1
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Schanda P, Haran G. NMR and Single-Molecule FRET Insights into Fast Protein Motions and Their Relation to Function. Annu Rev Biophys 2024; 53:247-273. [PMID: 38346243 DOI: 10.1146/annurev-biophys-070323-022428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
Proteins often undergo large-scale conformational transitions, in which secondary and tertiary structure elements (loops, helices, and domains) change their structures or their positions with respect to each other. Simple considerations suggest that such dynamics should be relatively fast, but the functional cycles of many proteins are often relatively slow. Sophisticated experimental methods are starting to tackle this dichotomy and shed light on the contribution of large-scale conformational dynamics to protein function. In this review, we focus on the contribution of single-molecule Förster resonance energy transfer and nuclear magnetic resonance (NMR) spectroscopies to the study of conformational dynamics. We briefly describe the state of the art in each of these techniques and then point out their similarities and differences, as well as the relative strengths and weaknesses of each. Several case studies, in which the connection between fast conformational dynamics and slower function has been demonstrated, are then introduced and discussed. These examples include both enzymes and large protein machines, some of which have been studied by both NMR and fluorescence spectroscopies.
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Affiliation(s)
- Paul Schanda
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria;
| | - Gilad Haran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel;
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2
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Wayment-Steele HK, Otten R, Pitsawong W, Ojoawo AM, Glaser A, Calderone LA, Kern D. The conformational landscape of fold-switcher KaiB is tuned to the circadian rhythm timescale. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.03.597139. [PMID: 38895306 PMCID: PMC11185700 DOI: 10.1101/2024.06.03.597139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
How can a single protein domain encode a conformational landscape with multiple stably-folded states, and how do those states interconvert? Here, we use real-time and relaxation-dispersion NMR to characterize the conformational landscape of the circadian rhythm protein KaiB from Rhodobacter sphaeroides. Unique among known natural metamorphic proteins, this KaiB variant spontaneously interconverts between two monomeric states: the "Ground" and "Fold-switched" (FS) state. KaiB in its FS state interacts with multiple binding partners, including the central KaiC protein, to regulate circadian rhythms. We find that KaiB itself takes hours to interconvert between the Ground and FS state, underscoring the ability of a single sequence to encode the slow process needed for function. We reveal the rate-limiting step between the Ground and FS state is the cis-trans isomerization of three prolines in the fold-switching region by demonstrating interconversion acceleration by the prolyl isomerase CypA. The interconversion proceeds through a "partially disordered" (PD) state, where the C-terminal half becomes disordered while the N-terminal half remains stably folded. We discovered two additional properties of KaiB's landscape. Firstly, the Ground state experiences cold denaturation: at 4°C, the PD state becomes the majorly populated state. Secondly, the Ground state exchanges with a fourth state, the "Enigma" state, on the millisecond timescale. We combine AlphaFold2-based predictions and NMR chemical shift predictions to predict this "Enigma" state is a beta-strand register shift that eases buried charged residues, and support this structure experimentally. These results provide mechanistic insight in how evolution can design a single sequence that achieves specific timing needed for its function.
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Affiliation(s)
- Hannah K Wayment-Steele
- Department of Biochemistry, Brandeis University and Howard Hughes Medical Institute, Waltham, MA, USA
| | - Renee Otten
- Department of Biochemistry, Brandeis University and Howard Hughes Medical Institute, Waltham, MA, USA
- Present address: Treeline Biosciences, Watertown, MA, USA
| | - Warintra Pitsawong
- Department of Biochemistry, Brandeis University and Howard Hughes Medical Institute, Waltham, MA, USA
- Present address: Biomolecular Discovery, Relay Therapeutics, Cambridge, MA, USA
| | - Adedolapo M Ojoawo
- Department of Biochemistry, Brandeis University and Howard Hughes Medical Institute, Waltham, MA, USA
| | - Andrew Glaser
- Department of Biochemistry, Brandeis University and Howard Hughes Medical Institute, Waltham, MA, USA
| | - Logan A Calderone
- Department of Biochemistry, Brandeis University and Howard Hughes Medical Institute, Waltham, MA, USA
| | - Dorothee Kern
- Department of Biochemistry, Brandeis University and Howard Hughes Medical Institute, Waltham, MA, USA
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3
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Burns D, Khatiwada B, Singh A, Purslow JA, Potoyan DA, Venditti V. An α-ketoglutarate conformational switch controls iron accessibility, activation, and substrate selection of the human FTO protein. Proc Natl Acad Sci U S A 2024; 121:e2404457121. [PMID: 38865275 PMCID: PMC11194561 DOI: 10.1073/pnas.2404457121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 05/20/2024] [Indexed: 06/14/2024] Open
Abstract
The fat mass and obesity-associated fatso (FTO) protein is a member of the Alkb family of dioxygenases and catalyzes oxidative demethylation of N6-methyladenosine (m6A), N1-methyladenosine (m1A), 3-methylthymine (m3T), and 3-methyluracil (m3U) in single-stranded nucleic acids. It is well established that the catalytic activity of FTO proceeds via two coupled reactions. The first reaction involves decarboxylation of alpha-ketoglutarate (αKG) and formation of an oxyferryl species. In the second reaction, the oxyferryl intermediate oxidizes the methylated nucleic acid to reestablish Fe(II) and the canonical base. However, it remains unclear how binding of the nucleic acid activates the αKG decarboxylation reaction and why FTO demethylates different methyl modifications at different rates. Here, we investigate the interaction of FTO with 5-mer DNA oligos incorporating the m6A, m1A, or m3T modifications using solution NMR, molecular dynamics (MD) simulations, and enzymatic assays. We show that binding of the nucleic acid to FTO activates a two-state conformational equilibrium in the αKG cosubstrate that modulates the O2 accessibility of the Fe(II) catalyst. Notably, the substrates that provide better stabilization to the αKG conformation in which Fe(II) is exposed to O2 are demethylated more efficiently by FTO. These results indicate that i) binding of the methylated nucleic acid is required to expose the catalytic metal to O2 and activate the αKG decarboxylation reaction, and ii) the measured turnover of the demethylation reaction (which is an ensemble average over the entire sample) depends on the ability of the methylated base to favor the Fe(II) state accessible to O2.
