1
|
Reuhl M, Vogel M. Temperature-Dependent Dynamics at Protein-Solvent Interfaces. J Chem Phys 2022; 157:074705. [DOI: 10.1063/5.0105062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We perform differential scanning calorimetry, broadband dielectric spectroscopy (BDS), and nuclear magnetic resonance (NMR) studies to ascertain the molecular dynamics in mixtures of ethylene glycol with elastin or lysozyme over broad temperature ranges. To focus on the protein-solvent interface, we use mixtures with about equal numbers of amino acids and solvent molecules. The elastin and lysozyme mixtures show similar glass transition steps, which extend over a broad temperature range of 157-185K. The BDS and NMR studies yield fully consistent results for the fastest process P1, which is caused by the structural relaxation of ethylene glycol between the protein molecules and follows an Arrhenius law with an activation energy of Ea=0.63eV. It involves quasi-isotropic reorientation and is very similar in the elastin and lysozyme matrices but different from the alpha and beta relaxations of bulk ethylene glycol. Two slower BDS processes P2 and P3 have protein-dependent time scales, but exhibit a similar Arrhenius-like temperature dependence with an activation energy of Ea~0.81eV. However, P2 and P3 do not have a clear NMR signature. In particular, the NMR results for the lysozyme mixture reveal that the protein backbone does not show isotropic alpha-like motion on the P2 and P3 time scales but only restricted beta-like reorientation. The different activation energies of the P1 and P2/P3 processes do not support an intimate coupling of protein and ethylene glycol dynamics. The present results are compared with previous findings for mixtures of proteins with water or glycerol, implying qualitatively different dynamical couplings at various protein-solvent interfaces.
Collapse
Affiliation(s)
| | - Michael Vogel
- Institute of Condensed Matter Physics, TU Darmstadt, Germany
| |
Collapse
|
2
|
Roy P, Menon S, Sengupta N. Dynamical Manifestations of Supercooling in Amyloid Hydration. J Phys Chem B 2021; 126:44-53. [PMID: 34941279 DOI: 10.1021/acs.jpcb.1c07724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effect of extreme temperature on amyloidogenic species remains sparsely explored. In a recent study (J. Phys. Chem. Lett., 2019, 10, (10)), we employed exhaustive molecular dynamics simulations to explore the cold thermal response of a putative small amyloid oligomer and to elicit the role of solvent modulation. Herein, we investigate the dynamical response of the hydration waters of the oligomer within the supercooled states. Using NMR-based formalism, we delineate the entropic response in terms of the side-chain conformational entropy that corroborates the weakening of the hydrophobic core with lowering of temperature. The translational dynamics of the protein and hydration waters reveal the coupling of protein dynamical fluctuations with solvent dynamics under supercooled conditions. Probing the translational motion as a space-time correlation indicates glassy dynamics exhibited by hydration waters in the supercooled regime. Caging of the water molecules with lowering of temperature and the resultant hopping dynamics are reflected in the longer β-relaxation timescales of translational motion. Furthermore, we utilized mode-coupling theory (MCT) and derived the ideal glass transition temperature from translational and rotational dynamics, around ∼196 and 209 K, respectively. Interestingly, rotational motion in the supercooled regime deviates from the MCT law, exhibits Arrhenius motion, and marks a fragile-to-strong crossover at 227 K. The low-frequency vibrational modes also coincide with the dynamical transition. This exposition lends dynamical insights into the hydration coupling of an amyloid aggregate under cryogenic conditions.
