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Kulkarni P, Bhattacharya S, Achuthan S, Behal A, Jolly MK, Kotnala S, Mohanty A, Rangarajan G, Salgia R, Uversky V. Intrinsically Disordered Proteins: Critical Components of the Wetware. Chem Rev 2022; 122:6614-6633. [PMID: 35170314 PMCID: PMC9250291 DOI: 10.1021/acs.chemrev.1c00848] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Despite the wealth of knowledge gained about intrinsically disordered proteins (IDPs) since their discovery, there are several aspects that remain unexplored and, hence, poorly understood. A living cell is a complex adaptive system that can be described as a wetware─a metaphor used to describe the cell as a computer comprising both hardware and software and attuned to logic gates─capable of "making" decisions. In this focused Review, we discuss how IDPs, as critical components of the wetware, influence cell-fate decisions by wiring protein interaction networks to keep them minimally frustrated. Because IDPs lie between order and chaos, we explore the possibility that they can be modeled as attractors. Further, we discuss how the conformational dynamics of IDPs manifests itself as conformational noise, which can potentially amplify transcriptional noise to stochastically switch cellular phenotypes. Finally, we explore the potential role of IDPs in prebiotic evolution, in forming proteinaceous membrane-less organelles, in the origin of multicellularity, and in protein conformation-based transgenerational inheritance of acquired characteristics. Together, these ideas provide a new conceptual framework to discern how IDPs may perform critical biological functions despite their lack of structure.
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Affiliation(s)
- Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Supriyo Bhattacharya
- Integrative Genomics Core, City of Hope National Medical Center, Duarte, CA, USA
| | - Srisairam Achuthan
- Division of Research Informatics, Center for Informatics, City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Amita Behal
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Mohit Kumar Jolly
- Center for BioSystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Sourabh Kotnala
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Atish Mohanty
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Govindan Rangarajan
- Department of Mathematics, Indian Institute of Science, Bangalore 560012, India
- Center for Neuroscience, Indian Institute of Science, Bangalore 560012, India
| | - Ravi Salgia
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Vladimir Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
- Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy pereulok, 9, Dolgoprudny, Moscow region 141700, Russia
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Activated nanoscale actin-binding domain motion in the catenin-cadherin complex revealed by neutron spin echo spectroscopy. Proc Natl Acad Sci U S A 2021; 118:2025012118. [PMID: 33753508 DOI: 10.1073/pnas.2025012118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
As the core component of the adherens junction in cell-cell adhesion, the cadherin-catenin complex transduces mechanical tension between neighboring cells. Structural studies have shown that the cadherin-catenin complex exists as an ensemble of flexible conformations, with the actin-binding domain (ABD) of α-catenin adopting a variety of configurations. Here, we have determined the nanoscale protein domain dynamics of the cadherin-catenin complex using neutron spin echo spectroscopy (NSE), selective deuteration, and theoretical physics analyses. NSE reveals that, in the cadherin-catenin complex, the motion of the entire ABD becomes activated on nanosecond to submicrosecond timescales. By contrast, in the α-catenin homodimer, only the smaller disordered C-terminal tail of ABD is moving. Molecular dynamics (MD) simulations also show increased mobility of ABD in the cadherin-catenin complex, compared to the α-catenin homodimer. Biased MD simulations further reveal that the applied external forces promote the transition of ABD in the cadherin-catenin complex from an ensemble of diverse conformational states to specific states that resemble the actin-bound structure. The activated motion and an ensemble of flexible configurations of the mechanosensory ABD suggest the formation of an entropic trap in the cadherin-catenin complex, serving as negative allosteric regulation that impedes the complex from binding to actin under zero force. Mechanical tension facilitates the reduction in dynamics and narrows the conformational ensemble of ABD to specific configurations that are well suited to bind F-actin. Our results provide a protein dynamics and entropic explanation for the observed force-sensitive binding behavior of a mechanosensitive protein complex.
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α-Lactalbumin, Amazing Calcium-Binding Protein. Biomolecules 2020; 10:biom10091210. [PMID: 32825311 PMCID: PMC7565966 DOI: 10.3390/biom10091210] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 02/06/2023] Open
Abstract
α-Lactalbumin (α-LA) is a small (Mr 14,200), acidic (pI 4–5), Ca2+-binding protein. α-LA is a regulatory component of lactose synthase enzyme system functioning in the lactating mammary gland. The protein possesses a single strong Ca2+-binding site, which can also bind Mg2+, Mn2+, Na+, K+, and some other metal cations. It contains several distinct Zn2+-binding sites. Physical properties of α-LA strongly depend on the occupation of its metal binding sites by metal ions. In the absence of bound metal ions, α-LA is in the molten globule-like state. The binding of metal ions, and especially of Ca2+, increases stability of α-LA against the action of heat, various denaturing agents and proteases, while the binding of Zn2+ to the Ca2+-loaded protein decreases its stability and causes its aggregation. At pH 2, the protein is in the classical molten globule state. α-LA can associate with membranes at neutral or slightly acidic pH at physiological temperatures. Depending on external conditions, α-LA can form amyloid fibrils, amorphous aggregates, nanoparticles, and nanotubes. Some of these aggregated states of α-LA can be used in practical applications such as drug delivery to tissues and organs. α-LA and some of its fragments possess bactericidal and antiviral activities. Complexes of partially unfolded α-LA with oleic acid are cytotoxic to various tumor and bacterial cells. α-LA in the cytotoxic complexes plays a role of a delivery carrier of cytotoxic fatty acid molecules into tumor and bacterial cells across the cell membrane. Perhaps in the future the complexes of α-LA with oleic acid will be used for development of new anti-cancer drugs.
