1
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Pouliquen DL. The biophysics of water in cell biology: perspectives on a keystone for both marine sciences and cancer research. Front Cell Dev Biol 2024; 12:1403037. [PMID: 38803391 PMCID: PMC11128620 DOI: 10.3389/fcell.2024.1403037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 04/29/2024] [Indexed: 05/29/2024] Open
Abstract
The biophysics of water, has been debated over more than a century. Although its importance is still underestimated, significant breakthroughs occurred in recent years. The influence of protein condensation on water availability control was documented, new findings on water-transport proteins emerged, and the way water molecules rearrange to minimize free energy at interfaces was deciphered, influencing membrane thermodynamics. The state of knowledge continued to progress in the field of deep-sea marine biology, highlighting unknown effects of high hydrostatic pressure and/or temperature on interactions between proteins and ligands in extreme environments, and membrane structure adaptations. The role of osmolytes in protein stability control under stress is also discussed here in relation to fish egg hydration/buoyancy. The complexity of water movements within the cell is updated, all these findings leading to a better view of their impact on many cellular processes. The way water flow and osmotic gradients generated by ion transport work together to produce the driving force behind cell migration is also relevant to both marine biology and cancer research. Additional common points concern water dynamic changes during the neoplastic transformation of cells and tissues, or embryo development. This could improve imaging techniques, early cancer diagnosis, and understanding of the molecular and physiological basis of buoyancy for many marine species.
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Affiliation(s)
- Daniel L. Pouliquen
- Inserm, CNRS, CRCINA, Nantes Université, University of Angers, Angers, France
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2
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Ritchhart A, Chen Z, Behera A, Jeon IR, Chapman KW, Vaikuntanathan S, Anderson JS. Cluster-Spin-Glass Magnetic Behavior and Morphology in the Coordination Polymer Alloys Fe yCo 1-yBTT. J Am Chem Soc 2023; 145:24089-24097. [PMID: 37876220 DOI: 10.1021/jacs.3c07527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
We report the synthesis of a series of pseudo-1D coordination polymer (CP) materials with the formula FeyCo1-yBTT (BTT = 1,3,5-benzenetrithiolate). These materials were structurally characterized by PXRD Rietveld, EXAFS, and PDF analyses, revealing that the CP superstructure enables a continuous and isomorphous alloy between the two homometallic compounds. Lower Fe loadings exhibit emergent spin glass magnetic behavior, such as memory effects and composition-dependent spin glass response time constants ranging from 6.9 × 10-9 s to 1.8 × 10-6 s. These data are consistent with the formation of spin clusters within the lattice. The magnetic behavior in these materials was modeled via replica exchange Monte Carlo simulation, which provides a good match for the experimentally measured spin glassing and magnetic phase transitions. These findings underscore how the rigid superstructure of CP and MOF scaffolds can enable the systematic tuning of physical properties, such as the spin glass behavior described here.
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Affiliation(s)
- Andrew Ritchhart
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Zhihengyu Chen
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | - Agnish Behera
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Ie-Rang Jeon
- Université de Rennes, Institut des Sciences Chimiques de Rennes, UMR CNRS 6226, 35042 Rennes, France
| | - Karena W Chapman
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | | | - John S Anderson
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
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3
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Plapp BV, Gakhar L, Subramanian R. Dependence of crystallographic atomic displacement parameters on temperature (25-150 K) for complexes of horse liver alcohol dehydrogenase. Acta Crystallogr D Struct Biol 2022; 78:1221-1234. [PMID: 36189742 PMCID: PMC9527765 DOI: 10.1107/s2059798322008361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 08/22/2022] [Indexed: 11/19/2022] Open
Abstract
Enzymes catalyze reactions by binding and orienting substrates with dynamic interactions. Horse liver alcohol dehydrogenase catalyzes hydrogen transfer with quantum-mechanical tunneling that involves fast motions in the active site. The structures and B factors of ternary complexes of the enzyme with NAD+ and 2,3,4,5,6-pentafluorobenzyl alcohol or NAD+ and 2,2,2-trifluoroethanol were determined to 1.1-1.3 Å resolution below the `glassy transition' in order to extract information about the temperature-dependent harmonic motions, which are reflected in the crystallographic B factors. The refinement statistics and structures are essentially the same for each structure at all temperatures. The B factors were corrected for a small amount of radiation decay. The overall B factors for the complexes are similar (13-16 Å2) over the range 25-100 K, but increase somewhat at 150 K. Applying TLS refinement to remove the contribution of pseudo-rigid-body displacements of coenzyme binding and catalytic domains provided residual B factors of 7-10 Å2 for the overall complexes and of 5-10 Å2 for C4N of NAD+ and the methylene carbon of the alcohols. These residual B factors have a very small dependence on temperature and include local harmonic motions and apparently contributions from other sources. Structures at 100 K show complexes that are poised for hydrogen transfer, which involves atomic displacements of ∼0.3 Å and is compatible with the motions estimated from the residual B factors and molecular-dynamics simulations. At 298 K local conformational changes are also involved in catalysis, as enzymes with substitutions of amino acids in the substrate-binding site have similar positions of NAD+ and pentafluorobenzyl alcohol and similar residual B factors, but differ by tenfold in the rate constants for hydride transfer.
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Affiliation(s)
- Bryce V. Plapp
- Department of Biochemistry and Molecular Biology, The University of Iowa, Iowa City, IA 52252, USA
| | - Lokesh Gakhar
- Protein and Crystallography Facility, Carver College of Medicine, The University of Iowa, Iowa City, IA 52252, USA
| | - Ramaswamy Subramanian
- Department of Biochemistry and Molecular Biology, The University of Iowa, Iowa City, IA 52252, USA
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4
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Novikov VN, Sokolov AP. Temperature Dependence of Structural Relaxation in Glass-Forming Liquids and Polymers. ENTROPY (BASEL, SWITZERLAND) 2022; 24:1101. [PMID: 36010765 PMCID: PMC9407199 DOI: 10.3390/e24081101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/05/2022] [Accepted: 08/07/2022] [Indexed: 06/15/2023]
Abstract
Understanding the microscopic mechanism of the transition of glass remains one of the most challenging topics in Condensed Matter Physics. What controls the sharp slowing down of molecular motion upon approaching the glass transition temperature Tg, whether there is an underlying thermodynamic transition at some finite temperature below Tg, what the role of cooperativity and heterogeneity are, and many other questions continue to be topics of active discussions. This review focuses on the mechanisms that control the steepness of the temperature dependence of structural relaxation (fragility) in glass-forming liquids. We present a brief overview of the basic theoretical models and their experimental tests, analyzing their predictions for fragility and emphasizing the successes and failures of the models. Special attention is focused on the connection of fast dynamics on picosecond time scales to the behavior of structural relaxation on much longer time scales. A separate section discusses the specific case of polymeric glass-forming liquids, which usually have extremely high fragility. We emphasize the apparent difference between the glass transitions in polymers and small molecules. We also discuss the possible role of quantum effects in the glass transition of light molecules and highlight the recent discovery of the unusually low fragility of water. At the end, we formulate the major challenges and questions remaining in this field.
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Affiliation(s)
- Vladimir N. Novikov
- Institute of Automation and Electrometry, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Alexei P. Sokolov
- Department of Chemistry and Joint Institute for Neutron Sciences, University of Tennessee, Knoxville, TN 37996, USA
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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5
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Matyushov DV. Conformational dynamics modulating electron transfer. J Chem Phys 2022; 157:095102. [DOI: 10.1063/5.0102707] [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
Diffusional dynamics of the donor-acceptor distance are responsible for the appearance of a new time scale of diffusion over the distance of electronic tunneling in electron-transfer reactions. The distance dynamics compete with the medium polarization dynamics in the dynamics-controlled electron-transfer kinetics. The pre-exponential factor of the electron-transfer rate constant switches, at the crossover distance, between a distance-independent, dynamics-controlled plateau and exponential distance decay. The crossover between two regimes is controlled by an effective relaxation time slowed down by a factor exponentially depending on the variance of the donor-acceptor displacement. Flexible donor-acceptor complexes must show a greater tendency for dynamics-controlled electron transfer. Energy chains based on electron transport are best designed by placing the redox cofactors near the crossover distance.
