R.B.); (M.D.)
| | - Martin Dulle
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; (L.H.); (R.B.); (M.D.)
| | - Aurel Radulescu
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungzentrum Jülich GmbH, 85747 Garching, Germany; (A.R.); (O.H.)
| | - Olaf Holderer
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungzentrum Jülich GmbH, 85747 Garching, Germany; (A.R.); (O.H.)
| | - Ingo Hoffmann
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, CEDEX 9, 38042 Grenoble, France;
| | - Andreas M. Stadler
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; (L.H.); (R.B.); (M.D.)
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
- Correspondence:
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5
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Seelig J, Seelig A. Molecular understanding of calorimetric protein unfolding experiments. BIOPHYSICAL REPORTS 2022; 2:100037. [PMID: 36425081 PMCID: PMC9680786 DOI: 10.1016/j.bpr.2021.100037] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 12/02/2021] [Indexed: 06/16/2023]
Abstract
Testing and predicting protein stability gained importance because proteins, including antibodies, became pharmacologically relevant in viral and cancer therapies. Isothermal scanning calorimetry is the principle method to study protein stability. Here, we use the excellent experimental heat capacity Cp(T) data from the literature for a critical inspection of protein unfolding as well as for the test of a new cooperative model. In the relevant literature, experimental temperature profiles of enthalpy, Hcal(T), entropy, Scal(T), and free energy, Gcal(T) are missing. First, we therefore calculate the experimental Hcal(T), Scal(T), and Gcal(T) from published Cp(T) thermograms. Considering only the unfolding transition proper, the heat capacity and all thermodynamic functions are zero in the region of the native protein. In particular, the free energy of the folded proteins is also zero and Gcal(T) displays a trapezoidal temperature profile when cold denaturation is included. Second, we simulate the DSC-measured thermodynamic properties with a new molecular model based on statistical-mechanical thermodynamics. The model quantifies the protein cooperativity and predicts the aggregate thermodynamic variables of the system with molecular parameters only. The new model provides a perfect simulation of all thermodynamic properties, including the observed trapezoidal Gcal(T) temperature profile. Importantly, the new cooperative model can be applied to a broad range of protein sizes, including antibodies. It predicts not only heat and cold denaturation but also provides estimates of the unfolding kinetics and allows a comparison with molecular dynamics calculations and quasielastic neutron scattering experiments.
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Affiliation(s)
| | - Anna Seelig
- Biozentrum, University of Basel, Basel, Switzerland
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6
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Fagerberg E, Lenton S, Nylander T, Seydel T, Skepö M. Self-Diffusive Properties of the Intrinsically Disordered Protein Histatin 5 and the Impact of Crowding Thereon: A Combined Neutron Spectroscopy and Molecular Dynamics Simulation Study. J Phys Chem B 2022; 126:789-801. [PMID: 35044776 PMCID: PMC8819652 DOI: 10.1021/acs.jpcb.1c08976] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
![]()
Intrinsically disordered
proteins (IDPs) are proteins that, in
comparison with globular/structured proteins, lack a distinct tertiary
structure. Here, we use the model IDP, Histatin 5, for studying its
dynamical properties under self-crowding conditions with quasi-elastic
neutron scattering in combination with full atomistic molecular dynamics
(MD) simulations. The aim is to determine the effects of crowding
on the center-of-mass diffusion as well as the internal diffusive
behavior. The diffusion was found to decrease significantly, which
we hypothesize can be attributed to some degree of aggregation at
higher protein concentrations, (≥100 mg/mL), as indicated by
recent small-angle X-ray scattering studies. Temperature effects are
also considered and found to, largely, follow Stokes–Einstein
behavior. Simple geometric considerations fail to accurately predict
the rates of diffusion, while simulations show semiquantitative agreement
with experiments, dependent on assumptions of the ratio between translational
and rotational diffusion. A scaling law that previously was found
to successfully describe the behavior of globular proteins was found
to be inadequate for the IDP, Histatin 5. Analysis of the MD simulations
show that the width of the distribution with respect to diffusion
is not a simplistic mirroring of the distribution of radius of gyration,
hence, displaying the particular features of IDPs that need to be
accounted for.
