1
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Ceccolini I, Kauffmann C, Holzinger J, Konrat R, Zawadzka-Kazimierczuk A. A set of cross-correlated relaxation experiments to probe the correlation time of two different and complementary spin pairs. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 361:107661. [PMID: 38547550 DOI: 10.1016/j.jmr.2024.107661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/12/2024] [Accepted: 03/14/2024] [Indexed: 04/20/2024]
Abstract
Intrinsically disordered proteins (IDPs) defy the conventional structure-function paradigm by lacking a well-defined tertiary structure and exhibiting inherent flexibility. This flexibility leads to distinctive spin relaxation modes, reflecting isolated and specific motions within individual peptide planes. In this work, we propose a new pulse sequence to measure the longitudinal 13C' CSA-13C'-13Cα DD CCR rate [Formula: see text] and present a novel 3D version of the transverse [Formula: see text] CCR rate, adopting the symmetrical reconversion approach. We combined these rates with the analogous ΓxyN/NH and ΓzN/NH CCR rates to derive residue-specific correlation times for both spin-pairs within the same peptide plane. The presented approach offers a straightforward and intuitive way to compare the correlation times of two different and complementary spin vectors, anticipated to be a valuable aid to determine IDPs backbone dihedral angles distributions. We performed the proposed experiments on two systems: a folded protein ubiquitin and Coturnix japonica osteopontin, a prototypical IDP. Comparative analyses of the results show that the correlation times of different residues vary more for IDPs than globular proteins, indicating that the dynamics of IDPs is largely heterogeneous and dominated by local fluctuations.
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Affiliation(s)
- Irene Ceccolini
- Department of Structural and Computational Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter Campus 5, 1030 Vienna, Austria
| | | | - Julian Holzinger
- Department of Structural and Computational Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter Campus 5, 1030 Vienna, Austria
| | - Robert Konrat
- Department of Structural and Computational Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter Campus 5, 1030 Vienna, Austria.
| | - Anna Zawadzka-Kazimierczuk
- University of Warsaw, Faculty of Chemistry, Biological and Chemical Research Centre, Żwirki i Wigury 101, 02-089 Warsaw, Poland.
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2
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Abyzov A, Mandelkow E, Zweckstetter M, Rezaei-Ghaleh N. Fast Motions Dominate Dynamics of Intrinsically Disordered Tau Protein at High Temperatures. Chemistry 2023; 29:e202203493. [PMID: 36579699 DOI: 10.1002/chem.202203493] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/17/2022] [Accepted: 12/21/2022] [Indexed: 12/30/2022]
Abstract
Reorientational dynamics of intrinsically disordered proteins (IDPs) contain multiple motions often clustered around three motional modes: ultrafast librational motions of amide groups, fast local backbone conformational fluctuations and slow chain segmental motions. This dynamic picture is mainly based on 15 N NMR relaxation studies of IDPs at relatively low temperatures where the amide-water proton exchange rates are sufficiently small. Less is known, however, about the dynamics of IDPs at more physiological temperatures. Here, we investigate protein dynamics in a 441-residue long IDP, tau protein, in the temperature range from 0-25 °C, using 15 N NMR relaxation rates and spectral density analysis. While at these temperatures relaxation rates are still better described in terms of amide group librational motions, local backbone dynamics and chain segmental motions, the temperature-dependent trend of spectral densities suggests that the timescales of fast backbone conformational fluctuations and slower chain segmental motions might become inseparable at higher temperatures. Our data demonstrate the remarkable dynamic plasticity of this prototypical IDP and highlight the need for dynamic studies of IDPs at multiple temperatures.