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Affiliation(s)
- Dmitry V. Matyushov
- Departments of Physics and School of Molecular Sciences, Arizona State University, United States of America
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6
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Stachowski TR, Vanarotti M, Seetharaman J, Lopez K, Fischer M. Water Networks Repopulate Protein-Ligand Interfaces with Temperature. Angew Chem Int Ed Engl 2022; 61:e202112919. [PMID: 35648650 PMCID: PMC9329195 DOI: 10.1002/anie.202112919] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Indexed: 12/14/2022]
Abstract
High-resolution crystal structures highlight the importance of water networks in protein-ligand interactions. However, as these are typically determined at cryogenic temperature, resulting insights may be structurally precise but not biologically accurate. By collecting 10 matched room-temperature and cryogenic datasets of the biomedical target Hsp90α, we identified changes in water networks that impact protein conformations at the ligand binding interface. Water repositioning with temperature repopulates protein ensembles and ligand interactions. We introduce Flipper conformational barcodes to identify temperature-sensitive regions in electron density maps. This revealed that temperature-responsive states coincide with ligand-responsive regions and capture unique binding signatures that disappear upon cryo-cooling. Our results have implications for discovering Hsp90 selective ligands, and, more generally, for the utility of hidden protein and water conformations in drug discovery.
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Affiliation(s)
- Timothy R. Stachowski
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTN 38105USA
| | - Murugendra Vanarotti
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTN 38105USA
| | - Jayaraman Seetharaman
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTN 38105USA
| | - Karlo Lopez
- School of Natural SciencesMathematicsand EngineeringCalifornia State UniversityBakersfieldCA 93311USA
| | - Marcus Fischer
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTN 38105USA
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTN 38105USA
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7
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Stachowski TR, Vanarotti M, Seetharaman J, Lopez K, Fischer M. Water Networks Repopulate Protein‐Ligand Interfaces With Temperature. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202112919] [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)
- Timothy R Stachowski
- St Jude Children's Research Hospital Chemical Biology & Therapeutics UNITED STATES
| | - Murugendra Vanarotti
- St Jude Children's Research Hospital Chemical Biology & Therapeutics UNITED STATES
| | | | - Karlo Lopez
- California State University - Bakersfield School of Natural Sciences, Mathematics, and Engineering UNITED STATES
| | - Marcus Fischer
- St. Jude Children's Research Hospital Chemical Biology & Therapeutics 262 Danny Thomas Place 38105 Memphis UNITED STATES
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8
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Busi B, Yarava JR, Bertarello A, Freymond F, Adamski W, Maurin D, Hiller M, Oschkinat H, Blackledge M, Emsley L. Similarities and Differences among Protein Dynamics Studied by Variable Temperature Nuclear Magnetic Resonance Relaxation. J Phys Chem B 2021; 125:2212-2221. [PMID: 33635078 DOI: 10.1021/acs.jpcb.0c10188] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Understanding and describing the dynamics of proteins is one of the major challenges in biology. Here, we use multifield variable-temperature NMR longitudinal relaxation (R1) measurements to determine the hierarchical activation energies of motions of four different proteins: two small globular proteins (GB1 and the SH3 domain of α-spectrin), an intrinsically disordered protein (the C-terminus of the nucleoprotein of the Sendai virus, Sendai Ntail), and an outer membrane protein (OmpG). The activation energies map the motions occurring in the side chains, in the backbone, and in the hydration shells of the proteins. We were able to identify similarities and differences in the average motions of the proteins. We find that the NMR relaxation properties of the four proteins do share similar features. The data characterizing average backbone motions are found to be very similar, the same for methyl group rotations, and similar activation energies are measured. The main observed difference occurs for the intrinsically disordered Sendai Ntail, where we observe much lower energy of activation for motions of protons associated with the protein-solvent interface as compared to the others. We also observe variability between the proteins regarding side chain 15N relaxation of lysine residues, with a higher activation energy observed in OmpG. This hints at strong interactions with negatively charged lipids in the bilayer and provides a possible mechanistic clue for the "positive-inside" rule for helical membrane proteins. Overall, these observations refine the understanding of the similarities and differences between hierarchical dynamics in proteins.
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Affiliation(s)
- Baptiste Busi
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Jayasubba Reddy Yarava
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin, Germany.,Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany
| | - Andrea Bertarello
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - François Freymond
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Wiktor Adamski
- Université Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | - Damien Maurin
- Université Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | - Matthias Hiller
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin, Germany.,Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany
| | - Hartmut Oschkinat
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin, Germany.,Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany
| | | | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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9
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Moreau DW, Atakisi H, Thorne RE. Solvent flows, conformation changes and lattice reordering in a cold protein crystal. Acta Crystallogr D Struct Biol 2019; 75:980-994. [PMID: 31692472 PMCID: PMC6834080 DOI: 10.1107/s2059798319013822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 10/10/2019] [Indexed: 11/10/2022] Open
Abstract
When protein crystals are abruptly cooled, the unit-cell, protein and solvent-cavity volumes all contract, but the volume of bulk-like internal solvent may expand. Outflow of this solvent from the unit cell and its accumulation in defective interior crystal regions has been suggested as one cause of the large increase in crystal mosaicity on cooling. It is shown that when apoferritin crystals are abruptly cooled to temperatures between 220 and 260 K, the unit cell contracts, solvent is pushed out and the mosaicity grows. On temperature-dependent timescales of 10 to 200 s, the unit-cell and solvent-cavity volume then expand, solvent flows back in, and the mosaicity and B factor both drop. Expansion and reordering at fixed low temperature are associated with small-amplitude but large-scale changes in the conformation and packing of apoferritin. These results demonstrate that increases in mosaicity on cooling arise due to solvent flows out of or into the unit cell and to incomplete, arrested relaxation of protein conformation. They indicate a critical role for time in variable-temperature crystallographic studies, and the feasibility of probing interactions and cooperative conformational changes that underlie cold denaturation in the presence of liquid solvent at temperatures down to ∼200 K.
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Affiliation(s)
- David W. Moreau
- Physics Department, Cornell University, Ithaca, NY 14853, USA
| | - Hakan Atakisi
- Physics Department, Cornell University, Ithaca, NY 14853, USA
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10
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Moreau DW, Atakisi H, Thorne RE. Ice formation and solvent nanoconfinement in protein crystals. IUCRJ 2019; 6:346-356. [PMID: 31098016 PMCID: PMC6503922 DOI: 10.1107/s2052252519001878] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 01/31/2019] [Indexed: 05/06/2023]
Abstract
Ice formation within protein crystals is a major obstacle to the cryocrystallographic study of protein structure, and has limited studies of how the structural ensemble of a protein evolves with temperature in the biophysically interesting range from ∼260 K to the protein-solvent glass transition near 200 K. Using protein crystals with solvent cavities as large as ∼70 Å, time-resolved X-ray diffraction was used to study the response of protein and internal solvent during rapid cooling. Solvent nanoconfinement suppresses freezing temperatures and ice-nucleation rates so that ice-free, low-mosaicity diffraction data can be reliably collected down to 200 K without the use of cryoprotectants. Hexagonal ice (Ih) forms in external solvent, but internal crystal solvent forms stacking-disordered ice (Isd) with a near-random stacking of cubic and hexagonal planes. Analysis of powder diffraction from internal ice and single-crystal diffraction from the host protein structure shows that the maximum crystallizable solvent fraction decreases with decreasing crystal solvent-cavity size, and that an ∼6 Å thick layer of solvent adjacent to the protein surface cannot crystallize. These results establish protein crystals as excellent model systems for the study of nanoconfined solvent. By combining fast cooling, intense X-ray beams and fast X-ray detectors, complete structural data sets for high-value targets, including membrane proteins and large complexes, may be collected at ∼220-240 K that have much lower mosaicities and comparable B factors, and that may allow more confident identification of ligand binding than in current cryocrystallographic practice.