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Tian B, Garcia Sakai V, Pappas C, van der Goot AJ, Bouwman WG. Fibre formation in calcium caseinate influenced by solvent isotope effect and drying method – A neutron spectroscopy study. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2019.07.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
AbstractThe dynamics of proteins in solution includes a variety of processes, such as backbone and side-chain fluctuations, interdomain motions, as well as global rotational and translational (i.e. center of mass) diffusion. Since protein dynamics is related to protein function and essential transport processes, a detailed mechanistic understanding and monitoring of protein dynamics in solution is highly desirable. The hierarchical character of protein dynamics requires experimental tools addressing a broad range of time- and length scales. We discuss how different techniques contribute to a comprehensive picture of protein dynamics, and focus in particular on results from neutron spectroscopy. We outline the underlying principles and review available instrumentation as well as related analysis frameworks.
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Ameseder F, Radulescu A, Khaneft M, Lohstroh W, Stadler AM. Homogeneous and heterogeneous dynamics in native and denatured bovine serum albumin. Phys Chem Chem Phys 2018; 20:5128-5139. [DOI: 10.1039/c7cp08292d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Quasielastic incoherent neutron spectroscopy experiments reveal that chemical denaturation significantly modifies the internal dynamics of bovine serum albumin.
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Affiliation(s)
- Felix Ameseder
- Jülich Centre for Neutron Science JCNS and Institute for Complex Systems ICS
- Forschungszentrum Jülich GmbH
- 52425 Jülich
- Germany
| | - Aurel Radulescu
- Jülich Centre for Neutron Science JCNS
- Forschungszentrum Jülich GmbH, Outstation at MLZ
- 85747 Garching
- Germany
| | - Marina Khaneft
- Jülich Centre for Neutron Science JCNS
- Forschungszentrum Jülich GmbH, Outstation at MLZ
- 85747 Garching
- Germany
| | - Wiebke Lohstroh
- Heinz Maier-Leibnitz Zentrum
- Technische Universität München
- 85747 Garching
- Germany
| | - Andreas M. Stadler
- Jülich Centre for Neutron Science JCNS and Institute for Complex Systems ICS
- Forschungszentrum Jülich GmbH
- 52425 Jülich
- Germany
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7
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Carpinteri A, Lacidogna G, Piana G, Bassani A. Terahertz mechanical vibrations in lysozyme: Raman spectroscopy vs modal analysis. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.02.099] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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8
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Callaway DJE, Matsui T, Weiss T, Stingaciu LR, Stanley CB, Heller WT, Bu Z. Controllable Activation of Nanoscale Dynamics in a Disordered Protein Alters Binding Kinetics. J Mol Biol 2017; 429:987-998. [PMID: 28285124 DOI: 10.1016/j.jmb.2017.03.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 02/04/2017] [Accepted: 03/02/2017] [Indexed: 01/03/2023]
Abstract
The phosphorylation of specific residues in a flexible disordered activation loop yields precise control of signal transduction. One paradigm is the phosphorylation of S339/S340 in the intrinsically disordered tail of the multi-domain scaffolding protein NHERF1, which affects the intracellular localization and trafficking of NHERF1 assembled signaling complexes. Using neutron spin echo spectroscopy (NSE), we show salt-concentration-dependent excitation of nanoscale motion at the tip of the C-terminal tail in the phosphomimic S339D/S340D mutant. The "tip of the whip" that is unleashed is near the S339/S340 phosphorylation site and flanks the hydrophobic Ezrin-binding motif. The kinetic association rate constant of the binding of the S339D/S340D mutant to the FERM domain of Ezrin is sensitive to buffer salt concentration, correlating with the excited nanoscale dynamics. The results suggest that electrostatics modulates the activation of nanoscale dynamics of an intrinsically disordered protein, controlling the binding kinetics of signaling partners. NSE can pinpoint the nanoscale dynamics changes in a highly specific manner.
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Affiliation(s)
- David J E Callaway
- Department of Chemistry and Biochemistry, City College of New York, CUNY, New York, NY 10031, USA.
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Light Source, Menlo Park, CA 94025, USA
| | - Thomas Weiss
- Stanford Synchrotron Radiation Light Source, Menlo Park, CA 94025, USA
| | - Laura R Stingaciu
- Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at SNS, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Christopher B Stanley
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - William T Heller
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Zimei Bu
- Department of Chemistry and Biochemistry, City College of New York, CUNY, New York, NY 10031, USA.
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9
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Callaway DJ, Bu Z. Visualizing the nanoscale: protein internal dynamics and neutron spin echo spectroscopy. Curr Opin Struct Biol 2016; 42:1-5. [PMID: 27756047 DOI: 10.1016/j.sbi.2016.10.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/01/2016] [Accepted: 10/03/2016] [Indexed: 10/20/2022]
Abstract
The most complex molecular machines are proteins found within cells. Protein dynamics, in particular dynamics on nanoscales, presents us with a novel paradigm for cell signaling: the idea that proteins and protein complexes can communicate directly within themselves to effect long-range information transfer, via coupled domains and correlated residue clusters. This idea has been little explored, in large part because of a paucity of experimental techniques that can address the necessary questions. Here we review recent progress in developing a promising new approach, neutron spin echo spectroscopy.
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Affiliation(s)
- David Je Callaway
- Department of Chemistry and Biochemistry, City College of New York, PhD Programs in Chemistry and Biochemistry, CUNY, United States
| | - Zimei Bu
- Department of Chemistry and Biochemistry, City College of New York, PhD Programs in Chemistry and Biochemistry, CUNY, United States.