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Affiliation(s)
- Anton Abyzov
- Translational Structural Biology Group, German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, D-37075, Göttingen, Germany
| | - Eckhard Mandelkow
- German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, D-53127, Bonn, Germany
- Research Center CAESAR, Ludwig-Erhard-Allee 2, D-53175, Bonn, Germany
| | - Markus Zweckstetter
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077, Göttingen, Germany
- Translational Structural Biology Group, German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, D-37075, Göttingen, Germany
| | - Nasrollah Rezaei-Ghaleh
- Institute of Physical Biology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, D-40225, Düsseldorf, Germany
- Institute of Biological Information Processing, IBI-7: Structural Biochemistry, Forschungszentrum Jülich, D-52428, Jülich, Germany
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077, Göttingen, Germany
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3
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How does it really move? Recent progress in the investigation of protein nanosecond dynamics by NMR and simulation. Curr Opin Struct Biol 2022; 77:102459. [PMID: 36148743 DOI: 10.1016/j.sbi.2022.102459] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 07/29/2022] [Accepted: 08/05/2022] [Indexed: 12/14/2022]
Abstract
Nuclear magnetic resonance (NMR) spin relaxation experiments currently probe molecular motions on timescales from picoseconds to nanoseconds. The detailed interpretation of these motions in atomic detail benefits from complementarity with the results from molecular dynamics (MD) simulations. In this mini-review, we describe the recent developments in experimental techniques to study the backbone dynamics from 15N relaxation and side-chain dynamics from 13C relaxation, discuss the different analysis approaches from model-free to dynamics detectors, and highlight the many ways that NMR relaxation experiments and MD simulations can be used together to improve the interpretation and gain insights into protein dynamics.
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4
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Salvi N, Zapletal V, Jaseňáková Z, Zachrdla M, Padrta P, Narasimhan S, Marquardsen T, Tyburn JM, Žídek L, Blackledge M, Ferrage F, Kadeřávek P. Convergent views on disordered protein dynamics from NMR and computational approaches. Biophys J 2022; 121:3785-3794. [PMID: 36131545 PMCID: PMC9674986 DOI: 10.1016/j.bpj.2022.09.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 09/07/2022] [Accepted: 09/15/2022] [Indexed: 11/02/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) or intrinsically disordered regions (IDRs) is a class of biologically important proteins exhibiting specific biophysical characteristics. They lack a hydrophobic core, and their conformational behavior is strongly influenced by electrostatic interactions. IDPs and IDRs are highly dynamic, and a characterization of the motions of IDPs and IDRs is essential for their physically correct description. NMR together with molecular dynamics simulations are the methods best suited to such a task because they provide information about dynamics of proteins with atomistic resolution. Here, we present a study of motions of a disordered C-terminal domain of the delta subunit of RNA polymerase from Bacillus subtilis. Positively and negatively charged residues in the studied domain form transient electrostatic contacts critical for the biological function. Our study is focused on investigation of ps-ns dynamics of backbone of the delta subunit based on analysis of amide 15N NMR relaxation data and molecular dynamics simulations. In order to extend an informational content of NMR data to lower frequencies, which are more sensitive to slower motions, we combined standard (high-field) NMR relaxation experiments with high-resolution relaxometry. Altogether, we collected data reporting the relaxation at 12 different magnetic fields, resulting in an unprecedented data set. Our results document that the analysis of such data provides a consistent description of dynamics and confirms the validity of so far used protocols of the analysis of dynamics of IDPs also for a partially folded protein. In addition, the potential to access detailed description of motions at the timescale of tens of ns with the help of relaxometry data is discussed. Interestingly, in our case, it appears to be mostly relevant for a region involved in the formation of temporary contacts within the disordered region, which was previously proven to be biologically important.
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Affiliation(s)
- Nicola Salvi
- Institut de Biologie Structurale (IBS), CEA, CNRS, University Grenoble Alpes, Grenoble, France
| | - Vojtěch Zapletal
- National Centre for Biomolecular Research, Faculty of Science and Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Zuzana Jaseňáková
- National Centre for Biomolecular Research, Faculty of Science and Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Milan Zachrdla
- Laboratoire des Biomolécules, LBM, Département de chimie, École normale supérieure, PSL University, Sorbonne Université, CNRS, Paris, France
| | - Petr Padrta
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Subhash Narasimhan
- National Centre for Biomolecular Research, Faculty of Science and Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | | | | | - Lukáš Žídek
- National Centre for Biomolecular Research, Faculty of Science and Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Martin Blackledge
- Institut de Biologie Structurale (IBS), CEA, CNRS, University Grenoble Alpes, Grenoble, France.
| | - Fabien Ferrage
- Laboratoire des Biomolécules, LBM, Département de chimie, École normale supérieure, PSL University, Sorbonne Université, CNRS, Paris, France.
| | - Pavel Kadeřávek
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic.