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Affiliation(s)
- David W. Moreau
- Physics Department, Cornell University, Ithaca, NY 14853, USA
| | - Hakan Atakisi
- Physics Department, Cornell University, Ithaca, NY 14853, USA
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11
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Watanabe K, Kawai K, Nagoe A, Suzuki T, Oguni M. Multiple Glass-Transitions of Globular Protein BSA Aqueous Solutions Depending on the Hydration Degree. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2019. [DOI: 10.1246/bcsj.20180295] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Keisuke Watanabe
- Department of Chemistry, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
| | - Kiyoshi Kawai
- Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
| | - Atsushi Nagoe
- Department of Mathematics and Science, School of Science and Engineering, Kokushikan University, 4-28-1 Setagaya, Setagaya-ku, Tokyo 154-8515, Japan
| | - Toru Suzuki
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
| | - Masaharu Oguni
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
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12
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Busi B, Yarava JR, Hofstetter A, Salvi N, Cala-De Paepe D, Lewandowski JR, Blackledge M, Emsley L. Probing Protein Dynamics Using Multifield Variable Temperature NMR Relaxation and Molecular Dynamics Simulation. J Phys Chem B 2018; 122:9697-9702. [DOI: 10.1021/acs.jpcb.8b08578] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Baptiste Busi
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Jayasubba Reddy Yarava
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Albert Hofstetter
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Nicola Salvi
- Université Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | - Diane Cala-De Paepe
- Université de Lyon, Institut des Sciences Analytiques (UMR 5280 CNRS/UCBL/ENS Lyon), Centre de RMN à Très Hauts Champs, 69199 Villeurbanne, France
| | | | | | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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13
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Atakisi H, Moreau DW, Thorne RE. Effects of protein-crystal hydration and temperature on side-chain conformational heterogeneity in monoclinic lysozyme crystals. Acta Crystallogr D Struct Biol 2018; 74:264-278. [PMID: 29652254 PMCID: PMC5892876 DOI: 10.1107/s2059798318000207] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 01/03/2018] [Indexed: 01/12/2023] Open
Abstract
The modulation of main-chain and side-chain conformational heterogeneity and solvent structure in monoclinic lysozyme crystals by dehydration (related to water activity) and temperature is examined. Decreasing the relative humidity (from 99 to 11%) and decreasing the temperature both lead to contraction of the unit cell, to an increased area of crystal contacts and to remodeling of primarily contact and solvent-exposed residues. Both lead to the depopulation of some minor side-chain conformers and to the generation of new conformations. Side-chain modifications and main-chain r.m.s.d.s associated with cooling from 298 to 100 K depend on relative humidity and are minimized at 85% relative humidity (r.h.). Dehydration from 99 to 93% r.h. and cooling from 298 to 100 K result in a comparable number of remodeled residues, with dehydration-induced remodeling somewhat more likely to arise from contact interactions. When scaled to equivalent temperatures based on unit-cell contraction, the evolution of side-chain order parameters with dehydration shows generally similar features to those observed on cooling to T = 100 K. These results illuminate the qualitative and quantitative similarities between structural perturbations induced by modest dehydration, which routinely occurs in samples prepared for 298 and 100 K data collection, and cryocooling. Differences between these perturbations in terms of energy landscapes and occupancies, and implications for variable-temperature crystallography between 180 and 298 K, are discussed. It is also noted that remodeling of a key lysozyme active-site residue by dehydration, which is associated with a radical decrease in the enzymatic activity of lysozyme powder, arises due to a steric clash with the residue of a symmetry mate.
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Affiliation(s)
- Hakan Atakisi
- Physics Department, Cornell University, Ithaca, NY 14853, USA
| | - David W. Moreau
- Physics Department, Cornell University, Ithaca, NY 14853, USA
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14
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Grille Coronel L, Acierno JP, Ermácora MR. Ultracompact states of native proteins. Biophys Chem 2017; 230:36-44. [DOI: 10.1016/j.bpc.2017.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 08/16/2017] [Indexed: 10/19/2022]
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15
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Keedy DA, Kenner LR, Warkentin M, Woldeyes RA, Hopkins JB, Thompson MC, Brewster AS, Van Benschoten AH, Baxter EL, Uervirojnangkoorn M, McPhillips SE, Song J, Alonso-Mori R, Holton JM, Weis WI, Brunger AT, Soltis SM, Lemke H, Gonzalez A, Sauter NK, Cohen AE, van den Bedem H, Thorne RE, Fraser JS. Mapping the conformational landscape of a dynamic enzyme by multitemperature and XFEL crystallography. eLife 2015; 4. [PMID: 26422513 PMCID: PMC4721965 DOI: 10.7554/elife.07574] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 09/29/2015] [Indexed: 12/14/2022] Open
Abstract
Determining the interconverting conformations of dynamic proteins in atomic detail is a major challenge for structural biology. Conformational heterogeneity in the active site of the dynamic enzyme cyclophilin A (CypA) has been previously linked to its catalytic function, but the extent to which the different conformations of these residues are correlated is unclear. Here we compare the conformational ensembles of CypA by multitemperature synchrotron crystallography and fixed-target X-ray free-electron laser (XFEL) crystallography. The diffraction-before-destruction nature of XFEL experiments provides a radiation-damage-free view of the functionally important alternative conformations of CypA, confirming earlier synchrotron-based results. We monitored the temperature dependences of these alternative conformations with eight synchrotron datasets spanning 100-310 K. Multiconformer models show that many alternative conformations in CypA are populated only at 240 K and above, yet others remain populated or become populated at 180 K and below. These results point to a complex evolution of conformational heterogeneity between 180-–240 K that involves both thermal deactivation and solvent-driven arrest of protein motions in the crystal. The lack of a single shared conformational response to temperature within the dynamic active-site network provides evidence for a conformation shuffling model, in which exchange between rotamer states of a large aromatic ring in the middle of the network shifts the conformational ensemble for the other residues in the network. Together, our multitemperature analyses and XFEL data motivate a new generation of temperature- and time-resolved experiments to structurally characterize the dynamic underpinnings of protein function. DOI:http://dx.doi.org/10.7554/eLife.07574.001 Proteins are the workhorses of the cell. The shape that a protein molecule adopts enables it to carry out its role. However, a protein’s shape, or 'conformation', is not static. Instead, a protein can shift between different conformations. This is particularly true for enzymes – the proteins that catalyze chemical reactions. The region of an enzyme where the chemical reaction happens, known as the active site, often has to change its conformation to allow catalysis to proceed. Changes in temperature can also make a protein shift between alternative conformations. Understanding how a protein shifts between conformations gives insight into how it works. A common method for studying protein conformation is X-ray crystallography. This technique uses a beam of X-rays to figure out where the atoms of the protein are inside a crystal made of millions of copies of that protein. At room temperature or biological temperature, X-rays can rapidly damage the protein. Because of this, most crystal structures are determined at very low temperatures to minimize damage. But cooling to low temperatures changes the conformations that the protein adopts, and usually causes fewer conformations to be present. Keedy, Kenner, Warkentin, Woldeyes et al. have used X-ray crystallography from a very low temperature (-173°C or 100 K) to above room temperature (up to 27°C or 300 K) to explore the alternative conformations of an enzyme called cyclophilin A. These alternative conformations include those that have previously been linked to this enzyme’s activity. Starting at a low temperature, parts of the enzyme were seen to shift from having a single conformation to many conformations above a threshold temperature. Unexpectedly, different parts of the enzyme have different threshold temperatures, suggesting that there isn’t a single transition across the whole protein. Instead, it appears the way a protein’s conformation changes in response to temperature is more complex than was previously realized. This result suggests that conformations in different parts of a protein are coupled to each other in complex ways. Keedy, Kenner, Warkentin, Woldeyes et al. then performed X-ray crystallography at room temperature using an X-ray free-electron laser (XFEL). This technique can capture the protein’s structure before radiation damage occurs, and confirmed that the alternative conformations observed were not affected by radiation damage. The combination of X-ray crystallography at multiple temperatures, new analysis methods for identifying and measuring alternative conformations, and XFEL crystallography should help future studies to characterize conformational changes in other proteins. DOI:http://dx.doi.org/10.7554/eLife.07574.002
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Affiliation(s)
- Daniel A Keedy
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States
| | - Lillian R Kenner
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States
| | | | - Rahel A Woldeyes
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States
| | - Jesse B Hopkins
- Department of Physics, Cornell University, Ithaca, United States
| | - Michael C Thompson
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States
| | - Aaron S Brewster
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Andrew H Van Benschoten
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States
| | - Elizabeth L Baxter
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, United States
| | - Monarin Uervirojnangkoorn
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States.,Howard Hughes Medical Institute, Stanford University, Stanford, United States
| | - Scott E McPhillips
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, United States
| | - Jinhu Song
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, United States
| | - Roberto Alonso-Mori
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, United States
| | - James M Holton
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, United States.,Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, United States.,Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - William I Weis
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States.,Department of Structural Biology, Stanford University, Stanford, United States.,Department of Photon Science, SLAC National Accelerator Laboratory, Menlo Park, United States
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States.,Howard Hughes Medical Institute, Stanford University, Stanford, United States.,Department of Structural Biology, Stanford University, Stanford, United States.,Department of Photon Science, SLAC National Accelerator Laboratory, Menlo Park, United States
| | - S Michael Soltis
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, United States
| | - Henrik Lemke
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, United States
| | - Ana Gonzalez
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, United States
| | - Nicholas K Sauter
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Aina E Cohen
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, United States
| | - Henry van den Bedem
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, United States
| | - Robert E Thorne
- Department of Physics, Cornell University, Ithaca, United States
| | - James S Fraser
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States
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16
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Lewandowski JR, Halse ME, Blackledge M, Emsley L. Direct observation of hierarchical protein dynamics. Science 2015; 348:578-81. [DOI: 10.1126/science.aaa6111] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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17
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Amdursky N, Sepunaru L, Raichlin S, Pecht I, Sheves M, Cahen D. Electron Transfer Proteins as Electronic Conductors: Significance of the Metal and Its Binding Site in the Blue Cu Protein, Azurin. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2015; 2:1400026. [PMID: 27980928 PMCID: PMC5115354 DOI: 10.1002/advs.201400026] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 02/08/2015] [Indexed: 05/07/2023]
Abstract
Electron transfer (ET) proteins are biomolecules with specific functions, selected by evolution. As such they are attractive candidates for use in potential bioelectronic devices. The blue copper protein azurin (Az) is one of the most-studied ET proteins. Traditional spectroscopic, electrochemical, and kinetic methods employed for studying ET to/from the protein's Cu ion have been complemented more recently by studies of electrical conduction through a monolayer of Az in the solid-state, sandwiched between electrodes. As the latter type of measurement does not require involvement of a redox process, it also allows monitoring electronic transport (ETp) via redox-inactive Az-derivatives. Here, results of macroscopic ETp via redox-active and -inactive Az derivatives, i.e., Cu(II) and Cu(I)-Az, apo-Az, Co(II)-Az, Ni(II)-Az, and Zn(II)-Az are reported and compared. It is found that earlier reported temperature independence of ETp via Cu(II)-Az (from 20 K until denaturation) is unique, as ETp via all other derivatives is thermally activated at temperatures >≈200 K. Conduction via Cu(I)-Az shows unexpected temperature dependence >≈200 K, with currents decreasing at positive and increasing at negative bias. Taking all the data together we find a clear compensation effect of Az conduction around the Az denaturation temperature. This compensation can be understood by viewing the Az binding site as an electron trap, unless occupied by Cu(II), as in the native protein, with conduction of the native protein setting the upper transport efficiency limit.