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Affiliation(s)
- Daniel Burns
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA50011
| | | | - Aayushi Singh
- Department of Chemistry, Iowa State University, Ames, IA50011
| | | | - Davit A. Potoyan
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA50011
- Department of Chemistry, Iowa State University, Ames, IA50011
| | - Vincenzo Venditti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA50011
- Department of Chemistry, Iowa State University, Ames, IA50011
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4
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Tiwari VP, De D, Thapliyal N, Kay LE, Vallurupalli P. Beyond slow two-state protein conformational exchange using CEST: applications to three-state protein interconversion on the millisecond timescale. JOURNAL OF BIOMOLECULAR NMR 2024; 78:39-60. [PMID: 38169015 DOI: 10.1007/s10858-023-00431-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 11/15/2023] [Indexed: 01/05/2024]
Abstract
Although NMR spectroscopy is routinely used to study the conformational dynamics of biomolecules, robust analyses of the data are challenged in cases where exchange is more complex than two-state, such as when a 'visible' major conformer exchanges with two 'invisible' minor states on the millisecond timescale. It is becoming increasingly clear that chemical exchange saturation transfer (CEST) NMR experiments that were initially developed to study systems undergoing slow interconversion are also sensitive to intermediate-fast timescale biomolecular conformational exchange. Here we investigate the utility of the amide 15N CEST experiment to characterise protein three-state exchange occurring on the millisecond timescale by studying the interconversion between the folded (F) state of the FF domain from human HYPA/FBP11 (WT FF) and two of its folding intermediates I1 and I2. Although 15N CPMG experiments are consistent with the F state interconverting with a single minor state on the millisecond timescale, 15N CEST data clearly establish an exchange process between F and a pair of minor states. A unique three-state exchange model cannot be obtained by analysis of 15N CEST data recorded at a single temperature. However, including the relative sign of the difference in the chemical shifts of the two minor states based on a simple two-state analysis of CEST data recorded at multiple temperatures, results in a robust three-state model in which the F, I1 and I2 states interconvert with each other on the millisecond timescale ( k e x , F I 1 ~ 550 s-1, k e x , F I 2 ~ 1200 s-1, k e x , I 1 I 2 ~ 5000 s-1), with I1 and I2 sparsely populated at ~ 0.15% and ~ 0.35%, respectively, at 15 °C. A computationally demanding grid-search of exchange parameter space is not required to extract the best-fit exchange parameters from the CEST data. The utility of the CEST experiment, thus, extends well beyond studies of conformers in slow exchange on the NMR chemical shift timescale, to include systems with interconversion rates on the order of thousands/second.
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Affiliation(s)
- Ved Prakash Tiwari
- Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500046, India
| | - Debajyoti De
- Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500046, India
| | - Nemika Thapliyal
- Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500046, India
| | - Lewis E Kay
- Department of Molecular Genetics, University of Toronto, Toronto, M5S 1A8, Canada.
- Department of Chemistry, University of Toronto, Toronto, ON, M5S 3H6, Canada.
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
| | - Pramodh Vallurupalli
- Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500046, India.
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5
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Khandave NP, Sekhar A, Vallurupalli P. Studying micro to millisecond protein dynamics using simple amide 15N CEST experiments supplemented with major-state R 2 and visible peak-position constraints. JOURNAL OF BIOMOLECULAR NMR 2023; 77:165-181. [PMID: 37300639 PMCID: PMC7615914 DOI: 10.1007/s10858-023-00419-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/10/2023] [Indexed: 06/12/2023]
Abstract
Over the last decade amide 15N CEST experiments have emerged as a popular tool to study protein dynamics that involves exchange between a 'visible' major state and sparsely populated 'invisible' minor states. Although initially introduced to study exchange between states that are in slow exchange with each other (typical exchange rates of, 10 to 400 s-1), they are now used to study interconversion between states on the intermediate to fast exchange timescale while still using low to moderate (5 to 350 Hz) 'saturating' B1 fields. The 15N CEST experiment is very sensitive to exchange as the exchange delay TEX can be quite long (~0.5 s) allowing for a large number of exchange events to occur making it a very powerful tool to detect minor sates populated ([Formula: see text]) to as low as 1%. When systems are in fast exchange and the 15N CEST data has to be described using a model that contains exchange, the exchange parameters are often poorly defined because the [Formula: see text] versus [Formula: see text] and [Formula: see text] versus exchange rate ([Formula: see text]) plots can be quite flat with shallow or no minima and the analysis of such 15N CEST data can lead to wrong estimates of the exchange parameters due to the presence of 'spurious' minima. Here we show that the inclusion of experimentally derived constraints on the intrinsic transverse relaxation rates and the inclusion of visible state peak-positions during the analysis of amide 15N CEST data acquired with moderate B1 values (~50 to ~350 Hz) results in convincing minima in the [Formula: see text] versus [Formula: see text] and the [Formula: see text] versus [Formula: see text] plots even when exchange occurs on the 100 μs timescale. The utility of this strategy is demonstrated on the fast-folding Bacillus stearothermophilus peripheral subunit binding domain that folds with a rate constant ~104 s-1. Here the analysis of 15N CEST data alone results in [Formula: see text] versus [Formula: see text] and [Formula: see text] versus [Formula: see text] plots that contain shallow minima, but the inclusion of visible-state peak positions and restraints on the intrinsic transverse relaxation rates of both states during the analysis of the 15N CEST data results in pronounced minima in the [Formula: see text] versus [Formula: see text] and [Formula: see text] versus [Formula: see text] plots and precise exchange parameters even in the fast exchange regime ([Formula: see text]~5). Using this strategy we find that the folding rate constant of PSBD is invariant (~10,500 s-1) from 33.2 to 42.9 °C while the unfolding rates (~70 to ~500 s-1) and unfolded state populations (~0.7 to ~4.3%) increase with temperature. The results presented here show that protein dynamics occurring on the 10 to 104 s-1 timescale can be studied using amide 15N CEST experiments.
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Affiliation(s)
- Nihar Pradeep Khandave
- Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500046, India
| | - Ashok Sekhar
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, Karnataka, 560012, India
| | - Pramodh Vallurupalli
- Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500046, India.
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6
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Henot F, Rioual E, Favier A, Macek P, Crublet E, Josso P, Brutscher B, Frech M, Gans P, Loison C, Boisbouvier J. Visualizing the transiently populated closed-state of human HSP90 ATP binding domain. Nat Commun 2022; 13:7601. [PMID: 36494347 PMCID: PMC9734131 DOI: 10.1038/s41467-022-35399-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 11/29/2022] [Indexed: 12/13/2022] Open
Abstract
HSP90 are abundant molecular chaperones, assisting the folding of several hundred client proteins, including substrates involved in tumor growth or neurodegenerative diseases. A complex set of large ATP-driven structural changes occurs during HSP90 functional cycle. However, the existence of such structural rearrangements in apo HSP90 has remained unclear. Here, we identify a metastable excited state in the isolated human HSP90α ATP binding domain. We use solution NMR and mutagenesis to characterize structures of both ground and excited states. We demonstrate that in solution the HSP90α ATP binding domain transiently samples a functionally relevant ATP-lid closed state, distant by more than 30 Å from the ground state. NMR relaxation enables to derive information on the kinetics and thermodynamics of this interconversion, while molecular dynamics simulations establish that the ATP-lid in closed conformation is a metastable exited state. The precise description of the dynamics and structures sampled by human HSP90α ATP binding domain provides information for the future design of new therapeutic ligands.