Collapse
Affiliation(s)
- Priti Roy
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India 741246
| | - Sneha Menon
- Tata Institute of Fundamental Research Hyderabad, Telangana 500046, India
| | - Neelanjana Sengupta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India 741246
| |
Collapse
|
3
|
Evidence for an Ordering Transition near 120 K in an Intrinsically Disordered Protein, Casein. Molecules 2021; 26:molecules26195971. [PMID: 34641515 PMCID: PMC8512290 DOI: 10.3390/molecules26195971] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/25/2021] [Accepted: 09/29/2021] [Indexed: 11/16/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) are proteins that possess large unstructured regions. Their importance is increasingly recognized in biology but their characterization remains a challenging task. We employed field swept Electron Spin Echoes in pulsed EPR to investigate low-temperature stochastic molecular librations in a spin-labeled IDP, casein (the main protein of milk). For comparison, a spin-labeled globular protein, hen egg white lysozyme, is also investigated. For casein these motions were found to start at 100 K while for lysozyme only above 130 K, which was ascribed to a denser and more ordered molecular packing in lysozyme. However, above 120 K, the motions in casein were found to depend on temperature much slower than those in lysozyme. This abrupt change in casein was assigned to an ordering transition in which peptide residues rearrange making the molecular packing more rigid and/or more cohesive. The found features of molecular motions in these two proteins turned out to be very similar to those known for gel-phase lipid bilayers composed of conformationally ordered and conformationally disordered lipids. This analogy with a simpler molecular system may appear helpful for elucidation properties of molecular packing in IDPs.
Collapse
|
4
|
Kyrey T, Witte J, Lutzki J, Zamponi M, Wellert S, Holderer O. Mobility of bound water in PNIPAM microgels. Phys Chem Chem Phys 2021; 23:14252-14259. [PMID: 34159987 DOI: 10.1039/d1cp01823j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Polymer-solvent interactions play a crucial role in the stimuli-responsive behaviour of polymer networks. They influence the swelling/deswelling behaviour as well as the dynamics of the polymer chains. Scattering experiments provide insight into the polymer-water interaction of poly(N-isopropylacrylamide) (PNIPAM) microgels cross-linked with N,N'-methylenebisacrylamide (BIS) in dried and humidified state. The water mobility is studied by means of neutron spin-echo spectroscopy and neutron backscattering spectroscopy. The residual water amount has been determined with Karl Fischer titration. For both degrees of humidification, the relaxation time of the water molecules is much larger than that of free water due to the strong interactions with the polymer network and is only weakly depending on temperature and length scale of observation. The possible influence of the water on methyl group rotations is discussed.
Collapse
Affiliation(s)
- Tetyana Kyrey
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Garching, Germany.
| | - Judith Witte
- Technical University Berlin, Institute of Chemistry, Berlin, Germany
| | - Jana Lutzki
- Technical University Berlin, Institute of Chemistry, Berlin, Germany
| | - Michaela Zamponi
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Garching, Germany.
| | - Stefan Wellert
- Technical University Berlin, Institute of Chemistry, Berlin, Germany
| | - Olaf Holderer
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Garching, Germany.
| |
Collapse
|
5
|
Steinrücken E, Wissel T, Brodrecht M, Breitzke H, Regentin J, Buntkowsky G, Vogel M. 2H NMR study on temperature-dependent water dynamics in amino-acid functionalized silica nanopores. J Chem Phys 2021; 154:114702. [PMID: 33752372 DOI: 10.1063/5.0044141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We prepare various amino-acid functionalized silica pores with diameters of ∼6 nm and study the temperature-dependent reorientation dynamics of water in these confinements. Specifically, we link basic Lys, neutral Ala, and acidic Glu to the inner surfaces and combine 2H nuclear magnetic resonance spin-lattice relaxation and line shape analyses to disentangle the rotational motions of the surfaces groups and the crystalline and liquid water fractions coexisting below partial freezing. Unlike the crystalline phase, the liquid phase shows reorientation dynamics, which strongly depends on the chemistry of the inner surfaces. The water reorientation is slowest for the Lys functionalization, followed by Ala and Glu and, finally, the native silica pores. In total, the rotational correlation times of water at the different surfaces vary by about two orders of magnitude, where this span is largely independent of the temperature in the range ∼200-250 K.