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Grimaldo M, Roosen-Runge F, Hennig M, Zanini F, Zhang F, Jalarvo N, Zamponi M, Schreiber F, Seydel T. Hierarchical molecular dynamics of bovine serum albumin in concentrated aqueous solution below and above thermal denaturation. Phys Chem Chem Phys 2016; 17:4645-55. [PMID: 25587698 DOI: 10.1039/c4cp04944f] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dynamics of proteins in solution is a complex and hierarchical process, affected by the aqueous environment as well as temperature. We present a comprehensive study on nanosecond time and nanometer length scales below, at, and above the denaturation temperature Td. Our experimental data evidence dynamical processes in protein solutions on three distinct time scales. We suggest a consistent physical picture of hierarchical protein dynamics: (i) self-diffusion of the entire protein molecule is confirmed to agree with colloid theory for all temperatures where the protein is in its native conformational state. At higher temperatures T > Td, the self-diffusion is strongly obstructed by cross-linking or entanglement. (ii) The amplitude of backbone fluctuations grows with increasing T, and a transition in its dynamics is observed above Td. (iii) The number of mobile side-chains increases sharply at Td while their average dynamics exhibits only little variations. The combination of quasi-elastic neutron scattering and the presented analytical framework provides a detailed microscopic picture of the protein molecular dynamics in solution, thereby reflecting the changes of macroscopic properties such as cluster formation and gelation.
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Affiliation(s)
- Marco Grimaldo
- Institut Max von Laue - Paul Langevin (ILL), CS 20156, F-38042 Grenoble, France.
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11
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Fujiwara S, Araki K, Matsuo T, Yagi H, Yamada T, Shibata K, Mochizuki H. Dynamical Behavior of Human α-Synuclein Studied by Quasielastic Neutron Scattering. PLoS One 2016; 11:e0151447. [PMID: 27097022 PMCID: PMC4838215 DOI: 10.1371/journal.pone.0151447] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 02/29/2016] [Indexed: 12/02/2022] Open
Abstract
α-synuclein (αSyn) is a protein consisting of 140 amino acid residues and is abundant in the presynaptic nerve terminals in the brain. Although its precise function is unknown, the filamentous aggregates (amyloid fibrils) of αSyn have been shown to be involved in the pathogenesis of Parkinson's disease, which is a progressive neurodegenerative disorder. To understand the pathogenesis mechanism of this disease, the mechanism of the amyloid fibril formation of αSyn must be elucidated. Purified αSyn from bacterial expression is monomeric but intrinsically disordered in solution and forms amyloid fibrils under various conditions. As a first step toward elucidating the mechanism of the fibril formation of αSyn, we investigated dynamical behavior of the purified αSyn in the monomeric state and the fibril state using quasielastic neutron scattering (QENS). We prepared the solution sample of 9.5 mg/ml purified αSyn, and that of 46 mg/ml αSyn in the fibril state, both at pD 7.4 in D2O. The QENS experiments on these samples were performed using the near-backscattering spectrometer, BL02 (DNA), at the Materials and Life Science Facility at the Japan Accelerator Research Complex, Japan. Analysis of the QENS spectra obtained shows that diffusive global motions are observed in the monomeric state but largely suppressed in the fibril state. However, the amplitude of the side chain motion is shown to be larger in the fibril state than in the monomeric state. This implies that significant solvent space exists within the fibrils, which is attributed to the αSyn molecules within the fibrils having a distribution of conformations. The larger amplitude of the side chain motion in the fibril state than in the monomeric state implies that the fibril state is entropically favorable.
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Affiliation(s)
- Satoru Fujiwara
- Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai, Ibaraki, Japan
- * E-mail:
| | - Katsuya Araki
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Tatsuhito Matsuo
- Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai, Ibaraki, Japan
| | - Hisashi Yagi
- Center for Research on Green Sustainable Chemistry, Tottori University, Tottori, Japan
| | - Takeshi Yamada
- Research Center for Neutron Science and Technology, CROSS-Tokai, Tokai, Ibaraki, Japan
| | - Kaoru Shibata
- Neutron Science Section, J-PARC Center, Tokai, Ibaraki, Japan
| | - Hideki Mochizuki
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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12
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Roh JH, Tyagi M, Aich P, Kim K, Briber RM, Woodson SA. Charge screening in RNA: an integral route for dynamical enhancements. SOFT MATTER 2015; 11:8741-8745. [PMID: 26430908 DOI: 10.1039/c5sm02084k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Electrostatic interactions of RNA are at the center of determining the dynamical flexibility and structural stability. By analysing neutron scattering spectroscopy, we show that fast dynamics of hydrated tRNA on ps to ns timescales increases with stronger charge screening, while its structural stability either increases or remains largely unchanged. An unprecedented electrostatic threshold for the onset of additional flexibility is induced from the correlation between the charge-screening density of counterions and the promoted dynamical properties. The results demonstrate that the enhanced dynamical flexibility of tRNA originates from local conformational relaxation coupled with stabilized charge screening rather than governed by fluctuation of hydrated counterions. The present study casts light on the specificity of electrostatic interactions in the thermodynamic balance between the dynamical flexibility and structural stability of RNA.