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Affiliation(s)
- Nadav Amdursky
- Departments of Materials and Interfaces Weizmann Institute of Science Rehovot 76100 Israel; Departments of Organic Chemistry Weizmann Institute of Science Rehovot 76100 Israel
| | - Lior Sepunaru
- Departments of Materials and Interfaces Weizmann Institute of Science Rehovot 76100 Israel
| | - Sara Raichlin
- Departments of Materials and Interfaces Weizmann Institute of Science Rehovot 76100 Israel; Departments of Organic Chemistry Weizmann Institute of Science Rehovot 76100 Israel
| | - Israel Pecht
- Departments of Immunology Weizmann Institute of Science Rehovot 76100 Israel
| | - Mordechai Sheves
- Departments of Organic Chemistry Weizmann Institute of Science Rehovot 76100 Israel
| | - David Cahen
- Departments of Materials and Interfaces Weizmann Institute of Science Rehovot 76100 Israel
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18
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Xue Y, Skrynnikov NR. Ensemble MD simulations restrained via crystallographic data: accurate structure leads to accurate dynamics. Protein Sci 2015; 23:488-507. [PMID: 24452989 DOI: 10.1002/pro.2433] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 01/06/2014] [Accepted: 01/18/2014] [Indexed: 11/07/2022]
Abstract
Currently, the best existing molecular dynamics (MD) force fields cannot accurately reproduce the global free-energy minimum which realizes the experimental protein structure. As a result, long MD trajectories tend to drift away from the starting coordinates (e.g., crystallographic structures). To address this problem, we have devised a new simulation strategy aimed at protein crystals. An MD simulation of protein crystal is essentially an ensemble simulation involving multiple protein molecules in a crystal unit cell (or a block of unit cells). To ensure that average protein coordinates remain correct during the simulation, we introduced crystallography-based restraints into the MD protocol. Because these restraints are aimed at the ensemble-average structure, they have only minimal impact on conformational dynamics of the individual protein molecules. So long as the average structure remains reasonable, the proteins move in a native-like fashion as dictated by the original force field. To validate this approach, we have used the data from solid-state NMR spectroscopy, which is the orthogonal experimental technique uniquely sensitive to protein local dynamics. The new method has been tested on the well-established model protein, ubiquitin. The ensemble-restrained MD simulations produced lower crystallographic R factors than conventional simulations; they also led to more accurate predictions for crystallographic temperature factors, solid-state chemical shifts, and backbone order parameters. The predictions for (15) N R1 relaxation rates are at least as accurate as those obtained from conventional simulations. Taken together, these results suggest that the presented trajectories may be among the most realistic protein MD simulations ever reported. In this context, the ensemble restraints based on high-resolution crystallographic data can be viewed as protein-specific empirical corrections to the standard force fields.
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Affiliation(s)
- Yi Xue
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana, 47907-2084, USA
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19
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Monkos K. Determination of the glass-transition temperature of proteins from a viscometric approach. Int J Biol Macromol 2014; 74:1-4. [PMID: 25485943 DOI: 10.1016/j.ijbiomac.2014.11.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 08/29/2014] [Accepted: 11/27/2014] [Indexed: 11/17/2022]
Abstract
All fully hydrated proteins undergo a distinct change in their dynamical properties at glass-transition temperature Tg. To determine indirectly this temperature for dry albumins, the viscosity measurements of aqueous solutions of human, equine, ovine, porcine and rabbit serum albumin have been conducted at a wide range of concentrations and at temperatures ranging from 278 K to 318 K. Viscosity-temperature dependence of the solutions is discussed on the basis of the three parameters equation resulting from Avramov's model. One of the parameter in the Avramov's equation is the glass-transition temperature. For all studied albumins, Tg of a solution monotonically increases with increasing concentration. The glass-transition temperature of a solution depends both on Tg for a dissolved dry protein Tg,p and water Tg,w. To obtain Tg,p for each studied albumin the modified Gordon-Taylor equation was applied. This equation describes the dependence of Tg of a solution on concentration, and Tg,p and a parameter depending on the strength of the protein-solvent interaction are the fitting parameters. Thus determined the glass-transition temperature for the studied dry albumins is in the range (215.4-245.5)K.
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Affiliation(s)
- Karol Monkos
- Department of Biophysics, Medical University of Silesia, H. Jordana 19, 41-808 Zabrze 8, Poland.
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20
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Woods KN. The glassy state of crambin and the THz time scale protein-solvent fluctuations possibly related to protein function. BMC BIOPHYSICS 2014; 7:8. [PMID: 25184036 PMCID: PMC4143578 DOI: 10.1186/s13628-014-0008-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 08/04/2014] [Indexed: 11/17/2022]
Abstract
BACKGROUND THz experiments have been used to characterize the picosecond time scale fluctuations taking place in the model, globular protein crambin. RESULTS Using both hydration and temperature as an experimental parameter, we have identified collective fluctuations (<= 200 cm(-1)) in the protein. Observation of the protein dynamics in the THz spectrum from both below and above the glass transition temperature (Tg) has provided unique insight into the microscopic interactions and modes that permit the solvent to effectively couple to the protein thermal fluctuations. CONCLUSIONS Our findings suggest that the solvent dynamics on the picosecond time scale not only contribute to protein flexibility but may also delineate the types of fluctuations that are able to form within the protein structure.
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Affiliation(s)
- Kristina N Woods
- Physics Department, Carnegie Mellon University, Pittsburgh 15213, PA, USA
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21
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Chakraborty K, Bandyopadhyay S. Correlated Dynamical Crossovers of the Hydration Layer of a Single-Stranded DNA Oligomer. J Phys Chem B 2014; 118:413-22. [DOI: 10.1021/jp408234k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Kaushik Chakraborty
- Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
| | - Sanjoy Bandyopadhyay
- Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
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22
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Edwards DT, Zhang Y, Glaser SJ, Han S, Sherwin MS. Phase cycling with a 240 GHz, free electron laser-powered electron paramagnetic resonance spectrometer. Phys Chem Chem Phys 2013; 15:5707-19. [PMID: 23474874 DOI: 10.1039/c3cp44492a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron paramagnetic resonance (EPR) powered by a free electron laser (FEL) has been shown to dramatically expand the capabilities of EPR at frequencies above ~100 GHz, where other high-power sources are unavailable. High-power pulses are necessary to achieve fast (<10 ns) spin rotations in order to alleviate the limited excitation bandwidth and time resolution that typically hamper pulsed EPR at these high frequencies. While at these frequencies, an FEL is the only source that provides ~1 kW of power and can be tuned continuously up to frequencies above 1 THz, it has only recently been implemented for one- and two-pulse EPR, and the capabilities of the FEL as an EPR source are still being expanded. This manuscript presents phase cycling of two pulses in an FEL-EPR spectrometer operating at 240 GHz. Given that the FEL, unlike amplifiers, cannot be easily phase-locked to a reference source, we instead apply retrospective data processing to measure the relative phase of each FEL pulse in order to correct the signal phase accordingly. This allows the measured signal to be averaged coherently, and the randomly changing phase of the FEL pulse results in a stochastic phase cycle, which, in the limit of many pulses, efficiently cancels artifacts and improves sensitivity. Further, the relative phase between the first and second pulse, which originates from the difference in path length traversed by each pulse, can be experimentally measured without phase-sensitive detection. We show that the relative phase of the two pulses can be precisely tuned, as well as distinctly switched by a fixed amount, with the insertion of a dielectric material into the quasi-optical path of one of the pulses. Taken together, these techniques offer many of the advantages of arbitrary phase control, and allow application of phase cycling to dramatically enhance signal quality in pulsed EPR experiments utilizing high-power sources that cannot be phase-locked.