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Affiliation(s)
- Eric Fagerberg
- Theoretical Chemistry, Lund University, POB 124, SE-221 00 Lund, Sweden
| | - Samuel Lenton
- Physical Chemistry, Lund University, POB 124, SE-221 00 Lund, Sweden
| | - Tommy Nylander
- Physical Chemistry, Lund University, POB 124, SE-221 00 Lund, Sweden
| | - Tilo Seydel
- Institut Max von Laue - Paul Langevin, 71 avenue des Martyrs, CS 20156, F-38042 Grenoble, France
| | - Marie Skepö
- Theoretical Chemistry, Lund University, POB 124, SE-221 00 Lund, Sweden.,LINXS - Lund Institute of Advanced Neutron and X-ray Science, Scheelevägen 19, SE-223 70 Lund, Sweden
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7
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Matsuo T, De Francesco A, Peters J. Molecular Dynamics of Lysozyme Amyloid Polymorphs Studied by Incoherent Neutron Scattering. Front Mol Biosci 2022; 8:812096. [PMID: 35111814 PMCID: PMC8801425 DOI: 10.3389/fmolb.2021.812096] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 12/03/2021] [Indexed: 11/22/2022] Open
Abstract
Lysozyme amyloidosis is a hereditary disease, which is characterized by the deposition of lysozyme amyloid fibrils in various internal organs. It is known that lysozyme fibrils show polymorphism and that polymorphs formed at near-neutral pH have the ability to promote more monomer binding than those formed at acidic pH, indicating that only specific polymorphs become dominant species in a given environment. This is likely due to the polymorph-specific configurational diffusion. Understanding the possible differences in dynamical behavior between the polymorphs is thus crucial to deepen our knowledge of amyloid polymorphism and eventually elucidate the molecular mechanism of lysozyme amyloidosis. In this study, molecular dynamics at sub-nanosecond timescale of two kinds of polymorphic fibrils of hen egg white lysozyme, which has long been used as a model of human lysozyme, formed at pH 2.7 (LP27) and pH 6.0 (LP60) was investigated using elastic incoherent neutron scattering (EINS) and quasi-elastic neutron scattering (QENS). Analysis of the EINS data showed that whereas the mean square displacement of atomic motions is similar for both LP27 and LP60, LP60 contains a larger fraction of atoms moving with larger amplitudes than LP27, indicating that the dynamical difference between the two polymorphs lies not in the averaged amplitude, but in the distribution of the amplitudes. Furthermore, analysis of the QENS data showed that the jump diffusion coefficient of atoms is larger for LP60, suggesting that the atoms of LP60 undergo faster diffusive motions than those of LP27. This study thus characterizes the dynamics of the two lysozyme polymorphs and reveals that the molecular dynamics of LP60 is enhanced compared with that of LP27. The higher molecular flexibility of the polymorph would permit to adjust its conformation more quickly than its counterpart, facilitating monomer binding.
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Affiliation(s)
- Tatsuhito Matsuo
- Univ. Grenoble Alpes, CNRS, LiPhy, Grenoble, France
- Institut Laue-Langevin, Grenoble, France
- Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Tokai, Japan
- *Correspondence: Tatsuhito Matsuo, ; Judith Peters,
| | - Alessio De Francesco
- Institut Laue-Langevin, Grenoble, France
- CNR-IOM and INSIDE@ILL C/O Operative Group in Grenoble (OGG), Grenoble, France
| | - Judith Peters
- Univ. Grenoble Alpes, CNRS, LiPhy, Grenoble, France
- Institut Laue-Langevin, Grenoble, France
- Institut Universitaire de France, Paris, France
- *Correspondence: Tatsuhito Matsuo, ; Judith Peters,
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8
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Sarter M, Niether D, Wiegand S, Fitter J, Stadler AM. Complementary approaches to obtaining thermodynamic parameters from protein ligand systems-challenges and opportunities. EPJ WEB OF CONFERENCES 2022. [DOI: 10.1051/epjconf/202227201016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein ligand interactions play an important role in biology. Increasingly the aim is to understand and influence protein ligand binding. The binding process is heavily influenced by its thermodynamic parameters. In order to understand how the whole system thermodynamics work it is important to characterise the individual contribution of each of the systems components. While the change in conformational entropy of the protein can be determined using QENS complementary methods are necessary in order to characterise all components. This paper will describe the challenges that can occur when combining the different methods, as well as how they can be overcome.