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Affiliation(s)
- Faustine Henot
- grid.4444.00000 0001 2112 9282Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71, avenue des martyrs, F-38044 Grenoble, France
| | - Elisa Rioual
- grid.4444.00000 0001 2112 9282Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71, avenue des martyrs, F-38044 Grenoble, France ,grid.7849.20000 0001 2150 7757Institut Lumière Matière, University of Lyon, Université Claude Bernard Lyon 1, CNRS, F-69622 Villeurbanne, France
| | - Adrien Favier
- grid.4444.00000 0001 2112 9282Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71, avenue des martyrs, F-38044 Grenoble, France
| | - Pavel Macek
- grid.4444.00000 0001 2112 9282Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71, avenue des martyrs, F-38044 Grenoble, France ,NMR-Bio, 5 place Robert Schuman, F-38025 Grenoble, France
| | - Elodie Crublet
- NMR-Bio, 5 place Robert Schuman, F-38025 Grenoble, France
| | - Pierre Josso
- grid.7849.20000 0001 2150 7757Institut Lumière Matière, University of Lyon, Université Claude Bernard Lyon 1, CNRS, F-69622 Villeurbanne, France
| | - Bernhard Brutscher
- grid.4444.00000 0001 2112 9282Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71, avenue des martyrs, F-38044 Grenoble, France
| | - Matthias Frech
- grid.39009.330000 0001 0672 7022Discovery Technologies, Merck KGaA, Frankfurter Straße 250, 64293 Darmstadt, Germany
| | - Pierre Gans
- grid.4444.00000 0001 2112 9282Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71, avenue des martyrs, F-38044 Grenoble, France
| | - Claire Loison
- grid.7849.20000 0001 2150 7757Institut Lumière Matière, University of Lyon, Université Claude Bernard Lyon 1, CNRS, F-69622 Villeurbanne, France
| | - Jerome Boisbouvier
- grid.4444.00000 0001 2112 9282Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71, avenue des martyrs, F-38044 Grenoble, France
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7
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Pandit S. 1 H, 15 N and 13 C chemical shift assignments of the N-terminal domain of the two isoforms of the human apolipoprotein E. BIOMOLECULAR NMR ASSIGNMENTS 2022; 16:191-196. [PMID: 35451799 DOI: 10.1007/s12104-022-10078-3] [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: 10/14/2021] [Accepted: 03/10/2022] [Indexed: 06/14/2023]
Abstract
Apolipoprotein E (ApoE) is one of the major lipid transporters in humans. It is also implicated in pathological conditions like Alzheimer's and cardiovascular diseases. The N-terminal domain of ApoE binds low-density lipoprotein receptors (LDLR) while the C-terminal domain binds to the lipid. I report the backbone and aliphatic side-chain NMR chemical shifts of the N-terminal domain of two isoforms of ApoE, namely ApoE3 NTD (BMRB No. 51,122) and ApoE4 NTD (BMRB No. 51,123) at pH 3.5 (20 °C).
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Affiliation(s)
- Subhendu Pandit
- Tata Institute of Fundamental Research, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, 500107, Hyderabad, India.
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8
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The A39G FF domain folds on a volcano-shaped free energy surface via separate pathways. Proc Natl Acad Sci U S A 2021; 118:2115113118. [PMID: 34764225 DOI: 10.1073/pnas.2115113118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2021] [Indexed: 11/18/2022] Open
Abstract
Conformational dynamics play critical roles in protein folding, misfolding, function, misfunction, and aggregation. While detecting and studying the different conformational states populated by protein molecules on their free energy surfaces (FESs) remain a challenge, NMR spectroscopy has emerged as an invaluable experimental tool to explore the FES of a protein, as conformational dynamics can be probed at atomic resolution over a wide range of timescales. Here, we use chemical exchange saturation transfer (CEST) to detect "invisible" minor states on the energy landscape of the A39G mutant FF domain that exhibited "two-state" folding kinetics in traditional experiments. Although CEST has mostly been limited to studies of processes with rates between ∼5 to 300 s-1 involving sparse states with populations as low as ∼1%, we show that the line broadening that is often associated with minor state dips in CEST profiles can be exploited to inform on additional conformers, with lifetimes an order of magnitude shorter and populations close to 10-fold smaller than what typically is characterized. Our analysis of CEST profiles that exploits the minor state linewidths of the 71-residue A39G FF domain establishes a folding mechanism that can be described in terms of a four-state exchange process between interconverting states spanning over two orders of magnitude in timescale from ∼100 to ∼15,000 μs. A similar folding scheme is established for the wild-type domain as well. The study shows that the folding of this small domain proceeds through a pair of sparse, partially structured intermediates via two discrete pathways on a volcano-shaped FES.
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9
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Gerlach GJ, Carrock R, Stix R, Stollar EJ, Ball KA. A disordered encounter complex is central to the yeast Abp1p SH3 domain binding pathway. PLoS Comput Biol 2020; 16:e1007815. [PMID: 32925900 PMCID: PMC7514057 DOI: 10.1371/journal.pcbi.1007815] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 09/24/2020] [Accepted: 08/15/2020] [Indexed: 12/20/2022] Open
Abstract
Protein-protein interactions are involved in a wide range of cellular processes. These interactions often involve intrinsically disordered proteins (IDPs) and protein binding domains. However, the details of IDP binding pathways are hard to characterize using experimental approaches, which can rarely capture intermediate states present at low populations. SH3 domains are common protein interaction domains that typically bind proline-rich disordered segments and are involved in cell signaling, regulation, and assembly. We hypothesized, given the flexibility of SH3 binding peptides, that their binding pathways include multiple steps important for function. Molecular dynamics simulations were used to characterize the steps of binding between the yeast Abp1p SH3 domain (AbpSH3) and a proline-rich IDP, ArkA. Before binding, the N-terminal segment 1 of ArkA is pre-structured and adopts a polyproline II helix, while segment 2 of ArkA (C-terminal) adopts a 310 helix, but is far less structured than segment 1. As segment 2 interacts with AbpSH3, it becomes more structured, but retains flexibility even in the fully engaged state. Binding simulations reveal that ArkA enters a flexible encounter complex before forming the fully engaged bound complex. In the encounter complex, transient nonspecific hydrophobic and long-range electrostatic contacts form between ArkA and the binding surface of SH3. The encounter complex ensemble includes conformations with segment 1 in both the forward and reverse orientation, suggesting that segment 2 may play a role in stabilizing the correct binding orientation. While the encounter complex forms quickly, the slow step of binding is the transition from the disordered encounter ensemble to the fully engaged state. In this transition, ArkA makes specific contacts with AbpSH3 and buries more hydrophobic surface. Simulating the binding between ApbSH3 and ArkA provides insight into the role of encounter complex intermediates and nonnative hydrophobic interactions for other SH3 domains and IDPs in general.