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Affiliation(s)
- Devin T Edwards
- Department of Physics, University of California, Santa Barbara, Santa Barbara, California 93106, USA.
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23
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Edwards DT, Ma Z, Meade TJ, Goldfarb D, Han S, Sherwin MS. Extending the distance range accessed with continuous wave EPR with Gd3+ spin probes at high magnetic fields. Phys Chem Chem Phys 2013; 15:11313-26. [PMID: 23732863 PMCID: PMC4142211 DOI: 10.1039/c3cp43787f] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Interspin distances between 0.8 nm and 2.0 nm can be measured through the dipolar broadening of the continuous wave (cw) EPR spectrum of nitroxide spin labels at X-band (9.4 GHz, 0.35 T). We introduce Gd(3+) as a promising alternative spin label for distance measurements by cw EPR above 7 Tesla, where the |-1/2〉 to |1/2〉 transition narrows below 1 mT and becomes extremely sensitive to dipolar broadening. To estimate the distance limits of cw EPR with Gd(3+), we have measured spectra of frozen solutions of GdCl3 at 8.6 T (240 GHz) and 10 K at concentrations ranging from 50 mM to 0.1 mM, covering a range of average interspin distances. These experiments show substantial dipolar broadening at distances where line broadening cannot be observed with nitroxides at X-band. This data, and its agreement with calculated dipolar-broadened lineshapes, show Gd(3+) to be sensitive to distances as long as ∼3.8 nm. Further, the linewidth of a bis-Gd(3+) complex with a flexible ∼1.6 nm bridge is strongly broadened as compared to the mono-Gd(3+) complex, demonstrating the potential for application to pairwise distances. Gd-DOTA-based chelates that can be functionalized to protein surfaces display linewidths narrower than aqueous GdCl3, implying they should be even more sensitive to dipolar broadening. Therefore, we suggest that the combination of tailored Gd(3+) labels and high magnetic fields can extend the longest interspin distances measurable by cw EPR from 2.0 nm to 3.8 nm. cw EPR data at 260 K demonstrate that the line broadening remains clear out to similar average interspin distances, offering Gd(3+) probes as promising distance rulers at temperatures higher than possible with conventional pulsed EPR distance measurements.
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Affiliation(s)
- Devin T. Edwards
- Department of Physics, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - Zhidong Ma
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
| | - Thomas J. Meade
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
- Department of Molecular Biosciences, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
- Department of Neurobiology & Physiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
- Department of Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
| | - Daniella Goldfarb
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Songi Han
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, USA
- Institute for Terahertz Science and Technology, Santa Barbara, California 93106, USA
| | - Mark S. Sherwin
- Department of Physics, University of California, Santa Barbara, Santa Barbara, California 93106, USA
- Institute for Terahertz Science and Technology, Santa Barbara, California 93106, USA
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24
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Abaturov LV, Nosova NG. Protein conformational dynamics of crambin in crystal, solution and in the trajectories of molecular dynamics simulations. Biophysics (Nagoya-shi) 2013. [DOI: 10.1134/s0006350913040027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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25
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Gregory MJ, Anderson M, Causgrove TP. Measurement of energy barriers to conformational change in poly-l-glutamic acid by temperature-derivative spectroscopy. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2013.04.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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26
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Structural basis for ion permeation mechanism in pentameric ligand-gated ion channels. EMBO J 2013; 32:728-41. [PMID: 23403925 PMCID: PMC3590989 DOI: 10.1038/emboj.2013.17] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 01/07/2013] [Indexed: 12/14/2022] Open
Abstract
To understand the molecular mechanism of ion permeation in pentameric ligand-gated ion channels (pLGIC), we solved the structure of an open form of GLIC, a prokaryotic pLGIC, at 2.4 Å. Anomalous diffraction data were used to place bound anions and cations. This reveals ordered water molecules at the level of two rings of hydroxylated residues (named Ser6' and Thr2') that contribute to the ion selectivity filter. Two water pentagons are observed, a self-stabilized ice-like water pentagon and a second wider water pentagon, with one sodium ion between them. Single-channel electrophysiology shows that the side-chain hydroxyl of Ser6' is crucial for ion translocation. Simulations and electrostatics calculations complemented the description of hydration in the pore and suggest that the water pentagons observed in the crystal are important for the ion to cross hydrophobic constriction barriers. Simulations that pull a cation through the pore reveal that residue Ser6' actively contributes to ion translocation by reorienting its side chain when the ion is going through the pore. Generalization of these findings to the pLGIC family is proposed.
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27
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Warkentin M, Hopkins JB, Badeau R, Mulichak AM, Keefe LJ, Thorne RE. Global radiation damage: temperature dependence, time dependence and how to outrun it. JOURNAL OF SYNCHROTRON RADIATION 2013; 20:7-13. [PMID: 23254651 PMCID: PMC3526918 DOI: 10.1107/s0909049512048303] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 11/25/2012] [Indexed: 05/22/2023]
Abstract
A series of studies that provide a consistent and illuminating picture of global radiation damage to protein crystals, especially at temperatures above ∼200 K, are described. The radiation sensitivity shows a transition near 200 K, above which it appears to be limited by solvent-coupled diffusive processes. Consistent with this interpretation, a component of global damage proceeds on timescales of several minutes at 180 K, decreasing to seconds near room temperature. As a result, data collection times of order 1 s allow up to half of global damage to be outrun at 260 K. Much larger damage reductions near room temperature should be feasible using larger dose rates delivered using microfocused beams, enabling a significant expansion of structural studies of proteins under more nearly native conditions.
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Affiliation(s)
| | | | - Ryan Badeau
- Physics Department, Cornell University, Ithaca, NY 14853, USA
| | | | - Lisa J. Keefe
- IMCA-CAT, Argonne National Laboratory, Argonne, IL 60439, USA
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28
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Marked changes in electron transport through the blue copper protein azurin in the solid state upon deuteration. Proc Natl Acad Sci U S A 2012; 110:507-12. [PMID: 23267087 DOI: 10.1073/pnas.1210457110] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Measuring solid-state electron transport (ETp) across proteins allows studying electron transfer (ET) mechanism(s), while minimizing solvation effects on the process. ETp is, however, sensitive to any static (conformational) or dynamic (vibrational) changes in the protein. Our macroscopic measurements allow extending ETp studies to low temperatures, with the concomitant resolution of lower current densities, because of the larger electrode contact areas. Thus, earlier we reported temperature-independent ETp via the copper protein azurin (Az), from 80 K until denaturation, whereas for apo-Az ETp was temperature dependent above 180 K. Deuteration (H/D substitution) may provide mechanistic information on the question of whether the ETp involves H-bonds in the solid state. Here we report results of kinetic deuterium isotope effect (KIE) measurements on ETp through holo-Az as a function of temperature (30-340 K). Strikingly, deuteration changed ETp from temperature independent to temperature dependent above 180 K. This H/D effect is expressed in KIE values between 1.8 (340 K) and 9.1 (≤ 180 K). These values are remarkable in light of the previously reported inverse KIE on ET in Az in solution. We ascribe the difference between our KIE results and those observed in solution to the dominance of solvent effects in the latter (larger thermal expansion in H(2)O than in D(2)O), whereas in our case the KIE is primarily due to intramolecular changes, mainly in the low-frequency structural modes of the protein caused by H/D exchange. The observed high KIE values are consistent with a transport mechanism that involves through-H-bonds of the β-sheet structure of Az, likely also those in the Cu coordination sphere.