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5
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Bolik-Coulon N, Ferrage F. Explicit models of motions to analyze NMR relaxation data in proteins. J Chem Phys 2022; 157:125102. [DOI: 10.1063/5.0095910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Nuclear Magnetic Resonance (NMR) is a tool of choice to characterize molecular motions. In biological macromolecules, pico- to nano-second motions, in particular, can be probed by nuclear spin relaxation rates which depend on the time fluctuations of the orientations of spin interaction frames. For the past 40 years, relaxation rates have been successfully analyzed using the Model Free (MF) approach which makes no assumption on the nature of motions and reports on the effective amplitude and time-scale of the motions. However, obtaining a mechanistic picture of motions from this type of analysis is difficult at best, unless complemented with molecular dynamics (MD) simulations. In spite of their limited accuracy, such simulations can be used to obtain the information necessary to build explicit models of motions designed to analyze NMR relaxation data. Here, we present how to build such models, suited in particular to describe motions of methyl-bearing protein side-chains and compare them with the MF approach. We show on synthetic data that explicit models of motions are more robust in the presence of rotamer jumps which dominate the relaxation in methyl groups of protein side-chains. We expect this work to motivate the use of explicit models of motion to analyze MD and NMR data.
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Affiliation(s)
| | - Fabien Ferrage
- Departement de chimie, Ecole Normale Superieure Departement de Chimie, France
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6
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Anderson JS, Hernández G, LeMaster DM. Molecular Dynamics-Assisted Optimization of Protein NMR Relaxation Analysis. J Chem Theory Comput 2022; 18:2091-2104. [PMID: 35245056 PMCID: PMC9009080 DOI: 10.1021/acs.jctc.1c01165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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NMR relaxation analysis
of the mobile residues in globular proteins
is sensitive to the form of the experimentally fitted internal autocorrelation
function, which is used to represent that motion. Different order
parameter representations can precisely fit the same set of 15N R1, R2,
and heteronuclear NOE measurements while yielding significantly divergent
predictions of the underlying autocorrelation functions, indicating
the insufficiency of these experimental relaxation data for assessing
which order parameter representation provides the most physically
realistic predictions. Molecular dynamics simulations offer an unparalleled
capability for discriminating among different order parameter representations
to assess which representation can most accurately model a wide range
of physically realistic autocorrelation functions. Six currently utilized
AMBER and CHARMM force fields were applied to calculate autocorrelation
functions for the backbone H–N bond vectors of ubiquitin as
an operational test set. An optimized time constant-constrained triexponential
(TCCT) representation was shown to markedly outperform the widely
used (Sf2,τs,S2) extended
Lipari–Szabo representation and the more closely related (Sf2,SH2, SN2) Larmor frequency-selective representation.
Optimization of the TCCT representation at both 600 and 900 MHz 1H converged to the same parameterization. The higher magnetic
field yielded systematically larger deviations in the back-prediction
of the autocorrelation functions for the mobile amides, indicating
little added benefit from multiple field measurements in analyzing
amides that lack slower (∼ms) exchange line-broadening effects.
Experimental 15N relaxation data efficiently distinguished
among the different force fields with regard to their prediction of
ubiquitin backbone conformational dynamics in the ps–ns time
frame. While the earlier AMBER 99SB and CHARMM27 force fields underestimate
the scale of backbone dynamics, which occur in this time frame, AMBER
14SB provided the most consistent predictions for the well-averaged
highly mobile C-terminal residues of ubiquitin.
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Affiliation(s)
- Janet S Anderson
- Department of Chemistry, Union College, Schenectady, New York 12308, United States
| | - Griselda Hernández
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, New York 12201, United States
| | - David M LeMaster
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, New York 12201, United States
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7
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Kauffmann C, Ceccolini I, Kontaxis G, Konrat R. Detecting anisotropic segmental dynamics in disordered proteins by cross-correlated spin relaxation. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:557-569. [PMID: 37905226 PMCID: PMC10539831 DOI: 10.5194/mr-2-557-2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 06/02/2021] [Indexed: 11/01/2023]
Abstract
Among the numerous contributions of Geoffrey Bodenhausen to NMR spectroscopy, his developments in the field of spin-relaxation methodology and theory will definitely have a long lasting impact. Starting with his seminal contributions to the excitation of multiple-quantum coherences, he and his group thoroughly investigated the intricate relaxation properties of these "forbidden fruits" and developed experimental techniques to reveal the relevance of previously largely ignored cross-correlated relaxation (CCR) effects, as "the essential is invisible to the eyes". Here we consider CCR within the challenging context of intrinsically disordered proteins (IDPs) and emphasize its potential and relevance for the studies of structural dynamics of IDPs in the future years to come. Conventionally, dynamics of globularly folded proteins are modeled and understood as deviations from otherwise rigid structures tumbling in solution. However, with increasing protein flexibility, as observed for IDPs, this apparent dichotomy between structure and dynamics becomes blurred. Although complex dynamics and ensemble averaging might impair the extraction of mechanistic details even further, spin relaxation uniquely encodes a protein's structural memory. Due to significant methodological developments, such as high-dimensional non-uniform sampling techniques, spin relaxation in IDPs can now be monitored in unprecedented resolution. Not embedded within a rigid globular fold, conventional 15 N spin probes might not suffice to capture the inherently local nature of IDP dynamics. To better describe and understand possible segmental motions of IDPs, we propose an experimental approach to detect the signature of anisotropic segmental dynamics by quantifying cross-correlated spin relaxation of individual 15 N 1 H N and 13 C ' 13 C α spin pairs. By adapting Geoffrey Bodenhausen's symmetrical reconversion principle to obtain zero frequency spectral density values, we can define and demonstrate more sensitive means to characterize anisotropic dynamics in IDPs.