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Affiliation(s)
- Gabriella J. Gerlach
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, United States
| | - Rachel Carrock
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, United States
| | - Robyn Stix
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, United States
| | - Elliott J. Stollar
- School of Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - K. Aurelia Ball
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, United States
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10
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Ceccon A, Tugarinov V, Clore GM. Kinetics of Fast Tetramerization of the Huntingtin Exon 1 Protein Probed by Concentration-Dependent On-Resonance R1ρ Measurements. J Phys Chem Lett 2020; 11:5643-5648. [PMID: 32589032 PMCID: PMC7377354 DOI: 10.1021/acs.jpclett.0c01636] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
An approach for the quantitative description of the kinetics of very fast exchange processes (τex < 50-100 μs) associated with transient, reversible protein oligomerization, is presented. We show that on-resonance 15N-R1ρ measurements conducted as a function of protein concentration at several spin-lock radio frequency field strengths are indispensable for unambiguous determination of the rate constants for interconversion between monomeric and higher order oligomeric species. The approach is experimentally demonstrated on the study of fast, reversible tetramerization of the full-length Huntingtin exon 1 protein, httex1, responsible for Huntington's disease. Incorporation of concentration-dependent 15N-R2,eff data, obtained from on-resonance R1ρ measurements performed at three spin-lock field strengths, into analysis of the kinetic scheme describing reversible tetramerization of httex1 allowed us to uniquely determine the rate constants of interconversion between the various species. This approach serves as a valuable complement to the existing array of NMR techniques for studying early, transient oligomerization events in protein aggregation pathways.
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Affiliation(s)
- Alberto Ceccon
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-520, United States
| | - Vitali Tugarinov
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-520, United States
| | - G Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-520, United States
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11
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Abrogation of prenucleation, transient oligomerization of the Huntingtin exon 1 protein by human profilin I. Proc Natl Acad Sci U S A 2020; 117:5844-5852. [PMID: 32127471 DOI: 10.1073/pnas.1922264117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human profilin I reduces aggregation and concomitant toxicity of the polyglutamine-containing N-terminal region of the huntingtin protein encoded by exon 1 (httex1) and responsible for Huntington's disease. Here, we investigate the interaction of profilin with httex1 using NMR techniques designed to quantitatively analyze the kinetics and equilibria of chemical exchange at atomic resolution, including relaxation dispersion, exchange-induced shifts, and lifetime line broadening. We first show that the presence of two polyproline tracts in httex1, absent from a shorter huntingtin variant studied previously, modulates the kinetics of the transient branched oligomerization pathway that precedes nucleation, resulting in an increase in the populations of the on-pathway helical coiled-coil dimeric and tetrameric species (τex ≤ 50 to 70 μs), while leaving the population of the off-pathway (nonproductive) dimeric species largely unaffected (τex ∼750 μs). Next, we show that the affinity of a single molecule of profilin to the polyproline tracts is in the micromolar range (K diss ∼ 17 and ∼ 31 μM), but binding of a second molecule of profilin is negatively cooperative, with the affinity reduced ∼11-fold. The lifetime of a 1:1 complex of httex1 with profilin, determined using a shorter huntingtin variant containing only a single polyproline tract, is shown to be on the submillisecond timescale (τ ex ∼ 600 μs and K diss ∼ 50 μM). Finally, we demonstrate that, in stable profilin-httex1 complexes, the productive oligomerization pathway, leading to the formation of helical coiled-coil httex1 tetramers, is completely abolished, and only the pathway resulting in "nonproductive" dimers remains active, thereby providing a mechanistic basis for how profilin reduces aggregation and toxicity of httex1.
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12
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Abstract
RNA recognition frequently results in conformational changes that optimize intermolecular binding. As a consequence, the overall binding affinity of RNA to its binding partners depends not only on the intermolecular interactions formed in the bound state but also on the energy cost associated with changing the RNA conformational distribution. Measuring these "conformational penalties" is, however, challenging because bound RNA conformations tend to have equilibrium populations in the absence of the binding partner that fall outside detection by conventional biophysical methods. In this study we employ as a model system HIV-1 TAR RNA and its interaction with the ligand argininamide (ARG), a mimic of TAR's cognate protein binding partner, the transactivator Tat. We use NMR chemical shift perturbations and relaxation dispersion in combination with Bayesian inference to develop a detailed thermodynamic model of coupled conformational change and ligand binding. Starting from a comprehensive 12-state model of the equilibrium, we estimate the energies of six distinct detectable thermodynamic states that are not accessible by currently available methods. Our approach identifies a minimum of four RNA intermediates that differ in terms of the TAR conformation and ARG occupancy. The dominant bound TAR conformation features two bound ARG ligands and has an equilibrium population in the absence of ARG that is below detection limit. Consequently, even though ARG binds to TAR with an apparent overall weak affinity (Kdapp ≈ 0.2 mM), it binds the prefolded conformation with a Kd in the nM range. Our results show that conformational penalties can be major determinants of RNA-ligand binding affinity as well as a source of binding cooperativity, with important implications for a predictive understanding of how RNA is recognized and for RNA-targeted drug discovery.
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Affiliation(s)
- Nicole I. Orlovsky
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Hashim M. Al-Hashimi
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, United States
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Terrence G. Oas
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, United States
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
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13
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Tugarinov V, Clore GM. Exchange saturation transfer and associated NMR techniques for studies of protein interactions involving high-molecular-weight systems. JOURNAL OF BIOMOLECULAR NMR 2019; 73:461-469. [PMID: 31407202 PMCID: PMC6819251 DOI: 10.1007/s10858-019-00244-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 03/27/2019] [Indexed: 05/15/2023]
Abstract
A brief overview of theoretical and experimental aspects of the Dark state Exchange Saturation Transfer (DEST) and lifetime line broadening ([Formula: see text]) NMR methodologies is presented from a physico-chemical perspective. We describe how the field-dependence of [Formula: see text] can be used for determining the exchange regime on the transverse spin relaxation time-scale. Some limitations of DEST/[Formula: see text] methodology in applications to molecular systems with intermediate molecular weights are discussed, and the means of overcoming these limitations via the use of closely related exchange NMR techniques is presented. Finally, several applications of DEST/[Formula: see text] methodology are described from a methodological viewpoint, with an emphasis on providing examples of how kinetic and relaxation parameters of exchange can be reliably extracted from the experimental data in each particular case.