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29
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Vogelsberg CS, Bracco S, Beretta M, Comotti A, Sozzani P, Garcia-Garibay MA. Dynamics of molecular rotors confined in two dimensions: transition from a 2D rotational glass to a 2D rotational fluid in a periodic mesoporous organosilica. J Phys Chem B 2012; 116:1623-32. [PMID: 22220838 DOI: 10.1021/jp2119263] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The motional behavior of p-phenylene-d(4) rotators confined within the 2D layers of a hierarchically ordered periodic mesoporous p-divinylbenzenesilica has been elucidated to evaluate the effects of reduced dimensionality on the engineered dynamics of artificial molecular machines. The hybrid mesoporous material, characterized by a honeycomb lattice structure, has arrays of alternating p-divinylbenzene rotors and siloxane layers forming the molecularly ordered walls of the mesoscopic channels. The p-divinylbenzene rotors are strongly anchored between two adjacent siloxane sheets, so that the p-phenylene rotators are unable to experience translational diffusion and are allowed to rotate about only one fixed axis. Variable-temperature (2)H NMR experiments revealed that the p-phenylene rotators undergo an exchange process between sites related by 180° and a non-Arrhenius temperature dependence of the dynamics, with reorientational rates ranging from 10(3) to 10(8) Hz between 215 to 305 K. The regime of motion changes rapidly at about 280 K indicating the occurrence of a dynamical transition. The transition was also recognized by a steep change in the heat capacity at constant pressure. As a result of the robust lamellar architecture comprising the pore walls, the orientational dynamic disorder related to the phase transition is only realized in two dimensions within the layers, that is in the plane perpendicular to the channel axis. Thus, the aligned rotors that form the organic layers exhibit unique anisotropic dynamical properties as a result of the architecture's reduced dimensionality. The dynamical disorder restricted to two dimensions constitutes a highly mobile fluidlike rotational phase at room temperature, which upon cooling undergoes a transition to a more rigid glasslike phase. Activation energies of 5.9 and 9.5 kcal/mol respectively have been measured for the two dynamical regimes of rotation. Collectively, our investigation has led to the discovery of an orientationally disordered 2D rotational glass and its transition from rigid to soft at increasing temperature. The spectral narrowing observed in the (2)H NMR experiments at higher temperatures (310-420 K) is consistent with fast rotational dynamics, which remain anisotropic in nature within the robust lamellar architecture. This study suggests that exploiting reduced dimensionality in the design of solid-state artificial molecular machines and functional materials may yield access to behavior previously unrealized in 3D materials.
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Affiliation(s)
- Cortnie S Vogelsberg
- Department of Chemistry, University of California - Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095, USA
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Abstract
Proteins are known to undergo a dynamical transition at around 200 K but the underlying mechanism, physical origin, and relationship to water are controversial. Here we report an observation of a protein dynamical transition as low as 110 K. This unexpected protein dynamical transition precisely correlated with the cryogenic phase transition of water from a high-density amorphous to a low-density amorphous state. The results suggest that the cryogenic protein dynamical transition might be directly related to the two liquid forms of water proposed at cryogenic temperatures.
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Howard EI, Blakeley MP, Haertlein M, Petit-Haertlein I, Mitschler A, Fisher SJ, Cousido-Siah A, Salvay AG, Popov A, Muller-Dieckmann C, Petrova T, Podjarny A. Neutron structure of type-III antifreeze protein allows the reconstruction of AFP-ice interface. J Mol Recognit 2011; 24:724-32. [PMID: 21472814 DOI: 10.1002/jmr.1130] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Antifreeze proteins (AFPs) inhibit ice growth at sub-zero temperatures. The prototypical type-III AFPs have been extensively studied, notably by X-ray crystallography, solid-state and solution NMR, and mutagenesis, leading to the identification of a compound ice-binding surface (IBS) composed of two adjacent ice-binding sections, each which binds to particular lattice planes of ice crystals, poisoning their growth. This surface, including many hydrophobic and some hydrophilic residues, has been extensively used to model the interaction of AFP with ice. Experimentally observed water molecules facing the IBS have been used in an attempt to validate these models. However, these trials have been hindered by the limited capability of X-ray crystallography to reliably identify all water molecules of the hydration layer. Due to the strong diffraction signal from both the oxygen and deuterium atoms, neutron diffraction provides a more effective way to determine the water molecule positions (as D(2) O). Here we report the successful structure determination at 293 K of fully perdeuterated type-III AFP by joint X-ray and neutron diffraction providing a very detailed description of the protein and its solvent structure. X-ray data were collected to a resolution of 1.05 Å, and neutron Laue data to a resolution of 1.85 Å with a "radically small" crystal volume of 0.13 mm(3). The identification of a tetrahedral water cluster in nuclear scattering density maps has allowed the reconstruction of the IBS-bound ice crystal primary prismatic face. Analysis of the interactions between the IBS and the bound ice crystal primary prismatic face indicates the role of the hydrophobic residues, which are found to bind inside the holes of the ice surface, thus explaining the specificity of AFPs for ice versus water.
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Affiliation(s)
- Eduardo I Howard
- IFLYSIB, UNLP-CONICET, Calle 59, 789, B1900BTE, La Plata, Argentina.
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Wang X, Xu X, Ma Z, Huo Y, Xiao Z, Li Y, Wang Y. Dynamic mechanisms for pre-miRNA binding and export by Exportin-5. RNA (NEW YORK, N.Y.) 2011; 17:1511-28. [PMID: 21712399 PMCID: PMC3153975 DOI: 10.1261/rna.2732611] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The biogenesis and function of mature microRNAs (miRNAs) is dependent on the nuclear export of miRNA precursors (pre-miRNA) by Exportin-5 (Exp5). To characterize the molecular mechanisms of how pre-miRNA is recognized and transported by Exp5, we have performed 21 molecular dynamic (MD) simulations of RNA-bound Exp5 (Exp5-RanGTP-premiRNA, Exp5-RanGDP-premiRNA, Exp5-premiRNA), RNA-unbound Exp5 (Exp5-RanGTP, Exp5-RanGDP, apo-Exp5), and pre-miRNA. Our simulations with standard MD, steered molecular dynamics (SMD), and energy analysis have shown that (1) Free Exp5 undergoes extensive opening motion, and in this way facilitates the RanGTP binding. (2) RanGTP efficiently regulates the association/dissociation of pre-miRNA to its complex by inducing conformational changes in the HEAT-repeat helix stacking of Exp5. (3) The GTP hydrolysis prevents Ran from rebinding to Exp5 by regulating the hydrophobic interfaces and salt bridges between Ran and Exp5. (4) The transition from the A'-form to the A-form of the pre-miRNA modulates the structural complementarities between the protein and the pre-miRNA, thus promoting efficient assembly of the complex. (5) The base-flipping process (from the closed to the fully flipped state) of the 2-nt 3' overhang is a prerequisite for the pre-miRNA recognition by Exp5, which occurs in a sequence-independent manner as evidenced by the fact that different 2-nt 3' overhangs bind to Exp5 in essentially the same way. And finally, a plausible mechanism of the pre-miRNA export cycle has been proposed explaining how the protein-protein and protein-RNA interactions are coordinated in physiological conditions.
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Affiliation(s)
- Xia Wang
- Center of Bioinformatics, Northwest A&F University, Yangling 712100, Shaanxi, China
- College of Life Sciences, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Xue Xu
- Center of Bioinformatics, Northwest A&F University, Yangling 712100, Shaanxi, China
- College of Life Sciences, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Zhi Ma
- Center of Bioinformatics, Northwest A&F University, Yangling 712100, Shaanxi, China
- College of Life Sciences, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Yingqiu Huo
- College of Information Engineering, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Zhengtao Xiao
- Center of Bioinformatics, Northwest A&F University, Yangling 712100, Shaanxi, China
- College of Life Sciences, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Yan Li
- Department of Materials Science and Chemical Engineering, Dalian University of Technology, Dalian 116023, Liaoning, China
| | - Yonghua Wang
- Center of Bioinformatics, Northwest A&F University, Yangling 712100, Shaanxi, China
- College of Life Sciences, Northwest A&F University, Yangling 712100, Shaanxi, China
- Corresponding author.E-mail
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Niss K, Dalle-Ferrier C, Frick B, Russo D, Dyre J, Alba-Simionesco C. Connection between slow and fast dynamics of molecular liquids around the glass transition. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 82:021508. [PMID: 20866819 DOI: 10.1103/physreve.82.021508] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 06/01/2010] [Indexed: 05/29/2023]
Abstract
The mean-square displacement (MSD) was measured by neutron scattering at various temperatures and pressures for a number of molecular glass-forming liquids. The MSD is invariant along the glass-transition line at the pressure studied, thus establishing an "intrinsic" Lindemann criterion for any given liquid. A one-to-one connection between the MSD's temperature dependence and the liquid's fragility is found when the MSD is evaluated on a time scale of ∼4 ns , but does not hold when the MSD is evaluated at shorter times. The findings are discussed in terms of the elastic model and the role of relaxations, and the correlations between slow and fast dynamics are addressed.