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Affiliation(s)
- Clemens Kauffmann
- Department of Structural and Computational Biology, Max Perutz Laboratories, University of Vienna, Campus-Vienna-Biocenter 5, 1030 Vienna, Austria
| | - Irene Ceccolini
- Department of Structural and Computational Biology, Max Perutz Laboratories, University of Vienna, Campus-Vienna-Biocenter 5, 1030 Vienna, Austria
| | - Georg Kontaxis
- Department of Structural and Computational Biology, Max Perutz Laboratories, University of Vienna, Campus-Vienna-Biocenter 5, 1030 Vienna, Austria
| | - Robert Konrat
- Department of Structural and Computational Biology, Max Perutz Laboratories, University of Vienna, Campus-Vienna-Biocenter 5, 1030 Vienna, Austria
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8
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Crawley T, Palmer AG. Bootstrap Aggregation for Model Selection in the Model-free Formalism. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:251-264. [PMID: 34414396 PMCID: PMC8372780 DOI: 10.5194/mr-2-251-2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The ability to make robust inferences about the dynamics of biological macromolecules using NMR spectroscopy depends heavily on the application of appropriate theoretical models for nuclear spin relaxation. Data analysis for NMR laboratory-frame relaxation experiments typically involves selecting one of several model-free spectral density functions using a bias-corrected fitness test. Here, advances in statistical model selection theory, termed bootstrap aggregation or bagging, are applied to 15N spin relaxation data, developing a multimodel inference solution to the model-free selection problem. The approach is illustrated using data sets recorded at four static magnetic fields for the bZip domain of the S. cerevisiae transcription factor GCN4.
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Affiliation(s)
- Timothy Crawley
- Department of Biochemistry and Molecular Biophysics, Columbia University, 630 West 168th Street, New York, NY 10032, United States
| | - Arthur G. Palmer
- Department of Biochemistry and Molecular Biophysics, Columbia University, 630 West 168th Street, New York, NY 10032, United States
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9
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Anderson JS, Hernández G, LeMaster DM. 13C NMR Relaxation Analysis of Protein GB3 for the Assessment of Side Chain Dynamics Predictions by Current AMBER and CHARMM Force Fields. J Chem Theory Comput 2020; 16:2896-2913. [PMID: 32268062 DOI: 10.1021/acs.jctc.0c00050] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Molecular simulations with seven current AMBER- and CHARMM-based force fields yield markedly differing internal bond vector autocorrelation function predictions for many of the 223 methine and methylene H-C bonds of the 56-residue protein GB3. To enable quantification of accuracy, 13C R1, R2, and heteronuclear NOE relaxation rates have been determined for the methine and stereochemically assigned methylene Cα and Cβ positions. With only three experimental relaxation values for each bond vector, central to this analysis is the accuracy with which MD-derived autocorrelation curves can be represented by a 3-parameter equation which, in turn, maps onto the NMR relaxation values. In contrast to the more widely used extended Lipari-Szabo order parameter representation, 95% of these MD-derived internal autocorrelation curves for GB3 can be fitted to within 1.0% rmsd over the time frame from 30 ps to 4 ns by a biexponential Larmor frequency-selective representation (LF-S2). Applying the LF-S2 representation to the experimental relaxation rates and uncertainties serves to determine the boundary range for the autocorrelation function of each bond vector consistent with the experimental data. Not surprisingly, all seven force fields predict the autocorrelation functions for the more motionally restricted 1Hα-13Cα and 1Hβ-13Cβ bond vectors with reasonable accuracy. However, for the 1Hβ-13Cβ bond vectors exhibiting aggregate order parameter S2 values less than 0.85, only 1% of the MD-derived predictions lie with 1 σ of the experimentally determined autocorrelation functions and only 7% within 2 σ. On the other hand, substantial residue type-specific improvements in predictive performance were observed among the recent AMBER force fields. This analysis indicates considerable potential for the use of 13C relaxation measurements in guiding the optimization of the side chain dynamics characteristics of protein molecular simulations.