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Affiliation(s)
- Vitali Tugarinov
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA.
| | - G Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA.
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14
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Toyama Y, Kontani K, Katada T, Shimada I. Conformational landscape alternations promote oncogenic activities of Ras-related C3 botulinum toxin substrate 1 as revealed by NMR. SCIENCE ADVANCES 2019; 5:eaav8945. [PMID: 30891502 PMCID: PMC6415961 DOI: 10.1126/sciadv.aav8945] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/28/2019] [Indexed: 06/09/2023]
Abstract
Ras-related C3 botulinum toxin substrate 1 (Rac1) plays critical roles in the maintenance of cell morphology by cycling between inactive guanosine diphosphate (GDP)-bound and active guanosine triphosphate (GTP)-bound states. Rac1 P29S mutant is known to strongly promote oncogenesis by facilitating its intrinsic GDP dissociation and thereby increasing the level of the GTP-bound state. Here, we used solution nuclear magnetic resonance spectroscopy to investigate the activation mechanism of the oncogenic P29S mutant. We demonstrate that the conformational landscape is markedly altered in the mutant, and the preexisting equilibrium is shifted toward the conformation with reduced affinity for Mg2+ , a cofactor that is critical for maintaining stable GDP binding. Our results suggest that the alternation of the preexisting conformational equilibrium of proteins is one of the fundamental mechanisms underlying their oncogenic activities.
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Affiliation(s)
- Yuki Toyama
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Japan Biological Informatics Consortium (JBiC), Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Kenji Kontani
- Department of Biochemistry, Meiji Pharmaceutical University, Kiyose, Tokyo 204-8588, Japan
| | - Toshiaki Katada
- Molecular Cell Biology Laboratory, Research Institute of Pharmaceutical Sciences, Faculty of Pharmacy, Musashino University, Tokyo 202-8585, Japan
| | - Ichio Shimada
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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15
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Probing initial transient oligomerization events facilitating Huntingtin fibril nucleation at atomic resolution by relaxation-based NMR. Proc Natl Acad Sci U S A 2019; 116:3562-3571. [PMID: 30808748 DOI: 10.1073/pnas.1821216116] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The N-terminal region of the huntingtin protein, encoded by exon-1, comprises an amphiphilic domain (httNT), a polyglutamine (Q n ) tract, and a proline-rich sequence. Polyglutamine expansion results in an aggregation-prone protein responsible for Huntington's disease. Here, we study the earliest events involved in oligomerization of a minimalistic construct, httNTQ7, which remains largely monomeric over a sufficiently long period of time to permit detailed quantitative NMR analysis of the kinetics and structure of sparsely populated [Formula: see text] oligomeric states, yet still eventually forms fibrils. Global fitting of concentration-dependent relaxation dispersion, transverse relaxation in the rotating frame, and exchange-induced chemical shift data reveals a bifurcated assembly mechanism in which the NMR observable monomeric species either self-associates to form a productive dimer (τex ∼ 30 μs, K diss ∼ 0.1 M) that goes on to form a tetramer ([Formula: see text] μs; K diss ∼ 22 μM), or exchanges with a "nonproductive" dimer that does not oligomerize further (τex ∼ 400 μs; K diss ∼ 0.3 M). The excited state backbone chemical shifts are indicative of a contiguous helix (residues 3-17) in the productive dimer/tetramer, with only partial helical character in the nonproductive dimer. A structural model of the productive dimer/tetramer was obtained by simulated annealing driven by intermolecular paramagnetic relaxation enhancement data. The tetramer comprises a D 2 symmetric dimer of dimers with largely hydrophobic packing between the helical subunits. The structural model, validated by EPR distance measurements, illuminates the role of the httNT domain in the earliest stages of prenucleation and oligomerization, before fibril formation.
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16
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Marion D, Gauto DF, Ayala I, Giandoreggio-Barranco K, Schanda P. Microsecond Protein Dynamics from Combined Bloch-McConnell and Near-Rotary-Resonance R 1p Relaxation-Dispersion MAS NMR. Chemphyschem 2019; 20:276-284. [PMID: 30444575 PMCID: PMC6354937 DOI: 10.1002/cphc.201800935] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/15/2018] [Indexed: 12/14/2022]
Abstract
Studying protein dynamics on microsecond-to-millisecond (μs-ms) time scales can provide important insight into protein function. In magic-angle-spinning (MAS) NMR, μs dynamics can be visualized by R 1 ρ rotating-frame relaxation dispersion experiments in different regimes of radio-frequency field strengths: at low RF field strength, isotropic-chemical-shift fluctuation leads to "Bloch-McConnell-type" relaxation dispersion, while when the RF field approaches rotary resonance conditions bond angle fluctuations manifest as increased R 1 ρ rate constants ("Near-Rotary-Resonance Relaxation Dispersion", NERRD). Here we explore the joint analysis of both regimes to gain comprehensive insight into motion in terms of geometric amplitudes, chemical-shift changes, populations and exchange kinetics. We use a numerical simulation procedure to illustrate these effects and the potential of extracting exchange parameters, and apply the methodology to the study of a previously described conformational exchange process in microcrystalline ubiquitin.
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Affiliation(s)
- Dominique Marion
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 71 avenue des martyrs, 38000 Grenoble (France)
| | - Diego F. Gauto
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 71 avenue des martyrs, 38000 Grenoble (France)
| | - Isabel Ayala
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 71 avenue des martyrs, 38000 Grenoble (France)
| | - Karine Giandoreggio-Barranco
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 71 avenue des martyrs, 38000 Grenoble (France)
| | - Paul Schanda
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 71 avenue des martyrs, 38000 Grenoble (France)
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17
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Gopalan AB, Yuwen T, Kay LE, Vallurupalli P. A methyl 1H double quantum CPMG experiment to study protein conformational exchange. JOURNAL OF BIOMOLECULAR NMR 2018; 72:79-91. [PMID: 30276607 DOI: 10.1007/s10858-018-0208-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 09/01/2018] [Indexed: 05/24/2023]
Abstract
Protein conformational changes play crucial roles in enabling function. The Carr-Purcell-Meiboom-Gill (CPMG) experiment forms the basis for studying such dynamics when they involve the interconversion between highly populated and sparsely formed states, the latter having lifetimes ranging from ~ 0.5 to ~ 5 ms. Among the suite of experiments that have been developed are those that exploit methyl group probes by recording methyl 1H single quantum (Tugarinov and Kay in J Am Chem Soc 129:9514-9521, 2007) and triple quantum (Yuwen et al. in Angew Chem Int Ed Engl 55:11490-11494, 2016) relaxation dispersion profiles. Here we build upon these by developing a third experiment in which methyl 1H double quantum coherences evolve during a CPMG relaxation element. By fitting single, double, and triple quantum datasets, akin to recording the single quantum dataset at static magnetic fields of Bo, 2Bo and 3Bo, we show that accurate exchange values can be obtained even in cases where exchange rates exceed 10,000 s-1. The utility of the double quantum experiment is demonstrated with a pair of cavity mutants of T4 lysozyme (T4L) with ground and excited states interchanged and with exchange rates differing by fourfold (~ 900 s-1 and ~ 3600 s-1), as well as with a fast-folding domain where the unfolded state lifetime is ~ 80 µs.