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Affiliation(s)
- Joon Ho Roh
- Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang 37673, South Korea. and Biomolecular Science, University of Science and Technology, Daejeon 34113, South Korea
| | - Madhu Tyagi
- NIST Center for Neutron Research, National Institute of Standards and Techonology, Gaithersburg, Maryland 20899, USA and Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - Pulakesh Aich
- Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang 37673, South Korea.
| | - Kimoon Kim
- Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang 37673, South Korea. and Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, South Korea
| | - R M Briber
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - Sarah A Woodson
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, USA
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13
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Callaway DJE, Farago B, Bu Z. Nanoscale protein dynamics: a new frontier for neutron spin echo spectroscopy. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2013; 36:76. [PMID: 23884624 DOI: 10.1140/epje/i2013-13076-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 12/16/2012] [Accepted: 01/02/2013] [Indexed: 06/02/2023]
Abstract
Recent studies show that neutron spin echo spectroscopy (NSE) can reveal long-range protein domain motions on nanometer lengthscales and on nanosecond to microsecond timescales. This unique capability of NSE provides new opportunities to understand protein dynamics and functions, such as how binding signals are propagated in a protein to distal sites. Here we review our applications of NSE to the study of nanoscale protein domain motions in a set of cell signaling proteins. We summarize the theoretical framework we have developed, which allows one to interpret the NSE data (Biophys. J. 99, 3473 (2010) and Proc. Natl. Acad. Sci. USA 102, 17646 (2005)). Our theoretical framework uses simple concepts from nonequilibrium statistical mechanics, and does not require elaborate molecular dynamics simulations, complex fits to rotational motion, or elastic network models. It is thus more robust than multiparameter techniques that require untestable assumptions. We also demonstrate our experimental scheme involving deuterium labeling of a protein domain or a subunit in a protein complex. We show that our selective deuteration scheme can highlight and resolve specific domain dynamics from the abundant global translational and rotational motions in a protein. Our approach thus clears significant hurdles to the application of NSE for the study of protein dynamics in solution.
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Affiliation(s)
- David J E Callaway
- Department of Chemistry, the City College of New York, New York, NY 10031, USA.
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14
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Duan LL, Gao Y, Mei Y, Zhang QG, Tang B, Zhang JZH. Folding of a helix is critically stabilized by polarization of backbone hydrogen bonds: study in explicit water. J Phys Chem B 2012; 116:3430-5. [PMID: 22369598 DOI: 10.1021/jp212516g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Multiple single-trajectory molecular dynamics (MD) simulation at room temperature (300 K) in explicit water was carried out to study the folding dynamics of an α-helix (PDB 2I9M ) using a polarized charge scheme that includes electronic polarization of backbone hydrogen bonds. Starting from an extended conformation, the 17-residue peptide was successfully folded into the native structure (α-helix) between 80 and 130 ns with a root-mean-square deviation of ~1.0 Å. Analysis of the time-dependent trajectories revealed that helix formation of the peptide started at the terminals and progressed toward the center of the peptide. For comparison, MD trajectories generated under various versions of standard AMBER force fields failed to show any significant or stable helix formation in our simulation. Our result shows clear evidence that the electronic polarization of backbone hydrogen bonds energetically stabilizes the helix formation and is critical to the stable folding of the short helix structure.
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Affiliation(s)
- Li L Duan
- State Key Laboratory of Precision Spectroscopy, Department of Physics, and Institute of Theoretical and Computational Science, East China Normal University, Shanghai 200062, China
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15
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Yoshida K, Vogtt K, Izaola Z, Russina M, Yamaguchi T, Bellissent-Funel MC. Alcohol induced structural and dynamic changes in β-lactoglobulin in aqueous solution: A neutron scattering study. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:502-10. [DOI: 10.1016/j.bbapap.2011.12.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 12/24/2011] [Accepted: 12/29/2011] [Indexed: 11/25/2022]
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16
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Dee DR, Myers B, Yada RY. Dynamics of thermodynamically stable, kinetically trapped, and inhibitor-bound states of pepsin. Biophys J 2012; 101:1699-709. [PMID: 21961596 DOI: 10.1016/j.bpj.2011.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 07/19/2011] [Accepted: 08/01/2011] [Indexed: 11/17/2022] Open
Abstract
The pepsin folding mechanism involves a prosegment (PS) domain that catalyzes folding, which is then removed, resulting in a kinetically trapped native state. Although native pepsin (Np) is kinetically stable, it is irreversibly denatured due to a large folding barrier, and in the absence of the PS it folds to a more thermodynamically stable denatured state, termed refolded pepsin (Rp). This system serves as a model to understand the nature of kinetic barriers and folding transitions between compact states. Quasielastic neutron scattering (QENS) was used to characterize and compare the flexibility of Np, as a kinetically trapped state, with that of Rp, as a thermodynamically stable fold. Additionally, the dynamics of Np were compared with those of a partially unfolded form and a thermally stabilized, inhibitor-bound form. QENS revealed length-scale-dependent differences between Np and Rp on a picosecond timescale and indicated greater flexibility in Np, leading to the conclusion that kinetic stabilization likely does not correspond to reduced internal dynamics. Furthermore, large differences were observed upon inhibition, indicating that QENS of proteins in solution may prove useful for examining the role of conformational entropy changes in ligand binding.