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9
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Light Scattering and Absorption Complementarities to Neutron Scattering: In Situ FTIR and DLS Techniques at the High-Intensity and Extended Q-Range SANS Diffractometer KWS-2. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11115135] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Understanding soft and biological materials requires global knowledge of their microstructural features from elementary units at the nm scale up to larger complex aggregates in the micrometer range. Such a wide range of scale can be explored using the KWS-2 small-angle neutron (SANS) diffractometer. Additional information obtained by in situ complementary techniques sometimes supports the SANS analysis of systems undergoing structural modifications under external stimuli or which are stable only for short times. Observations at the local molecular level structure and conformation assists with an unambiguous interpretation of the SANS data using appropriate structural models, while monitoring of the sample condition during the SANS investigation ensures the sample stability and desired composition and chemical conditions. Thus, we equipped the KWS-2 with complementary light absorption and scattering capabilities: Fourier transform infrared (FTIR) spectroscopy can now be performed simultaneously with standard and time-resolved SANS, while in situ dynamic light scattering (DLS) became available for routine experiments, which enables the observation of either changes in the sample composition, due to sedimentation effects, or in size of morphologies, due to aggregation processes. The performance of each setup is demonstrated here using systems representative of those typically investigated on this beamline and benchmarked to studies performed offline.
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10
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Konermann L, Aliyari E, Lee JH. Mobile Protons Limit the Stability of Salt Bridges in the Gas Phase: Implications for the Structures of Electrosprayed Protein Ions. J Phys Chem B 2021; 125:3803-3814. [PMID: 33848419 DOI: 10.1021/acs.jpcb.1c00944] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Electrosprayed protein ions can retain native-like conformations. The intramolecular contacts that stabilize these compact gas-phase structures remain poorly understood. Recent work has uncovered abundant salt bridges in electrosprayed proteins. Salt bridges are zwitterionic BH+/A- contacts. The low dielectric constant in the vacuum strengthens electrostatic interactions, suggesting that salt bridges could be a key contributor to the retention of compact protein structures. A problem with this assertion is that H+ are mobile, such that H+ transfer can convert salt bridges into neutral B0/HA0 contacts. This possible salt bridge annihilation puts into question the role of zwitterionic motifs in the gas phase, and it calls for a detailed analysis of BH+/A- versus B0/HA0 interactions. Here, we investigate this issue using molecular dynamics (MD) simulations and electrospray experiments. MD data for short model peptides revealed that salt bridges with static H+ have dissociation energies around 700 kJ mol-1. The corresponding B0/HA0 contacts are 1 order of magnitude weaker. When considering the effects of mobile H+, BH+/A- bond energies were found to be between these two extremes, confirming that H+ migration can significantly weaken salt bridges. Next, we examined the protein ubiquitin under collision-induced unfolding (CIU) conditions. CIU simulations were conducted using three different MD models: (i) Positive-only runs with static H+ did not allow for salt bridge formation and produced highly expanded CIU structures. (ii) Zwitterionic runs with static H+ resulted in abundant salt bridges, culminating in much more compact CIU structures. (iii) Mobile H+ simulations allowed for the dynamic formation/annihilation of salt bridges, generating CIU structures intermediate between scenarios (i) and (ii). Our results uncover that mobile H+ limit the stabilizing effects of salt bridges in the gas phase. Failure to consider the effects of mobile H+ in MD simulations will result in unrealistic outcomes under CIU conditions.