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Weik M, Colletier JP. Temperature-dependent macromolecular X-ray crystallography. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2010; 66:437-46. [PMID: 20382997 PMCID: PMC2852308 DOI: 10.1107/s0907444910002702] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 01/21/2010] [Indexed: 11/10/2022]
Abstract
X-ray crystallography provides structural details of biological macromolecules. Whereas routine data are collected close to 100 K in order to mitigate radiation damage, more exotic temperature-controlled experiments in a broader temperature range from 15 K to room temperature can provide both dynamical and structural insights. Here, the dynamical behaviour of crystalline macromolecules and their surrounding solvent as a function of cryo-temperature is reviewed. Experimental strategies of kinetic crystallography are discussed that have allowed the generation and trapping of macromolecular intermediate states by combining reaction initiation in the crystalline state with appropriate temperature profiles. A particular focus is on recruiting X-ray-induced changes for reaction initiation, thus unveiling useful aspects of radiation damage, which otherwise has to be minimized in macromolecular crystallography.
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Affiliation(s)
- Martin Weik
- CEA, IBS, Laboratoire de Biophysique Moléculaire, F-38054 Grenoble, France.
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35
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Glass DC, Krishnan M, Nutt DR, Smith JC. Temperature Dependence of Protein Dynamics Simulated with Three Different Water Models. J Chem Theory Comput 2010. [DOI: 10.1021/ct9006508] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dennis C. Glass
- University of Tennessee/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, and Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, United Kingdom
| | - Marimuthu Krishnan
- University of Tennessee/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, and Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, United Kingdom
| | - David R. Nutt
- University of Tennessee/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, and Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, United Kingdom
| | - Jeremy C. Smith
- University of Tennessee/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, and Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, United Kingdom
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36
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Kealley C, Sokolova A, Kearley G, Kemner E, Russina M, Faraone A, Hamilton W, Gilbert E. Dynamical transition in a large globular protein: Macroscopic properties and glass transition. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1804:34-40. [DOI: 10.1016/j.bbapap.2009.06.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 06/12/2009] [Accepted: 06/29/2009] [Indexed: 10/20/2022]
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37
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Warkentin M, Thorne RE. Slow cooling and temperature-controlled protein crystallography. ACTA ACUST UNITED AC 2009; 11:85-9. [PMID: 20012211 DOI: 10.1007/s10969-009-9074-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 11/23/2009] [Indexed: 11/29/2022]
Abstract
In cryocrystallography, rapid sample cooling is generally deemed essential to prevent solvent crystallization and associated sample damage. We show that by carefully and completely removing all external solvent, many protein crystals can be successfully cooled to T = 100 K at only 0.1 K/s without additional penetrating cryoprotectants. Slow cooling provides an alternative when flash cooling fails, and enables diffraction studies of protein structure and function at all temperatures between T = 300 K and T = 100 K.
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38
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Meersman F, Bowron D, Soper AK, Koch MHJ. Counteraction of urea by trimethylamine N-oxide is due to direct interaction. Biophys J 2009; 97:2559-66. [PMID: 19883599 PMCID: PMC2770612 DOI: 10.1016/j.bpj.2009.08.017] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 08/12/2009] [Accepted: 08/13/2009] [Indexed: 10/20/2022] Open
Abstract
Trimethylamine N-oxide (TMAO) is a naturally occurring osmolyte that stabilizes proteins, induces folding, and counteracts the denaturing effects of urea, pressure, and ice. To establish the mechanism behind these effects, isotopic substitution neutron-scattering measurements were performed on aqueous solutions of TMAO and 1:1 TMAO-urea at a solute mole fraction of 0.05. The partial pair distribution functions were extracted using the empirical potential structure refinement method. The results were compared with previous results obtained with isosteric tert-butanol, as well as the available data from spectroscopy and molecular-dynamics simulations. In solution, the oxygen atom of TMAO is strongly hydrogen-bonded to, on average, between two and three water molecules, and the hydrogen-bond network is tighter in water than in pure water. In TMAO-urea solutions, the oxygen atom in TMAO preferentially forms hydrogen bonds with urea. This explains why the counteraction is completed at a 2:1 urea/TMAO concentration ratio, independently of urea concentration. These results strongly support models for the effect of TMAO on the stability of proteins based on a modification of the simultaneous equilibria that control hydrogen bonding between the peptide backbone and water or intramolecular sites, without any need for direct interaction between TMAO and the protein.
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Affiliation(s)
- Filip Meersman
- Department of Chemistry, Katholieke Universiteit Leuven, Leuven, Belgium.
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39
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Shinyashiki N, Yamamoto W, Yokoyama A, Yoshinari T, Yagihara S, Kita R, Ngai KL, Capaccioli S. Glass Transitions in Aqueous Solutions of Protein (Bovine Serum Albumin). J Phys Chem B 2009; 113:14448-56. [DOI: 10.1021/jp905511w] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Naoki Shinyashiki
- Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan, Naval Research Laboratory, Washington, D.C. 20375-5320, and Dipartimento di Fisica, Università di Pisa and polyLab, CNR-INFM, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
| | - Wataru Yamamoto
- Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan, Naval Research Laboratory, Washington, D.C. 20375-5320, and Dipartimento di Fisica, Università di Pisa and polyLab, CNR-INFM, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
| | - Ayame Yokoyama
- Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan, Naval Research Laboratory, Washington, D.C. 20375-5320, and Dipartimento di Fisica, Università di Pisa and polyLab, CNR-INFM, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
| | - Takeo Yoshinari
- Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan, Naval Research Laboratory, Washington, D.C. 20375-5320, and Dipartimento di Fisica, Università di Pisa and polyLab, CNR-INFM, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
| | - Shin Yagihara
- Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan, Naval Research Laboratory, Washington, D.C. 20375-5320, and Dipartimento di Fisica, Università di Pisa and polyLab, CNR-INFM, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
| | - Rio Kita
- Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan, Naval Research Laboratory, Washington, D.C. 20375-5320, and Dipartimento di Fisica, Università di Pisa and polyLab, CNR-INFM, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
| | - K. L. Ngai
- Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan, Naval Research Laboratory, Washington, D.C. 20375-5320, and Dipartimento di Fisica, Università di Pisa and polyLab, CNR-INFM, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
| | - Simone Capaccioli
- Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan, Naval Research Laboratory, Washington, D.C. 20375-5320, and Dipartimento di Fisica, Università di Pisa and polyLab, CNR-INFM, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
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40
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Warkentin M, Thorne RE. Slow cooling of protein crystals. J Appl Crystallogr 2009; 42:944-952. [PMID: 19798409 DOI: 10.1107/s0021889809023553] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Accepted: 06/19/2009] [Indexed: 11/10/2022] Open
Abstract
Cryoprotectant-free thaumatin crystals have been cooled from 300 to 100 K at a rate of 0.1 K s(-1) - 10(3)-10(4) times slower than in conventional flash cooling - while continuously collecting X-ray diffraction data, so as to follow the evolution of protein lattice and solvent properties during cooling. Diffraction patterns show no evidence of crystalline ice at any temperature. This indicates that the lattice of protein molecules is itself an excellent cryoprotectant, and with sodium potassium tartrate incorporated from the 1.5 M mother liquor ice nucleation rates are at least as low as in a 70% glycerol solution. Crystal quality during slow cooling remains high, with an average mosaicity at 100 K of 0.2 degrees . Most of the mosaicity increase occurs above approximately 200 K, where the solvent is still liquid, and is concurrent with an anisotropic contraction of the unit cell. Near 180 K a crossover to solid-like solvent behavior occurs, and on further cooling there is no additional degradation of crystal order. The variation of B factor with temperature shows clear evidence of a protein dynamical transition near 210 K, and at lower temperatures the slope dB/dT is a factor of 3-6 smaller than has been reported for any other protein. These results establish the feasibility of fully temperature controlled studies of protein structure and dynamics between 300 and 100 K.
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41
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Bajaj VS, van der Wel PC, Griffin RG. Observation of a low-temperature, dynamically driven structural transition in a polypeptide by solid-state NMR spectroscopy. J Am Chem Soc 2009; 131:118-28. [PMID: 19067520 PMCID: PMC2651395 DOI: 10.1021/ja8045926] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
At reduced temperatures, proteins and other biomolecules are generally found to exhibit dynamic as well as structural transitions. This includes a so-called protein glass transition that is universally observed in systems cooled between 200 and 230 K, and which is generally attributed to interactions between hydrating solvent molecules and protein side chains. However, there is also experimental and theoretical evidence for a low-temperature transition in the intrinsic dynamics of the protein itself, absent any solvent. Here, we use low-temperature solid-state NMR to examine site-specific fluctuations in atomic structure and dynamics in the absence of solvents. In particular, we employ magic angle spinning NMR to examine a structural phase transition associated with dynamic processes in a solvent-free polypeptide, N-f-MLF-OH, lattice at temperatures as low as 90 K. This transition is characterized by the appearance of an extra set of lines in 1D (15)N spectra as well as additional cross peaks in 2D (13)C-(13)C and (13)C-(15)N spectra. Interestingly, the gradual, temperature-dependent appearance of the new spectral component is not accompanied by the line broadening typical of dynamic transitions. A direct comparison between the spectra of N-f-MLF-OH and the analog N-f-MLF-OMe, which does not display this transition, indicates a correlation of the structural transition to the temperature dependent motion of the aromatic phenylalanine side chain. Several quantitative solid state NMR experiments were employed to provide site-specific measurements of structural and motional features of the observed transition.