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Affiliation(s)
- Derek R Dee
- Biophysics Interdepartmental Group, University of Guelph, Ontario, Canada
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17
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Roh JH, Tyagi M, Briber RM, Woodson SA, Sokolov AP. The Dynamics of Unfolded versus Folded tRNA: The Role of Electrostatic Interactions. J Am Chem Soc 2011; 133:16406-9. [DOI: 10.1021/ja207667u] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Joon Ho Roh
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland, United States
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, United States
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
| | - Madhu Tyagi
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland, United States
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
| | - R. M. Briber
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland, United States
| | - Sarah A. Woodson
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, United States
| | - Alexei P. Sokolov
- Chemical Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, United States
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18
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Farago B, Li J, Cornilescu G, Callaway DJE, Bu Z. Activation of nanoscale allosteric protein domain motion revealed by neutron spin echo spectroscopy. Biophys J 2011; 99:3473-82. [PMID: 21081097 DOI: 10.1016/j.bpj.2010.09.058] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 09/09/2010] [Accepted: 09/30/2010] [Indexed: 11/15/2022] Open
Abstract
NHERF1 is a multidomain scaffolding protein that assembles signaling complexes, and regulates the cell surface expression and endocytic recycling of a variety of membrane proteins. The ability of the two PDZ domains in NHERF1 to assemble protein complexes is allosterically modulated by the membrane-cytoskeleton linker protein ezrin, whose binding site is located as far as 110 Ångstroms away from the PDZ domains. Here, using neutron spin echo (NSE) spectroscopy, selective deuterium labeling, and theoretical analyses, we reveal the activation of interdomain motion in NHERF1 on nanometer length-scales and on submicrosecond timescales upon forming a complex with ezrin. We show that a much-simplified coarse-grained model suffices to describe interdomain motion of a multidomain protein or protein complex. We expect that future NSE experiments will benefit by exploiting our approach of selective deuteration to resolve the specific domain motions of interest from a plethora of global translational and rotational motions. Our results demonstrate that the dynamic propagation of allosteric signals to distal sites involves changes in long-range coupled domain motions on submicrosecond timescales, and that these coupled motions can be distinguished and characterized by NSE.
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Internal motions of actin characterized by quasielastic neutron scattering. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2011; 40:661-71. [DOI: 10.1007/s00249-011-0669-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 12/28/2010] [Accepted: 01/03/2011] [Indexed: 10/18/2022]
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20
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Proteins move! Protein dynamics and long-range allostery in cell signaling. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2011; 83:163-221. [PMID: 21570668 DOI: 10.1016/b978-0-12-381262-9.00005-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
An emerging point of view in protein chemistry is that proteins are not the static objects that are displayed in textbooks but are instead dynamic actors. Protein dynamics plays a fundamental role in many diseases, and spans a large hierarchy of timescales, from picoseconds to milliseconds or even longer. Nanoscale protein domain motion on length scales comparable to protein dimensions is key to understanding how signals are relayed through multiple protein-protein interactions. A canonical example is how the scaffolding proteins NHERF1 and ezrin work in coordination to assemble crucial membrane complexes. As membrane-cytoskeleton scaffolding proteins, these provide excellent prototypes for understanding how regulatory signals are relayed through protein-protein interactions between the membrane and the cytoskeleton. Here, we review recent progress in understanding the structure and dynamics of the interaction. We describe recent novel applications of neutron spin echo spectroscopy to reveal the dynamic propagation of allosteric signals by nanoscale protein motion, and present a guide to the future study of dynamics and its application to the cure of disease.
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Nakagawa H, Kamikubo H, Kataoka M. Effect of conformational states on protein dynamical transition. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1804:27-33. [DOI: 10.1016/j.bbapap.2009.06.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 06/10/2009] [Accepted: 06/29/2009] [Indexed: 10/20/2022]
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22
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Li J, Callaway DJ, Bu Z. Ezrin induces long-range interdomain allostery in the scaffolding protein NHERF1. J Mol Biol 2009; 392:166-80. [PMID: 19591839 PMCID: PMC2756645 DOI: 10.1016/j.jmb.2009.07.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 07/01/2009] [Accepted: 07/02/2009] [Indexed: 11/17/2022]
Abstract
Scaffolding proteins are molecular switches that control diverse signaling events. The scaffolding protein Na(+)/H(+) exchanger regulatory factor 1 (NHERF1) assembles macromolecular signaling complexes and regulates the macromolecular assembly, localization, and intracellular trafficking of a number of membrane ion transport proteins, receptors, and adhesion/antiadhesion proteins. NHERF1 begins with two modular protein-protein interaction domains-PDZ1 and PDZ2-and ends with a C-terminal (CT) domain. This CT domain binds to ezrin, which, in turn, interacts with cytosekeletal actin. Remarkably, ezrin binding to NHERF1 increases the binding capabilities of both PDZ domains. Here, we use deuterium labeling and contrast variation neutron-scattering experiments to determine the conformational changes in NHERF1 when it forms a complex with ezrin. Upon binding to ezrin, NHERF1 undergoes significant conformational changes in the region linking PDZ2 and its CT ezrin-binding domain, as well as in the region linking PDZ1 and PDZ2, involving very long range interactions over 120 A. The results provide a structural explanation, at mesoscopic scales, of the allosteric control of NHERF1 by ezrin as it assembles protein complexes. Because of the essential roles of NHERF1 and ezrin in intracellular trafficking in epithelial cells, we hypothesize that this long-range allosteric regulation of NHERF1 by ezrin enables the membrane-cytoskeleton to assemble protein complexes that control cross-talk and regulate the strength and duration of signaling.
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Affiliation(s)
- Jianquan Li
- Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111
| | - David J.E. Callaway
- New York University School of Medicine, 550 First Avenue, New York, NY 10016-6402
| | - Zimei Bu
- Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111
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23
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From powder to solution: hydration dependence of human hemoglobin dynamics correlated to body temperature. Biophys J 2009; 96:5073-81. [PMID: 19527667 DOI: 10.1016/j.bpj.2009.03.043] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 02/25/2009] [Accepted: 03/30/2009] [Indexed: 11/23/2022] Open
Abstract
A transition in hemoglobin (Hb), involving partial unfolding and aggregation, has been shown previously by various biophysical methods. The correlation between the transition temperature and body temperature for Hb from different species, suggested that it might be significant for biological function. To focus on such biologically relevant human Hb dynamics, we studied the protein internal picosecond motions as a response to hydration, by elastic and quasielastic neutron scattering. Rates of fast diffusive motions were found to be significantly enhanced with increasing hydration from fully hydrated powder to concentrated Hb solution. In concentrated protein solution, the data showed that amino acid side chains can explore larger volumes above body temperature than expected from normal temperature dependence. The body temperature transition in protein dynamics was absent in fully hydrated powder, indicating that picosecond protein dynamics responsible for the transition is activated only at a sufficient level of hydration. A collateral result from the study is that fully hydrated protein powder samples do not accurately describe all aspects of protein picosecond dynamics that might be necessary for biological function.