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Affiliation(s)
- Anusha B Gopalan
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, Telangana, 500107, India
| | - Tairan Yuwen
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Lewis E Kay
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada.
| | - Pramodh Vallurupalli
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, Telangana, 500107, India.
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18
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Gopalan AB, Hansen DF, Vallurupalli P. CPMG Experiments for Protein Minor Conformer Structure Determination. Methods Mol Biol 2018; 1688:223-242. [PMID: 29151212 DOI: 10.1007/978-1-4939-7386-6_11] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
CPMG relaxation dispersion NMR experiments have emerged as a powerful method to characterize protein minor states that are in exchange with a visible dominant conformation, and have lifetimes between ~0.5 and 5 milliseconds (ms) and populations greater than 0.5%. The structure of the minor state can, in favorable cases, be determined from the parameters provided by the CPMG relaxation dispersion experiments. Here, we go through the intricacies of setting up these powerful CPMG experiments.
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Affiliation(s)
- Anusha B Gopalan
- TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad, 500075, India.
| | - D Flemming Hansen
- Division of Biosciences, Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK.
| | - Pramodh Vallurupalli
- TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad, 500075, India.
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19
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Khirich G, Holliday MJ, Lin JC, Nandy A. Measurement and Characterization of Hydrogen-Deuterium Exchange Chemistry Using Relaxation Dispersion NMR Spectroscopy. J Phys Chem B 2018; 122:2368-2378. [PMID: 29376350 DOI: 10.1021/acs.jpcb.7b10849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One-dimensional heteronuclear relaxation dispersion NMR spectroscopy at 13C natural abundance successfully characterized the dynamics of the hydrogen-deuterium exchange reaction occurring at the Nε position in l-arginine by monitoring Cδ in varying amounts of D2O. A small equilibrium isotope effect was observed and quantified, corresponding to ΔG = -0.14 kcal mol-1. A bimolecular rate constant of kD = 5.1 × 109 s-1 M-1 was determined from the pH*-dependence of kex (where pH* is the direct electrode reading of pH in 10% D2O and kex is the nuclear spin exchange rate constant), consistent with diffusion-controlled kinetics. The measurement of ΔG serves to bridge the millisecond time scale lifetimes of the detectable positively charged arginine species with the nanosecond time scale lifetime of the nonobservable low-populated neutral arginine intermediate species, thus allowing for characterization of the equilibrium lifetimes of the various arginine species in solution as a function of fractional solvent deuterium content. Despite the system being in fast exchange on the chemical shift time scale, the magnitude of the secondary isotope shift due to the exchange reaction at Nε was accurately measured to be 0.12 ppm directly from curve-fitting D2O-dependent dispersion data collected at a single static field strength. These results indicate that relaxation dispersion NMR spectroscopy is a robust and general method for studying base-catalyzed hydrogen-deuterium exchange chemistry at equilibrium.
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Affiliation(s)
- Gennady Khirich
- Protein Analytical Chemistry, ‡Early Discovery Biochemistry, and §Late Stage Pharmaceutical Development, Genentech, Inc. , 1 DNA Way, South San Francisco, California 94080, United States
| | - Michael J Holliday
- Protein Analytical Chemistry, ‡Early Discovery Biochemistry, and §Late Stage Pharmaceutical Development, Genentech, Inc. , 1 DNA Way, South San Francisco, California 94080, United States
| | - Jasper C Lin
- Protein Analytical Chemistry, ‡Early Discovery Biochemistry, and §Late Stage Pharmaceutical Development, Genentech, Inc. , 1 DNA Way, South San Francisco, California 94080, United States
| | - Aditya Nandy
- Protein Analytical Chemistry, ‡Early Discovery Biochemistry, and §Late Stage Pharmaceutical Development, Genentech, Inc. , 1 DNA Way, South San Francisco, California 94080, United States
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20
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Gopalan AB, Vallurupalli P. Measuring the signs of the methyl 1H chemical shift differences between major and 'invisible' minor protein conformational states using methyl 1H multi-quantum spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2018; 70:187-202. [PMID: 29564579 DOI: 10.1007/s10858-018-0171-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Accepted: 02/21/2018] [Indexed: 06/08/2023]
Abstract
Carr-Purcell-Meiboom-Gill (CPMG) type relaxation dispersion experiments are now routinely used to characterise protein conformational dynamics that occurs on the μs to millisecond (ms) timescale between a visible major state and 'invisible' minor states. The exchange rate(s) ([Formula: see text]), population(s) of the minor state(s) and the absolute value of the chemical shift difference [Formula: see text] (ppm) between different exchanging states can be extracted from the CPMG data. However the sign of [Formula: see text] that is required to reconstruct the spectrum of the 'invisible' minor state(s) cannot be obtained from CPMG data alone. Building upon the recently developed triple quantum (TQ) methyl [Formula: see text] CPMG experiment (Yuwen in Angew Chem 55:11490-11494, 2016) we have developed pulse sequences that use carbon detection to generate and evolve single quantum (SQ), double quantum (DQ) and TQ coherences from methyl protons in the indirect dimension to measure the chemical exchange-induced shifts of the SQ, DQ and TQ coherences from which the sign of [Formula: see text] is readily obtained for two state exchange. Further a combined analysis of the CPMG data and the difference in exchange induced shifts between the SQ and DQ resonances and between the SQ and TQ resonances improves the estimates of exchange parameters like the population of the minor state. We demonstrate the use of these experiments on two proteins undergoing exchange: (1) the ~ 18 kDa cavity mutant of T4 Lysozyme ([Formula: see text]) and (2) the [Formula: see text] kDa Peripheral Sub-unit Binding Domain (PSBD) from the acetyl transferase of Bacillus stearothermophilus ([Formula: see text]).