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Affiliation(s)
- Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Elnaz Aliyari
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Justin H Lee
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
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11
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Shou K, Sarter M, de Souza NR, de Campo L, Whitten AE, Kuchel PW, Garvey CJ, Stadler AM. Effect of red blood cell shape changes on haemoglobin interactions and dynamics: a neutron scattering study. ROYAL SOCIETY OPEN SCIENCE 2020; 7:201507. [PMID: 33204483 PMCID: PMC7657910 DOI: 10.1098/rsos.201507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 09/18/2020] [Indexed: 06/11/2023]
Abstract
By using a combination of experimental neutron scattering techniques, it is possible to obtain a statistical perspective on red blood cell (RBC) shape in suspensions, and the inter-relationship with protein interactions and dynamics inside the confinement of the cell membrane. In this study, we examined the ultrastructure of RBC and protein-protein interactions of haemoglobin (Hb) in them using ultra-small-angle neutron scattering and small-angle neutron scattering (SANS). In addition, we used the neutron backscattering method to access Hb motion on the ns time scale and Å length scale. Quasi-elastic neutron scattering (QENS) experiments were performed to measure diffusive motion of Hb in RBCs and in an RBC lysate. By using QENS, we probed both internal Hb dynamics and global protein diffusion, on the accessible time scale and length scale by QENS. Shape changes of RBCs and variation of intracellular Hb concentration were induced by addition of the Na+-selective ionophore monensin and the K+-selective one, valinomycin. The experimental SANS and QENS results are discussed within the framework of crowded protein solutions, where free motion of Hb is obstructed by mutual interactions.
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Affiliation(s)
- Keyun Shou
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8: Neutron Scattering and Biological Matter), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
- Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234, Australia
| | - Mona Sarter
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8: Neutron Scattering and Biological Matter), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
- I. Physikalisches Institut (IA), AG Biophysik, RWTH Aachen, Sommerfeldstrasse 14, 52074 Aachen, Germany
| | - Nicolas R. de Souza
- Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234, Australia
| | - Liliana de Campo
- Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234, Australia
| | - Andrew E. Whitten
- Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234, Australia
| | - Philip W. Kuchel
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Christopher J. Garvey
- Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234, Australia
- Biofilm—Research Center for Biointerfaces and Biomedical Science Department, Faculty of Health and Society, Malmö University, Malmö, Sweden
- Lund Institute for Advanced Neutron and X-ray Science, Lund, Sweden
| | - Andreas M. Stadler
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8: Neutron Scattering and Biological Matter), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
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12
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Thermophoresis: The Case of Streptavidin and Biotin. Polymers (Basel) 2020; 12:polym12020376. [PMID: 32046223 PMCID: PMC7077373 DOI: 10.3390/polym12020376] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/27/2020] [Accepted: 01/29/2020] [Indexed: 02/02/2023] Open
Abstract
Thermophoretic behavior of a free protein changes upon ligand binding and gives access to information on the binding constants. The Soret effect has also been proven to be a promising tool to gain information on the hydration layer, as the temperature dependence of the thermodiffusion behavior is sensitive to solute–solvent interactions. In this work, we perform systematic thermophoretic measurements of the protein streptavidin (STV) and of the complex STV with biotin (B) using thermal diffusion forced Rayleigh scattering (TDFRS). Our experiments show that the temperature sensitivity of the Soret coefficient is reduced for the complex compared to the free protein. We discuss our data in comparison with recent quasi-elastic neutron scattering (QENS) measurements. As the QENS measurement has been performed in heavy water, we perform additional measurements in water/heavy water mixtures. Finally, we also elucidate the challenges arising from the quantiative thermophoretic study of complex multicomponent systems such as protein solutions.