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Jansson H, Kargl F, Fernandez-Alonso F, Swenson J. Dynamics of a protein and its surrounding environment: A quasielastic neutron scattering study of myoglobin in water and glycerol mixtures. J Chem Phys 2009; 130:205101. [DOI: 10.1063/1.3138765] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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25
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Chen Y, Ding F, Nie H, Serohijos AW, Sharma S, Wilcox KC, Yin S, Dokholyan NV. Protein folding: then and now. Arch Biochem Biophys 2008; 469:4-19. [PMID: 17585870 PMCID: PMC2173875 DOI: 10.1016/j.abb.2007.05.014] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Revised: 05/11/2007] [Accepted: 05/21/2007] [Indexed: 01/19/2023]
Abstract
Over the past three decades the protein folding field has undergone monumental changes. Originally a purely academic question, how a protein folds has now become vital in understanding diseases and our abilities to rationally manipulate cellular life by engineering protein folding pathways. We review and contrast past and recent developments in the protein folding field. Specifically, we discuss the progress in our understanding of protein folding thermodynamics and kinetics, the properties of evasive intermediates, and unfolded states. We also discuss how some abnormalities in protein folding lead to protein aggregation and human diseases.
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Affiliation(s)
| | | | | | | | | | | | | | - Nikolay V. Dokholyan
- † To whom correspondence should be addressed: Nikolay V. Dokholyan, Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, North Carolina 27599. Fax: 919-966-2852.
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26
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Bu Z, Biehl R, Monkenbusch M, Richter D, Callaway DJE. Coupled protein domain motion in Taq polymerase revealed by neutron spin-echo spectroscopy. Proc Natl Acad Sci U S A 2005; 102:17646-51. [PMID: 16306270 PMCID: PMC1345721 DOI: 10.1073/pnas.0503388102] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Long-range conformational changes in proteins are ubiquitous in biology for the transmission and amplification of signals; such conformational changes can be triggered by small-amplitude, nanosecond protein domain motion. Understanding how conformational changes are initiated requires the characterization of protein domain motion on these timescales and on length scales comparable to protein dimensions. Using neutron spin-echo spectroscopy (NSE), normal mode analysis, and a statistical-mechanical framework, we reveal overdamped, coupled domain motion within DNA polymerase I from Thermus aquaticus (Taq polymerase). This protein utilizes correlated domain dynamics over 70 angstroms to coordinate nucleotide synthesis and cleavage during DNA synthesis and repair. We show that NSE spectroscopy can determine the domain mobility tensor, which determines the degree of dynamical coupling between domains. The mobility tensor defines the domain velocity response to a force applied to it or to another domain, just as the sails of a sailboat determine its velocity given the applied wind force. The NSE results provide insights into the nature of protein domain motion that are not appreciated by conventional biophysical techniques.
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Affiliation(s)
- Zimei Bu
- Fox Chase Cancer Center, 333 Cottman Avenue, Reimann 414, Philadelphia, PA 19111, USA.
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27
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Gabel F, Weik M, Masson P, Renault F, Fournier D, Brochier L, Doctor BP, Saxena A, Silman I, Zaccai G. Effects of soman inhibition and of structural differences on cholinesterase molecular dynamics: a neutron scattering study. Biophys J 2005; 89:3303-11. [PMID: 16100272 PMCID: PMC1366826 DOI: 10.1529/biophysj.105.061028] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Incoherent elastic neutron scattering experiments on members of the cholinesterase family were carried out to investigate how molecular dynamics is affected by covalent inhibitor binding and by differences in primary and quaternary structure. Tetrameric native and soman-inhibited human butyrylcholinesterase (HuBChE) as well as native dimeric Drosophila melanogaster acetylcholinesterase (DmAChE) hydrated protein powders were examined. Atomic mean-square displacements (MSDs) were found to be identical for native HuBChE and for DmAChE in the whole temperature range examined, leading to the conclusion that differences in activity and substrate specificity are not reflected by a global modification of subnanosecond molecular dynamics. MSDs of native and soman-inhibited HuBChE were identical below the thermal denaturation temperature of the native enzyme, indicating a common mean free-energy surface. Denaturation of the native enzyme is reflected by a relative increase of MSDs consistent with entropic stabilization of the unfolded state. The results suggest that the stabilization of HuBChE phosphorylated by soman is due to an increase in free energy of the unfolded state due to a decrease in entropy.
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Affiliation(s)
- F Gabel
- Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale, 41 rue Jules Horowitz, F-38027 Grenoble Cedex 1, France
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28
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Ding F, Jha RK, Dokholyan NV. Scaling Behavior and Structure of Denatured Proteins. Structure 2005; 13:1047-54. [PMID: 16004876 DOI: 10.1016/j.str.2005.04.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Revised: 03/30/2005] [Accepted: 04/03/2005] [Indexed: 10/25/2022]
Abstract
An ensemble of random-coil conformations with no persistent structures has long been accepted as the classical model of denatured proteins due to its consistency with the experimentally determined scaling of protein sizes. However, recent NMR spectroscopy studies on proteins at high chemical denaturant concentrations suggest the presence of significant amounts of native-like structures, in contrast to the classical random-coil picture. To reconcile these seemingly controversial observations, we examine thermally denatured states of experimentally characterized proteins by using molecular dynamics simulations. For all studied proteins, we find that denatured states indeed have strong local conformational bias toward native states while a random-coil power law scaling of protein sizes is preserved. In addition, we explain why experimentally determined size of the protein creatine kinase does not follow general scaling. In simulations, we observe that this protein exhibits a stable intermediate state, the size of which is consistent with the reported experimental observation.