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Affiliation(s)
- Janet S Anderson
- Department of Chemistry, Union College, Schenectady, New York 12308, United States
| | - Griselda Hernández
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, New York 12201, United States
| | - David M LeMaster
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, New York 12201, United States
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10
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Bolik-Coulon N, Kadeřávek P, Pelupessy P, Dumez JN, Ferrage F, Cousin SF. Theoretical and computational framework for the analysis of the relaxation properties of arbitrary spin systems. Application to high-resolution relaxometry. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 313:106718. [PMID: 32234674 DOI: 10.1016/j.jmr.2020.106718] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/11/2020] [Accepted: 03/13/2020] [Indexed: 06/11/2023]
Abstract
A wide variety of nuclear magnetic resonance experiments rely on the prediction and analysis of relaxation processes. Recently, innovative approaches have been introduced where the sample travels through a broad range of magnetic fields in the course of the experiment, such as dissolution dynamic nuclear polarization or high-resolution relaxometry. Understanding the relaxation properties of nuclear spin systems over orders of magnitude of magnetic fields is essential to rationalize the results of these experiments. For example, during a high-resolution relaxometry experiment, the absence of control of nuclear spin relaxation pathways during the sample transfers and relaxation delays leads to systematic deviations of polarization decays from an ideal mono-exponential decay with the pure longitudinal relaxation rate. These deviations have to be taken into account to describe quantitatively the dynamics of the system. Here, we present computational tools to (1) calculate analytical expressions of relaxation rates for a broad variety of spin systems and (2) use these analytical expressions to correct the deviations arising in high-resolution relaxometry experiments. These tools lead to a better understanding of nuclear spin relaxation, which is required to improve the sensitivity of many pulse sequences, and to better characterize motions in macromolecules.
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Affiliation(s)
- Nicolas Bolik-Coulon
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
| | - Pavel Kadeřávek
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Philippe Pelupessy
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | | | - Fabien Ferrage
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
| | - Samuel F Cousin
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
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11
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Smith AA, Ernst M, Meier BH, Ferrage F. Reducing bias in the analysis of solution-state NMR data with dynamics detectors. J Chem Phys 2019; 151:034102. [PMID: 31325945 DOI: 10.1063/1.5111081] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Nuclear magnetic resonance (NMR) is sensitive to dynamics on a wide range of correlation times. Recently, we have shown that analysis of relaxation rates via fitting to a correlation function with a small number of exponential terms could yield a biased characterization of molecular motion in solid-state NMR due to limited sensitivity of experimental data to certain ranges of correlation times. We introduced an alternative approach based on "detectors" in solid-state NMR, for which detector responses characterize motion for a range of correlation times and reduce potential bias resulting from the use of simple models for the motional correlation functions. Here, we show that similar bias can occur in the analysis of solution-state NMR relaxation data. We have thus adapted the detector approach to solution-state NMR, specifically separating overall tumbling motion from internal motions and accounting for contributions of chemical exchange to transverse relaxation. We demonstrate that internal protein motions can be described with detectors when the overall motion and the internal motions are statistically independent. We illustrate the detector analysis on ubiquitin with typical relaxation data sets recorded at a single high magnetic field or at multiple high magnetic fields and compare with results of model-free analysis. We also compare our methodology to LeMaster's method of dynamics analysis.
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Affiliation(s)
- Albert A Smith
- ETH Zurich, Physical Chemistry, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Matthias Ernst
- ETH Zurich, Physical Chemistry, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Beat H Meier
- ETH Zurich, Physical Chemistry, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Fabien Ferrage
- Laboratoire des biomolécules, LBM, Département de chimie, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
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