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13
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Transition between protein-like and polymer-like dynamic behavior: Internal friction in unfolded apomyoglobin depends on denaturing conditions. Sci Rep 2020; 10:1570. [PMID: 32005832 PMCID: PMC6994677 DOI: 10.1038/s41598-020-57775-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 01/06/2020] [Indexed: 11/22/2022] Open
Abstract
Equilibrium dynamics of different folding intermediates and denatured states is strongly connected to the exploration of the conformational space on the nanosecond time scale and might have implications in understanding protein folding. For the first time, the same protein system apomyoglobin has been investigated using neutron spin-echo spectroscopy in different states: native-like, partially folded (molten globule) and completely unfolded, following two different unfolding paths: using acid or guanidinium chloride (GdmCl). While the internal dynamics of the native-like state can be understood using normal mode analysis based on high resolution structural information of myoglobin, for the unfolded and even for the molten globule states, models from polymer science are employed. The Zimm model accurately describes the slowly-relaxing, expanded GdmCl-denaturated state, ignoring the individuality of the different aminoacid side chain. The dynamics of the acid unfolded and molten globule state are similar in the framework of the Zimm model with internal friction, where the chains still interact and hinder each other: the first Zimm relaxation time is as large as the internal friction time. Transient formation of secondary structure elements in the acid unfolded and presence of α-helices in the molten globule state lead to internal friction to a similar extent.
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Sarter M, Niether D, Koenig BW, Lohstroh W, Zamponi M, Jalarvo NH, Wiegand S, Fitter J, Stadler AM. Strong Adverse Contribution of Conformational Dynamics to Streptavidin-Biotin Binding. J Phys Chem B 2019; 124:324-335. [PMID: 31710813 DOI: 10.1021/acs.jpcb.9b08467] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Molecular dynamics plays an important role for the biological function of proteins. For protein ligand interactions, changes of conformational entropy of protein and hydration layer are relevant for the binding process. Quasielastic neutron scattering (QENS) was used to investigate differences in protein dynamics and conformational entropy of ligand-bound and ligand-free streptavidin. Protein dynamics were probed both on the fast picosecond time scale using neutron time-of-flight spectroscopy and on the slower nanosecond time scale using high-resolution neutron backscattering spectroscopy. We found the internal equilibrium motions of streptavidin and the corresponding mean square displacements (MSDs) to be greatly reduced upon biotin binding. On the basis of the observed MSDs, we calculated the difference of conformational entropy ΔSconf of the protein component between ligand-bound and ligand-free streptavidin. The rather large negative ΔSconf value (-2 kJ mol-1 K-1 on the nanosecond time scale) obtained for the streptavidin tetramer seems to be counterintuitive, given the exceptionally high affinity of streptavidin-biotin binding. Literature data on the total entropy change ΔS observed upon biotin binding to streptavidin, which includes contributions from both the protein and the hydration water, suggest partial compensation of the unfavorable ΔSconf by a large positive entropy gain of the surrounding hydration layer and water molecules that are displaced during ligand binding.
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Affiliation(s)
- Mona Sarter
- I. Physikalisches Institut (IA), AG Biophysik , RWTH Aachen , Sommerfeldstrasse 14 , Aachen D-52074 , Germany
| | | | | | - Wiebke Lohstroh
- Heinz Maier-Leibnitz Zentrum , Technische Universität München , Garching D-85747 , Germany
| | - Michaela Zamponi
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ) , Forschungszentrum Jülich GmbH , Lichtenbergstrasse 1 , Garching D-85748 , Germany
| | - Niina H Jalarvo
- Neutron Scattering Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831-6475 , United States
| | - Simone Wiegand
- Department für Chemie - Physikalische Chemie , Universität zu Köln , Cologne D-50939 , Germany
| | - Jörg Fitter
- I. Physikalisches Institut (IA), AG Biophysik , RWTH Aachen , Sommerfeldstrasse 14 , Aachen D-52074 , Germany.,Institute of Complex Systems, Molecular Biophysics (ICS-5) , Forschungszentrum Jülich GmbH , Jülich D-52428 , Germany
| | - Andreas M Stadler
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , Aachen D-52056 , Germany
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Salvador-Castell M, Golub M, Martinez N, Ollivier J, Peters J, Oger P. The first study on the impact of osmolytes in whole cells of high temperature-adapted microorganisms. SOFT MATTER 2019; 15:8381-8391. [PMID: 31613294 DOI: 10.1039/c9sm01196j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The hyperthermophilic piezophile, Thermococcus barophilus displays a strong stress response characterized by the accumulation of the organic osmolyte, mannosylglycerate during growth under sub-optimal pressure conditions (0.1 MPa). Taking advantage of this known effect, the impact of osmolytes in piezophiles in an otherwise identical cellular context was investigated, by comparing T. barophilus cells grown under low or optimal pressures (40 MPa). Using neutron scattering techniques, we studied the molecular dynamics of live cells of T. barophilus at different pressures and temperatures. We show that in the presence of osmolytes, cells present a higher diffusion coefficient of hydration water and an increase of bulk water motions at a high temperature. In the absence of osmolytes, the T. barophilus cellular dynamics is more responsive to high temperature and high hydrostatic pressure. These results therefore give clear evidence for a protecting effect of osmolytes on proteins.