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Affiliation(s)
- Feng Ding
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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29
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Wei Z, Song J. Molecular mechanism underlying the thermal stability and pH-induced unfolding of CHABII. J Mol Biol 2005; 348:205-18. [PMID: 15808864 DOI: 10.1016/j.jmb.2005.02.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2004] [Revised: 02/14/2005] [Accepted: 02/15/2005] [Indexed: 10/25/2022]
Abstract
The 37-residue alpha/beta protein CHABII was previously demonstrated to undergo a gradual pH-induced unfolding. It has been shown that even at pH 4.0 CHABII still retained a highly native-like secondary structure and tertiary topology although its tight side-chain packing was severely disrupted, typical of the molten globule state. Here, we have expressed and refolded the recombinant proteins of CHABII and its mutant [Phe21]-CHABII, and subsequently conducted extensive CD and NMR characterizations. The results indicated: (1) replacement of His21 by Phe in [Phe21]-CHABII eliminated the pH-induced unfolding from pH 6.5 to 4.0, indicating that His21 was responsible for the observed pH-induced unfolding of CHABII. Further examinations revealed that although the pH-induced unfolding of CHABII was also triggered by the protonation of the His residue as previously uncovered for apomyoglobin, their molecular mechanisms are different. (2) Monitoring the pH-induced unfolding by 1H-15N HSQC spectroscopy allowed us to visualize the gradual development of the CHABII molten globule. At pH 4.0, the HSQC spectrum of CHABII was poorly dispersed with dispersions of approximately 1 ppm over proton dimension and 10 ppm over 15N dimension, characteristic of severely or even "completely unfolded" proteins. One the other hand, unambiguous assignments of the NOESY spectra of CHABII led to the identification of the persistent medium and long-range NOEs at pH 4.0, which define a highly native-like secondary structure and tertiary packing. This implies that the degree of the native-like topology might be underestimated in the previous characterization of partially folded and even completely unfolded proteins. (3) Replacement of His21 by Phe with higher side-chain hydrophobicity only caused a minor structural rearrangement but considerably enhanced the packing interaction of the hydrophobic core, as evident from a dramatic increase in NOE contacts in [Phe21]-CHABII. The enhancement led to an increase of the thermal stability of [Phe21]-CHABII by approximately 17 deg. C.
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Affiliation(s)
- Zheng Wei
- Department of Biological Sciences, National University of Singapore, 10 Kent Ridge, Crescent, Singapore 119260
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30
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Tehei M, Franzetti B, Madern D, Ginzburg M, Ginzburg BZ, Giudici-Orticoni MT, Bruschi M, Zaccai G. Adaptation to extreme environments: macromolecular dynamics in bacteria compared in vivo by neutron scattering. EMBO Rep 2004; 5:66-70. [PMID: 14710189 PMCID: PMC1298960 DOI: 10.1038/sj.embor.7400049] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2003] [Revised: 09/29/2003] [Accepted: 10/13/2003] [Indexed: 11/09/2022] Open
Abstract
Mean macromolecular dynamics was quantified in vivo by neutron scattering in psychrophile, mesophile, thermophile and hyperthermophile bacteria. Root mean square atomic fluctuation amplitudes determining macromolecular flexibility were found to be similar for each organism at its physiological temperature ( approximately 1 A in the 0.1 ns timescale). Effective force constants determining the mean macromolecular resilience were found to increase with physiological temperature from 0.2 N/m for the psychrophiles, which grow at 4 degrees C, to 0.6 N/m for the hyperthermophiles (85 degrees C), indicating that the increase in stabilization free energy is dominated by enthalpic rather than entropic terms. Larger resilience allows macromolecular stability at high temperatures, while maintaining flexibility within acceptable limits for biological activity.
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Affiliation(s)
- Moeava Tehei
- Institut de Biologie Structurale, CEA-CNRS-UJF, IBS, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France
| | - Bruno Franzetti
- Institut de Biologie Structurale, CEA-CNRS-UJF, IBS, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France
| | - Dominique Madern
- Institut de Biologie Structurale, CEA-CNRS-UJF, IBS, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France
| | - Margaret Ginzburg
- Institute of Life Sciences, Hebrew University, Jerusalem 24410, Israel
| | - Ben Z Ginzburg
- Institute of Life Sciences, Hebrew University, Jerusalem 24410, Israel
| | | | - Mireille Bruschi
- Bioénergétique et Ingéniene des Protéines, CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Giuseppe Zaccai
- Institut de Biologie Structurale, CEA-CNRS-UJF, IBS, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France
- Institut Laue Langevin, B.P. 156X, 38042 Grenoble Cedex 9, France
- Tel: +33 4 38 78 95 73; Fax: +33 4 38 78 54 94; E-mail:
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31
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Ho DL, Byrnes WM, Ma WP, Shi Y, Callaway DJE, Bu Z. Structure-specific DNA-induced conformational changes in Taq polymerase revealed by small angle neutron scattering. J Biol Chem 2004; 279:39146-54. [PMID: 15247286 DOI: 10.1074/jbc.m404565200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The DNA polymerase I from Thermus aquaticus (Taq polymerase) performs lagging-strand DNA synthesis and DNA repair. Taq polymerase contains a polymerase domain for synthesizing a new DNA strand and a 5'-nuclease domain for cleaving RNA primers or damaged DNA strands. The extended crystal structure of Taq polymerase poses a puzzle on how this enzyme coordinates its polymerase and the nuclease activities to generate only a nick. Using contrast variation solution small angle neutron scattering, we have examined the conformational changes that occur in Taq polymerase upon binding "overlap flap" DNA, a structure-specific DNA substrate that mimics the substrate in strand replacement reactions. In solution, apoTaq polymerase has an overall expanded equilibrium conformation similar to that in the crystal structure. Upon binding to the DNA substrate, both the polymerase and the nuclease domains adopt more compact overall conformations, but these changes are not enough to bring the two active sites close enough to generate a nick. Reconstruction of the three-dimensional molecular envelope from small angle neutron scattering data shows that in the DNA-bound form, the nuclease domain is lifted up relative to its position in the non-DNA-bound form so as to be in closer contact with the thumb and palm subdomains of the polymerase domain. The results suggest that a form of structure sensing is responsible for the coordination of the polymerase and nuclease activities in nick generation. However, interactions between the polymerase and the nuclease domains can assist in the transfer of the DNA substrate from one active site to the other.