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Affiliation(s)
- Anusha B Gopalan
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal Ranga Reddy District, Hyderabad, Telangana, 500107, India
| | - Pramodh Vallurupalli
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal Ranga Reddy District, Hyderabad, Telangana, 500107, India.
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21
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Rao Kakita VM, Bopardikar M, Kumar Shukla V, Rachineni K, Ranjan P, Singh JS, Hosur R. An efficient combination of BEST and NUS methods in multidimensional NMR spectroscopy for high throughput analysis of proteins. RSC Adv 2018; 8:17616-17621. [PMID: 35542095 PMCID: PMC9080477 DOI: 10.1039/c8ra00527c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 05/01/2018] [Indexed: 11/23/2022] Open
Abstract
Application of Non Uniform Sampling (NUS) along with Band-selective Excitation Short-Transient (BEST) NMR experiments has been demonstrated for obtaining the important residue-specific atomic level backbone chemical shift values in short durations of time. This application has been demonstrated with both well-folded (ubiquitin) and unfolded (α-synuclein) proteins alike. With this strategy, the experiments required for determining backbone chemical shifts can be performed very rapidly, i.e., in ∼2 hours of spectrometer time, and this data can be used to calculate the backbone folds of proteins using well established algorithms. This will be of great value for structural proteomic investigations on one hand, where the speed of structure determination is a limiting factor and for application in the study of slow kinetic processes involving proteins, such as fibrillization, on the other hand. Application of NUS along with BEST NMR experiments has been demonstrated for obtaining the important residue-specific atomic level backbone chemical shift values in short durations of time.![]()
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Affiliation(s)
| | - Mandar Bopardikar
- Department of Chemical Sciences
- Tata Institute of Fundamental Research (TIFR)
- Mumbai 400 005
- India
| | - Vaibhav Kumar Shukla
- UM-DAE Centre for Excellence in Basic Sciences
- University of Mumbai
- Mumbai 400 098
- India
| | - Kavitha Rachineni
- UM-DAE Centre for Excellence in Basic Sciences
- University of Mumbai
- Mumbai 400 098
- India
| | - Priyatosh Ranjan
- Department of Biosciences & Bioengineering
- Indian Institute of Technology-Bombay (IIT-B)
- Mumbai 400076
- India
| | - Jai Shankar Singh
- Department of Biosciences & Bioengineering
- Indian Institute of Technology-Bombay (IIT-B)
- Mumbai 400076
- India
| | - Ramakrishna V. Hosur
- UM-DAE Centre for Excellence in Basic Sciences
- University of Mumbai
- Mumbai 400 098
- India
- Department of Chemical Sciences
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22
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Reddy JG, Pratihar S, Ban D, Frischkorn S, Becker S, Griesinger C, Lee D. Simultaneous determination of fast and slow dynamics in molecules using extreme CPMG relaxation dispersion experiments. JOURNAL OF BIOMOLECULAR NMR 2018; 70:1-9. [PMID: 29188417 DOI: 10.1007/s10858-017-0155-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/20/2017] [Indexed: 06/07/2023]
Abstract
Molecular dynamics play a significant role in how molecules perform their function. A critical method that provides information on dynamics, at the atomic level, is NMR-based relaxation dispersion (RD) experiments. RD experiments have been utilized for understanding multiple biological processes occurring at micro-to-millisecond time, such as enzyme catalysis, molecular recognition, ligand binding and protein folding. Here, we applied the recently developed high-power RD concept to the Carr-Purcell-Meiboom-Gill sequence (extreme CPMG; E-CPMG) for the simultaneous detection of fast and slow dynamics. Using a fast folding protein, gpW, we have shown that previously inaccessible kinetics can be accessed with the improved precision and efficiency of the measurement by using this experiment.
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Affiliation(s)
- Jithender G Reddy
- Department for NMR-based Structural Biology, Max-Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
- NMR & Structural Chemistry Division, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India
| | - Supriya Pratihar
- Department for NMR-based Structural Biology, Max-Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - David Ban
- Department of Medicine, James Graham Brown Cancer Center, University of Louisville, 505 S. Hancock St, Louisville, KY, 40202, USA
| | - Sebastian Frischkorn
- Department for NMR-based Structural Biology, Max-Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Stefan Becker
- Department for NMR-based Structural Biology, Max-Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Christian Griesinger
- Department for NMR-based Structural Biology, Max-Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Donghan Lee
- Department of Medicine, James Graham Brown Cancer Center, University of Louisville, 505 S. Hancock St, Louisville, KY, 40202, USA.
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23
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Narayanan C, Bafna K, Roux LD, Agarwal PK, Doucet N. Applications of NMR and computational methodologies to study protein dynamics. Arch Biochem Biophys 2017; 628:71-80. [PMID: 28483383 DOI: 10.1016/j.abb.2017.05.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 05/03/2017] [Accepted: 05/04/2017] [Indexed: 02/07/2023]
Abstract
Overwhelming evidence now illustrates the defining role of atomic-scale protein flexibility in biological events such as allostery, cell signaling, and enzyme catalysis. Over the years, spin relaxation nuclear magnetic resonance (NMR) has provided significant insights on the structural motions occurring on multiple time frames over the course of a protein life span. The present review article aims to illustrate to the broader community how this technique continues to shape many areas of protein science and engineering, in addition to being an indispensable tool for studying atomic-scale motions and functional characterization. Continuing developments in underlying NMR technology alongside software and hardware developments for complementary computational approaches now enable methodologies to routinely provide spatial directionality and structural representations traditionally harder to achieve solely using NMR spectroscopy. In addition to its well-established role in structural elucidation, we present recent examples that illustrate the combined power of selective isotope labeling, relaxation dispersion experiments, chemical shift analyses, and computational approaches for the characterization of conformational sub-states in proteins and enzymes.
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Affiliation(s)
- Chitra Narayanan
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boul. des Prairies, Laval, QC H7V 1B7, Canada
| | - Khushboo Bafna
- Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, USA
| | - Louise D Roux
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boul. des Prairies, Laval, QC H7V 1B7, Canada
| | - Pratul K Agarwal
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA; Computational Biology Institute and Computer Science and Mathematics Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37830, USA
| | - Nicolas Doucet
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boul. des Prairies, Laval, QC H7V 1B7, Canada; PROTEO, The Quebec Network for Research on Protein Function, Structure, and Engineering, 1045 Avenue de la Médecine, Université Laval, Québec, QC G1V 0A6, Canada; GRASP, The Groupe de Recherche Axé sur la Structure des Protéines, 3649 Promenade Sir William Osler, McGill University, Montréal, QC H3G 0B1, Canada.