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Shou K, Bremer A, Rindfleisch T, Knox-Brown P, Hirai M, Rekas A, Garvey CJ, Hincha DK, Stadler AM, Thalhammer A. Conformational selection of the intrinsically disordered plant stress protein COR15A in response to solution osmolarity - an X-ray and light scattering study. Phys Chem Chem Phys 2019; 21:18727-18740. [PMID: 31424463 DOI: 10.1039/c9cp01768b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The plant stress protein COR15A stabilizes chloroplast membranes during freezing. COR15A is an intrinsically disordered protein (IDP) in aqueous solution, but acquires an α-helical structure during dehydration or the increase of solution osmolarity. We have used small- and wide-angle X-ray scattering (SAXS/WAXS) combined with static and dynamic light scattering (SLS/DLS) to investigate the structural and hydrodynamic properties of COR15A in response to increasing solution osmolarity. Coarse-grained ensemble modelling allowed a structure-based interpretation of the SAXS data. Our results demonstrate that COR15A behaves as a biomacromolecule with polymer-like properties which strongly depend on solution osmolarity. Biomacromolecular self-assembly occurring at high solvent osmolarity is initiated by the occurrence of two specific structural subpopulations of the COR15A monomer. The osmolarity dependent structural selection mechanism is an elegant way for conformational regulation and assembly of COR15A. It highlights the importance of the polymer-like properties of IDPs for their associated biological function.
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Affiliation(s)
- Keyun Shou
- Jülich Centre for Neutron Science (JCNS-1) and Institute for Complex Systems (ICS-1), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
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17
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Hirai M, Ajito S, Iwase H, Takata SI, Ohta N, Igarashi N, Shimizu N. Restoration of Myoglobin Native Fold from Its Initial State of Amyloid Formation by Trehalose. J Phys Chem B 2018; 122:11962-11968. [DOI: 10.1021/acs.jpcb.8b09379] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Mitsuhiro Hirai
- Graduate School of Science and Technology, Gunma University, 4-2 Aramaki, Maebashi, Gunma 371-8510, Japan
| | - Satoshi Ajito
- Graduate School of Science and Technology, Gunma University, 4-2 Aramaki, Maebashi, Gunma 371-8510, Japan
| | - Hiroki Iwase
- Comprehensive Research Organization for Science and Society, Tokai 319-1106, Japan
| | - Shin-ichi Takata
- J-PARC Center, Japan Atomic Energy Agency, Tokai 319-1106, Japan
| | - Noboru Ohta
- Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Noriyuki Igarashi
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Nobutaka Shimizu
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
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Niether D, Kawaguchi T, Hovancová J, Eguchi K, Dhont JKG, Kita R, Wiegand S. Role of Hydrogen Bonding of Cyclodextrin-Drug Complexes Probed by Thermodiffusion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:8483-8492. [PMID: 28780866 DOI: 10.1021/acs.langmuir.7b02313] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Temperature gradient-induced migration of biomolecules, known as thermophoresis or thermodiffusion, changes upon ligand binding. In recent years, this effect has been used to determine protein-ligand binding constants. The mechanism through which thermodiffusive properties change when complexes are formed, however, is not understood. An important contribution to thermodiffusive properties originates from the thermal response of hydrogen bonds. Because there is a considerable difference between the degree of solvation of the protein-ligand complex and its isolated components, ligand-binding is accompanied by a significant change in hydration. The aim of the present work is therefore to investigate the role played by hydrogen bonding on the change in thermodiffusive behavior upon ligand-binding. As a model system, we use cyclodextrins (CDs) and acetylsalicylic acid (ASA), where quite a significant change in hydration is expected and where no conformational changes occur when a CD/ASA complex is formed in aqueous solution. Thermophoresis was investigated in the temperature range of 10-50 °C by infrared thermal diffusion forced Rayleigh scattering. Nuclear magnetic resonance measurements were performed at 25 °C to obtain information about the structure of the complexes. All CD/ASA complexes show a stronger affinity toward regions of lower temperature compared to the free CDs. We found that the temperature sensitivity of thermophoresis correlates with the 1-octanol/water partition coefficient. This observation not only establishes the relation between thermodiffusion and degree of hydrogen bonding but also opens the possibility to relate thermodiffusive properties of complexes to their partition coefficient, which cannot be determined otherwise. This concept is especially interesting for protein-ligand complexes where the protein undergoes a conformational change, different from the CD/ASA complexes, giving rise to additional changes in their hydrophilicity.