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Affiliation(s)
- Derek L Ho
- National Institute of Standards and Technology, Gaithersburg, Maryland 20898, USA
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32
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Ozkan S, Dalgýn GS, Haliloglu T. Unfolding events of Chymotrypsin Inhibitor 2 (CI2) revealed by Monte Carlo (MC) simulations and their consistency from structure-based analysis of conformations. POLYMER 2004. [DOI: 10.1016/j.polymer.2003.10.092] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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33
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Gun'ko VM, Klyueva AV, Levchuk YN, Leboda R. Photon correlation spectroscopy investigations of proteins. Adv Colloid Interface Sci 2003; 105:201-328. [PMID: 12969646 DOI: 10.1016/s0001-8686(03)00091-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Physical principles of photon correlation spectroscopy (PCS), mathematical treatment of the PCS data (converting autocorrelation functions to distribution functions or average characteristics), and PCS applications to study proteins and other biomacromolecules in aqueous media are described and analysed. The PCS investigations of conformational changes in protein molecules, their aggregation itself or in consequence of interaction with other molecules or organic (polymers) and inorganic (e.g. fumed silica) fine particles as well as the influence of low molecular compounds (surfactants, drugs, salts, metal ions, etc.) reveal unique capability of the PCS techniques for elucidation of important native functions of proteins and other biomacromolecules (DNA, RNA, etc.) or microorganisms (Escherichia coli, Pseudomonas putida, Dunaliella viridis, etc.). Special attention is paid to the interaction of proteins with fumed oxides and the impact of polymers and fine oxide particles on the motion of living flagellar microorganisms analysed by means of PCS.
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Affiliation(s)
- Vladimir M Gun'ko
- Institute of Surface Chemistry, 17 General Naumov Street, Kiev 03164, Ukraine.
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34
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Nölting B, Schälike W, Hampel P, Grundig F, Gantert S, Sips N, Bandlow W, Qi PX. Structural determinants of the rate of protein folding. J Theor Biol 2003; 223:299-307. [PMID: 12850450 DOI: 10.1016/s0022-5193(03)00091-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To understand the mechanism of protein folding and to assist rational design of fast-folding, non-aggregating and stable artificial enzymes, it is essential to determine the structural parameters which govern the rate constants of folding, kf. It has been found that -logkf is a linear function of the so-called chain topology parameter (CTP) within the range of 10(-1)s(-1)< or = kf < or =10(8)s(-1). The correlation between -logkf and CTP is much improved than using previously published contact order (CO) method. It has been further suggested that short sequence separations may be preferred for the establishment of stable interactions for the design of novel artificial enzymes and the modification of slow-folding proteins with aggregating intermediates.
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Affiliation(s)
- Bengt Nölting
- Prussian Private Institute of Technology at Berlin, Am Schlosspark 30, Berlin D-13187, Germany.
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35
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Characterization of sub-nanosecond dynamics of the molten globule state of α-lactalbumin using quasielastic neutron scattering and molecular dynamics simulations. Chem Phys 2003. [DOI: 10.1016/s0301-0104(03)00291-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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36
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Russo D, Pérez J, Zanotti JM, Desmadril M, Durand D. Dynamic transition associated with the thermal denaturation of a small Beta protein. Biophys J 2002; 83:2792-800. [PMID: 12414711 PMCID: PMC1302363 DOI: 10.1016/s0006-3495(02)75288-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We studied the temperature dependence of the picosecond internal dynamics of an all-beta protein, neocarzinostatin, by incoherent quasielastic neutron scattering. Measurements were made between 20 degrees C and 71 degrees C in heavy water solution. At 20 degrees C, only 33% of the nonexchanged hydrogen atoms show detectable dynamics, a number very close to the fraction of protons involved in the side chains of random coil structures, therefore suggesting a rigid structure in which the only detectable diffusive movements are those involving the side chains of random coil structures. At 61.8 degrees C, although the protein structure is still native, slight dynamic changes are detected that could reflect enhanced backbone and beta-sheet side-chain motions at this higher temperature. Conversely, all internal dynamics parameters (amplitude of diffusive motions, fraction of immobile scatterers, mean-squared vibration amplitude) rapidly change during heat-induced unfolding, indicating a major loss of rigidity of the beta-sandwich structure. The number of protons with diffusive motion increases markedly, whereas the volume occupied by the diffusive motion of protons is reduced. At the half-transition temperature (T = 71 degrees C) most of backbone and beta-sheet side-chain hydrogen atoms are involved in picosecond dynamics.
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Affiliation(s)
- Daniela Russo
- Laboratoire Léon Brillouin, CE Saclay, 91191 Gif-sur-Yvette Cédex, France
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