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Affiliation(s)
| | | | - Robert G. Griffin
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
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42
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Verma PK, Makhal A, Mitra RK, Pal SK. Role of solvation dynamics in the kinetics of solvolysis reactions in microreactors. Phys Chem Chem Phys 2009; 11:8467-76. [DOI: 10.1039/b905573h] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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Sarangapani P, Zhao J, Zhu Y. How does sensitivity to dynamical heterogeneity in supercooled colloidal liquids depend on tracer size? J Chem Phys 2008; 129:104514. [DOI: 10.1063/1.2976770] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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44
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Hydration dynamics in a partially denatured ensemble of the globular protein human alpha-lactalbumin investigated with molecular dynamics simulations. Biophys J 2008; 95:5257-67. [PMID: 18775960 DOI: 10.1529/biophysj.108.136531] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Atomistic molecular dynamics simulations are used to probe changes in the nature and subnanosecond dynamical behavior of solvation waters that accompany partial denaturation of the globular protein, human alpha-lactalbumin. A simulated ensemble of subcompact conformers, similar to the molten globule state of human alpha-lactalbumin, demonstrates a marginal increase in the amount of surface solvation relative to the native state. This increase is accompanied by subtle but distinct enhancement in surface water dynamics, less favorable protein-water interactions, and a marginal decrease in the anomalous behavior of solvation water dynamics. The extent of solvent influx is not proportional to the increased surface area, and the partially denatured conformers are less uniformly solvated compared to their native counterpart. The observed solvation in partially denatured conformers is lesser in extent compared to earlier experimental estimates in molten globule states, and is consistent with more recent descriptions based on nuclear magnetic relaxation dispersion studies.
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45
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Quantitative fluorescence correlation spectroscopy reveals a 1000-fold increase in lifetime of protein functionality. Biophys J 2008; 95:3439-46. [PMID: 18586843 DOI: 10.1529/biophysj.108.133215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have investigated dilute protein solutions with fluorescence correlation spectroscopy (FCS) and have observed that a rapid loss of proteins occurs from solution. It is commonly assumed that such a loss is the result of protein adsorption to interfaces. A protocol was developed in which this mode of protein loss can be prevented. However, FCS on fluorescent protein (enhanced green fluorescent protein, mCherry, and mStrawberry) solutions enclosed by adsorption-protected interfaces still reveals a decrease of the fluorescent protein concentration, while the diffusion time is stable over long periods of time. We interpret this decay as a loss of protein functionality, probably caused by denaturation of the fluorescent proteins. We show that the typical lifetime of protein functionality in highly dilute, approximately single molecule per femtoliter solutions can be extended more than 1000-fold (typically from a few hours to >40 days) by adding compounds with surfactant behavior. No direct interactions between the surfactant and the fluorescent proteins were observed from the diffusion time measured by FCS. A critical surfactant concentration of more than 23 muM was required to achieve the desired protein stabilization for Triton X-100. The surfactant does not interfere with DNA-protein binding, because similar observations were made using DNA-cutting restriction enzymes. We associate the occurrence of denaturation of proteins with the activity of water at the water-protein interface, which was recently proposed in terms of the "water attack model". Our observations suggest that soluble biomolecules can extend an influence over much larger distances than suggested by their actual volume.
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46
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Ngai KL, Capaccioli S, Shinyashiki N. The Protein “Glass” Transition and the Role of the Solvent. J Phys Chem B 2008; 112:3826-32. [DOI: 10.1021/jp710462e] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- K. L. Ngai
- Naval Research Laboratory, Washington, DC, 20375-5320, Dipartimento di Fisica, Università di Pisa, Largo B. Pontecorvo 3, I-56127, Pisa, Italy, and polyLab, CNR-INFM, Largo B. Pontecorvo 3, I-56127, Pisa, Italy, and Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
| | - S. Capaccioli
- Naval Research Laboratory, Washington, DC, 20375-5320, Dipartimento di Fisica, Università di Pisa, Largo B. Pontecorvo 3, I-56127, Pisa, Italy, and polyLab, CNR-INFM, Largo B. Pontecorvo 3, I-56127, Pisa, Italy, and Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
| | - N. Shinyashiki
- Naval Research Laboratory, Washington, DC, 20375-5320, Dipartimento di Fisica, Università di Pisa, Largo B. Pontecorvo 3, I-56127, Pisa, Italy, and polyLab, CNR-INFM, Largo B. Pontecorvo 3, I-56127, Pisa, Italy, and Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
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47
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Narayanan SS, Sinha SS, Sarkar R, Pal SK. Validation and Divergence of the Activation Energy Barrier Crossing Transition at the AOT/Lecithin Reverse Micellar Interface. J Phys Chem B 2008; 112:2859-67. [DOI: 10.1021/jp710127s] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S. Shankara Narayanan
- Unit for Nano Science & Technology, Department of Chemical, Biological & Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India
| | - Sudarson Sekhar Sinha
- Unit for Nano Science & Technology, Department of Chemical, Biological & Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India
| | - Rupa Sarkar
- Unit for Nano Science & Technology, Department of Chemical, Biological & Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India
| | - Samir Kumar Pal
- Unit for Nano Science & Technology, Department of Chemical, Biological & Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India
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48
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Sarangapani PS, Zhu Y. Impeded structural relaxation of a hard-sphere colloidal suspension under confinement. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:010501. [PMID: 18351810 DOI: 10.1103/physreve.77.010501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Revised: 05/31/2007] [Indexed: 05/26/2023]
Abstract
The phenomenon of glass transition, such as the anomalous divergence in viscosity without apparent structural change, remains inadequately understood. We employ spatial confinement to probe length scale dependence on structural relaxation and concomitant glassy dynamics of a hard-sphere poly-(methyl methacrylate) colloidal suspension via confocal microscopy. Remarkable film thickness dependent scaling behavior is observed, where the mobility and relaxation processes of a "fluid" suspension are found to be significantly impeded as film thickness is reduced below 15-20 particle layers.
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Affiliation(s)
- Prasad S Sarangapani
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
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49
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Coupling of protein and hydration-water dynamics in biological membranes. Proc Natl Acad Sci U S A 2007; 104:18049-54. [PMID: 17986611 DOI: 10.1073/pnas.0706566104] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The dynamical coupling between proteins and their hydration water is important for the understanding of macromolecular function in a cellular context. In the case of membrane proteins, the environment is heterogeneous, composed of lipids and hydration water, and the dynamical coupling might be more complex than in the case of the extensively studied soluble proteins. Here, we examine the dynamical coupling between a biological membrane, the purple membrane (PM), and its hydration water by a combination of elastic incoherent neutron scattering, specific deuteration, and molecular dynamics simulations. Examining completely deuterated PM, hydrated in H(2)O, allowed the direct experimental exploration of water dynamics. The study of natural abundance PM in D(2)O focused on membrane dynamics. The temperature-dependence of atomic mean-square displacements shows inflections at 120 K and 260 K for the membrane and at 200 K and 260 K for the hydration water. Because transition temperatures are different for PM and hydration water, we conclude that ps-ns hydration water dynamics are not directly coupled to membrane motions on the same time scale at temperatures <260 K. Molecular-dynamics simulations of hydrated PM in the temperature range from 100 to 296 K revealed an onset of hydration-water translational diffusion at approximately 200 K, but no transition in the PM at the same temperature. Our results suggest that, in contrast to soluble proteins, the dynamics of the membrane protein is not controlled by that of hydration water at temperatures <260 K. Lipid dynamics may have a stronger impact on membrane protein dynamics than hydration water.
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50
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Minimizing frustration by folding in an aqueous environment. Arch Biochem Biophys 2007; 469:118-31. [PMID: 17719000 DOI: 10.1016/j.abb.2007.07.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Accepted: 07/08/2007] [Indexed: 10/23/2022]
Abstract
Although life as we know it evolved in an aqueous medium, the properties of water are not completely understood. In this review, we focus on the role of water in guiding protein folding and stability. Specifically, we discuss the mechanisms of protein folding in an aqueous environment, the effects of water on the folding energy landscape as well as the transition state ensemble, and interactions of water with the folded state. We show that water cannot be viewed as a passive solvent, but rather, plays a very active role in the life of a protein.
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