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Affiliation(s)
- Doreen Niether
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH , D-52428 Jülich, Germany
| | | | - Jana Hovancová
- Chemistry Department, Pavol Jozef Šafárik Univerzity , 041 80 Košice, Slovakia
| | | | - Jan K G Dhont
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH , D-52428 Jülich, Germany
- Department of Physics, Heinrich-Heine-Universität Düsseldorf , D-40225 Düsseldorf, Germany
| | | | - Simone Wiegand
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH , D-52428 Jülich, Germany
- Department für Chemie-Physikalische Chemie, Universität zu Köln , D-50939 Cologne, Germany
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Stadler AM, Knieps-Grünhagen E, Bocola M, Lohstroh W, Zamponi M, Krauss U. Photoactivation Reduces Side-Chain Dynamics of a LOV Photoreceptor. Biophys J 2016; 110:1064-74. [PMID: 26958884 DOI: 10.1016/j.bpj.2016.01.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 01/08/2016] [Accepted: 01/20/2016] [Indexed: 11/17/2022] Open
Abstract
We used neutron-scattering experiments to probe the conformational dynamics of the light, oxygen, voltage (LOV) photoreceptor PpSB1-LOV from Pseudomonas putida in both the dark and light states. Global protein diffusion and internal macromolecular dynamics were measured using incoherent neutron time-of-flight and backscattering spectroscopy on the picosecond to nanosecond timescales. Global protein diffusion of PpSB1-LOV is not influenced by photoactivation. Observation-time-dependent global diffusion coefficients were found, which converge on the nanosecond timescale toward diffusion coefficients determined by dynamic light scattering. Mean-square displacements of localized internal motions and effective force constants, <k'>, describing the resilience of the proteins were determined on the respective timescales. Photoactivation significantly modifies the flexibility and the resilience of PpSB1-LOV. On the fast, picosecond timescale, small changes in the mean-square displacement and <k'> are observed, which are enhanced on the slower, nanosecond timescale. Photoactivation results in a slightly larger resilience of the photoreceptor on the fast, picosecond timescale, whereas in the nanosecond range, a significantly less resilient structure of the light-state protein is observed. For a residue-resolved interpretation of the experimental neutron-scattering data, we analyzed molecular dynamics simulations of the PpSB1-LOV X-ray structure. Based on these data, it is tempting to speculate that light-induced changes in the protein result in altered side-chain mobility mostly for residues on the protruding Jα helix and on the LOV-LOV dimer interface. Our results provide strong experimental evidence that side-chain dynamics play a crucial role in photoactivation and signaling of PpSB1-LOV via modulation of conformational entropy.