Collapse
Affiliation(s)
- Elisa Steinrücken
- Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - Till Wissel
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| | - Martin Brodrecht
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| | - Hergen Breitzke
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| | - Julia Regentin
- Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - Gerd Buntkowsky
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| | - Michael Vogel
- Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| |
Collapse
|
6
|
Capaccioli S, Zheng L, Kyritsis A, Paciaroni A, Vogel M, Ngai KL. The Dynamics of Hydrated Proteins Are the Same as Those of Highly Asymmetric Mixtures of Two Glass-Formers. ACS OMEGA 2021; 6:340-347. [PMID: 33458485 PMCID: PMC7807739 DOI: 10.1021/acsomega.0c04655] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/08/2020] [Indexed: 05/31/2023]
Abstract
Customarily, the studies of dynamics of hydrated proteins are focused on the fast hydration water ν-relaxation, the slow structural α-relaxation responsible for a single glass transition, and the protein dynamic transition (PDT). Guided by the analogy with the dynamics of highly asymmetric mixtures of molecular glass-formers, we explore the possibility that the dynamics of hydrated proteins are richer than presently known. By providing neutron scattering, dielectric relaxation, calorimetry, and deuteron NMR data in two hydrated globular proteins, myoglobin and BSA, and the fibrous elastin, we show the presence of two structural α-relaxations, α1 and α2, and the hydration water ν-relaxation, all coupled together with interconnecting properties. There are two glass transition temperatures T g α1and T g α2 corresponding to vitrification of the α1 and α2 processes. Relaxation time τα2(T) of the α2-relaxation changes its Arrhenius temperature dependence to super-Arrhenius on crossing T g α1 from below. The ν-relaxation responds to the two vitrifications by changing the T-dependence of its relaxation time τν(T) on crossing consecutively T g α2 and T g α1. It generates the PDT at T d where τν(T d) matches about five times the experimental instrument timescale τexp, provided that T d > T g α1. This condition is satisfied by the hydrated globular proteins considered in this paper, and the ν-relaxation is in the liquid state with τν(T) having the super-Arrhenius temperature dependence. However, if T d < T g α1, the ν-relaxation fails to generate the PDT because it is in the glassy state and τν(T) has Arrhenius T-dependence, as in the case of hydrated elastin. Overall, the dynamics of hydrated proteins are the same as the dynamics of highly asymmetric mixtures of glass-formers. The results from this study have expanded the knowledge of the dynamic processes and their properties in hydrated proteins, and impact on research in this area is expected.
Collapse
Affiliation(s)
- Simone Capaccioli
- Dipartimento
di Fisica, Università di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy
- CNR-IPCF, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy
| | - Lirong Zheng
- School
of Physics and Astronomy, Shanghai Jiao
Tong University, Shanghai 200240, China
- Institute
of Natural Sciences, Shanghai Jiao Tong
University, Shanghai 200240, China
| | - Apostolos Kyritsis
- Department
of Physics, National Technical University
of Athens, 157 80 Athens, Greece
| | | | - Michael Vogel
- Institute
of Condensed Matter Physics, Technische
Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - Kia L. Ngai
- CNR-IPCF, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy
| |
Collapse
|
7
|
Confinement Effects on Glass-Forming Aqueous Dimethyl Sulfoxide Solutions. Molecules 2020; 25:molecules25184127. [PMID: 32917011 PMCID: PMC7570821 DOI: 10.3390/molecules25184127] [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: 08/11/2020] [Revised: 09/04/2020] [Accepted: 09/05/2020] [Indexed: 11/17/2022] Open
Abstract
Combining broadband dielectric spectroscopy and nuclear magnetic resonance studies, we analyze the reorientation dynamics and the translational diffusion associated with the glassy slowdown of the eutectic aqueous dimethyl sulfoxide solution in nano-sized confinements, explicitly, in silica pores with different diameters and in ficoll and lysozyme matrices at different concentrations. We observe that both rotational and diffusive dynamics are slower and more heterogeneous in the confinements than in the bulk but the degree of these effects depends on the properties of the confinement and differs for the components of the solution. For the hard and the soft matrices, the slowdown and the heterogeneity become more prominent when the size of the confinement is reduced. In addition, the dynamics are more retarded for dimethyl sulfoxide than for water, implying specific guest-host interactions. Moreover, we find that the temperature dependence of the reorientation dynamics and of the translational diffusion differs in severe confinements, indicating a breakdown of the Stokes–Einstein–Debye relation. It is discussed to what extent these confinement effects can be rationalized in the framework of core-shell models, which assume bulk-like and slowed-down motions in central and interfacial confinement regions, respectively.
Collapse
|