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Affiliation(s)
- Andreas M Stadler
- Jülich Centre for Neutron Science (JCNS) and Institute for Complex Systems (ICS), Forschungszentrum Jülich, Jülich, Germany.
| | - Esther Knieps-Grünhagen
- Institute of Molecular Enzyme Technology, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, Jülich, Germany
| | - Marco Bocola
- Chair of Biotechnology, RWTH Aachen University, Aachen, Germany
| | - Wiebke Lohstroh
- Heinz Maier-Leibnitz Zentrum, Technische Universität München, Garching, Germany
| | - Michaela Zamponi
- Jülich Centre for Neutron Science (JCNS), Outstation at MLZ, Forschungszentrum Jülich, Garching, Germany
| | - Ulrich Krauss
- Institute of Molecular Enzyme Technology, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, Jülich, Germany
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Fujiwara S, Araki K, Matsuo T, Yagi H, Yamada T, Shibata K, Mochizuki H. Dynamical Behavior of Human α-Synuclein Studied by Quasielastic Neutron Scattering. PLoS One 2016; 11:e0151447. [PMID: 27097022 PMCID: PMC4838215 DOI: 10.1371/journal.pone.0151447] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 02/29/2016] [Indexed: 12/02/2022] Open
Abstract
α-synuclein (αSyn) is a protein consisting of 140 amino acid residues and is abundant in the presynaptic nerve terminals in the brain. Although its precise function is unknown, the filamentous aggregates (amyloid fibrils) of αSyn have been shown to be involved in the pathogenesis of Parkinson's disease, which is a progressive neurodegenerative disorder. To understand the pathogenesis mechanism of this disease, the mechanism of the amyloid fibril formation of αSyn must be elucidated. Purified αSyn from bacterial expression is monomeric but intrinsically disordered in solution and forms amyloid fibrils under various conditions. As a first step toward elucidating the mechanism of the fibril formation of αSyn, we investigated dynamical behavior of the purified αSyn in the monomeric state and the fibril state using quasielastic neutron scattering (QENS). We prepared the solution sample of 9.5 mg/ml purified αSyn, and that of 46 mg/ml αSyn in the fibril state, both at pD 7.4 in D2O. The QENS experiments on these samples were performed using the near-backscattering spectrometer, BL02 (DNA), at the Materials and Life Science Facility at the Japan Accelerator Research Complex, Japan. Analysis of the QENS spectra obtained shows that diffusive global motions are observed in the monomeric state but largely suppressed in the fibril state. However, the amplitude of the side chain motion is shown to be larger in the fibril state than in the monomeric state. This implies that significant solvent space exists within the fibrils, which is attributed to the αSyn molecules within the fibrils having a distribution of conformations. The larger amplitude of the side chain motion in the fibril state than in the monomeric state implies that the fibril state is entropically favorable.
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Affiliation(s)
- Satoru Fujiwara
- Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai, Ibaraki, Japan
- * E-mail:
| | - Katsuya Araki
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Tatsuhito Matsuo
- Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai, Ibaraki, Japan
| | - Hisashi Yagi
- Center for Research on Green Sustainable Chemistry, Tottori University, Tottori, Japan
| | - Takeshi Yamada
- Research Center for Neutron Science and Technology, CROSS-Tokai, Tokai, Ibaraki, Japan
| | - Kaoru Shibata
- Neutron Science Section, J-PARC Center, Tokai, Ibaraki, Japan
| | - Hideki Mochizuki
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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Stadler AM, Demmel F, Ollivier J, Seydel T. Picosecond to nanosecond dynamics provide a source of conformational entropy for protein folding. Phys Chem Chem Phys 2016; 18:21527-38. [DOI: 10.1039/c6cp04146a] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Myoglobin can be trapped in fully folded structures, partially folded molten globules, and unfolded states under stable equilibrium conditions.
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Affiliation(s)
- Andreas M. Stadler
- Jülich Centre for Neutron Science JCNS and Institute for Complex Systems ICS
- Forschungszentrum Jülich GmbH
- 52425 Jülich
- Germany
| | | | | | - Tilo Seydel
- Institut Laue-Langevin
- 38042 Grenoble Cedex 9
- France
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Monkenbusch M, Stadler A, Biehl R, Ollivier J, Zamponi M, Richter D. Fast internal dynamics in alcohol dehydrogenase. J Chem Phys 2015; 143:075101. [DOI: 10.1063/1.4928512] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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