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24
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Vallurupalli P, Sekhar A, Yuwen T, Kay LE. Probing conformational dynamics in biomolecules via chemical exchange saturation transfer: a primer. JOURNAL OF BIOMOLECULAR NMR 2017; 67:243-271. [PMID: 28317074 DOI: 10.1007/s10858-017-0099-4] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 02/20/2017] [Indexed: 05/25/2023]
Abstract
Although Chemical Exchange Saturation Transfer (CEST) type NMR experiments have been used to study chemical exchange processes in molecules since the early 1960s, there has been renewed interest in the past several years in using this approach to study biomolecular conformational dynamics. The methodology is particularly powerful for the study of sparsely populated, transiently formed conformers that are recalcitrant to investigation using traditional biophysical tools, and it is complementary to relaxation dispersion and magnetization transfer experiments that have traditionally been used to study chemical exchange processes. Here we discuss the concepts behind the CEST experiment, focusing on practical aspects as well, we review some of the pulse sequences that have been developed to characterize protein and RNA conformational dynamics, and we discuss a number of examples where the CEST methodology has provided important insights into the role of dynamics in biomolecular function.
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Affiliation(s)
| | - Ashok Sekhar
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, Canada
| | - Tairan Yuwen
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, Canada
| | - Lewis E Kay
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, Canada.
- Hospital for Sick Children, Program in Molecular Structure and Function, Toronto, ON, Canada.
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25
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Toyama Y, Kano H, Mase Y, Yokogawa M, Osawa M, Shimada I. Dynamic regulation of GDP binding to G proteins revealed by magnetic field-dependent NMR relaxation analyses. Nat Commun 2017; 8:14523. [PMID: 28223697 PMCID: PMC5322562 DOI: 10.1038/ncomms14523] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 01/10/2017] [Indexed: 11/30/2022] Open
Abstract
Heterotrimeric guanine-nucleotide-binding proteins (G proteins) serve as molecular switches in signalling pathways, by coupling the activation of cell surface receptors to intracellular responses. Mutations in the G protein α-subunit (Gα) that accelerate guanosine diphosphate (GDP) dissociation cause hyperactivation of the downstream effector proteins, leading to oncogenesis. However, the structural mechanism of the accelerated GDP dissociation has remained unclear. Here, we use magnetic field-dependent nuclear magnetic resonance relaxation analyses to investigate the structural and dynamic properties of GDP bound Gα on a microsecond timescale. We show that Gα rapidly exchanges between a ground-state conformation, which tightly binds to GDP and an excited conformation with reduced GDP affinity. The oncogenic D150N mutation accelerates GDP dissociation by shifting the equilibrium towards the excited conformation. Heterotrimeric guanine-nucleotide-binding proteins (G proteins) act as molecular switches. Here the authors use NMR relaxation analyses, which reveal the dynamics of G protein alpha subunit binding to GDP on a microsecond timescale.
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Affiliation(s)
- Yuki Toyama
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.,Japan Biological Informatics Consortium (JBiC), Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Hanaho Kano
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yoko Mase
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Mariko Yokogawa
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masanori Osawa
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ichio Shimada
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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26
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Fenwick RB, Oyen D, Wright PE. Multi-probe relaxation dispersion measurements increase sensitivity to protein dynamics. Phys Chem Chem Phys 2017; 18:5789-98. [PMID: 26426424 DOI: 10.1039/c5cp04670j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion measurements are a valuable tool for the characterization of structural transitions on the micro-millisecond timescale. While the measurement of (15)N relaxation dispersion is now routine, the measurements with alternative nuclei remain limited. Here we report (15)N as well as (1)H R2 relaxation dispersion measurements of the N23PP/S148A "dynamic knockout" mutant of dihydrofolate reductase. The (1)H dispersion measurements are complementary to (15)N data as many additional residues are observed to have dispersive behavior for the (1)H nucleus. Simultaneous fitting of the dispersion profiles for the two nuclei increases the accuracy of exchange parameters determined for individual residues and clustered groups of residues. The different sensitivity of the two nuclei to changes in backbone torsional angles, ring currents, and hydrogen bonding effects provides important insights into the nature of the structural changes that take place during the exchange process. We observe clear evidence of direct and indirect hydrogen bond effects for the (15)N and (1)H chemical shift changes in the active-site, modulation of ring current shielding in the CD-loop and backbone torsional changes in a cluster of residues associated with the C-terminus. This work demonstrates the power of combined (1)H and (15)N probes for the study of backbone dynamics on the micro-millisecond timescale though the analysis of chemical shift changes.
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Affiliation(s)
- R Bryn Fenwick
- Department of Integrative Structural and Computational Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
| | - David Oyen
- Department of Integrative Structural and Computational Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
| | - Peter E Wright
- Department of Integrative Structural and Computational Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
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27
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Abstract
It is well-established that dynamics are central to protein function; their importance is implicitly acknowledged in the principles of the Monod, Wyman and Changeux model of binding cooperativity, which was originally proposed in 1965. Nowadays the concept of protein dynamics is formulated in terms of the energy landscape theory, which can be used to understand protein folding and conformational changes in proteins. Because protein dynamics are so important, a key to understanding protein function at the molecular level is to design experiments that allow their quantitative analysis. Nuclear magnetic resonance (NMR) spectroscopy is uniquely suited for this purpose because major advances in theory, hardware, and experimental methods have made it possible to characterize protein dynamics at an unprecedented level of detail. Unique features of NMR include the ability to quantify dynamics (i) under equilibrium conditions without external perturbations, (ii) using many probes simultaneously, and (iii) over large time intervals. Here we review NMR techniques for quantifying protein dynamics on fast (ps-ns), slow (μs-ms), and very slow (s-min) time scales. These techniques are discussed with reference to some major discoveries in protein science that have been made possible by NMR spectroscopy.
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28
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Takeda M, Miyanoiri Y, Terauchi T, Kainosho M. (13)C-NMR studies on disulfide bond isomerization in bovine pancreatic trypsin inhibitor (BPTI). JOURNAL OF BIOMOLECULAR NMR 2016; 66:37-53. [PMID: 27566173 DOI: 10.1007/s10858-016-0055-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 08/22/2016] [Indexed: 06/06/2023]
Abstract
Conformational isomerization of disulfide bonds is associated with the dynamics and thus the functional aspects of proteins. However, our understanding of the isomerization is limited by experimental difficulties in probing it. We explored the disulfide conformational isomerization of the Cys14-Cys38 disulfide bond in bovine pancreatic trypsin inhibitor (BPTI), by performing an NMR line-shape analysis of its Cys carbon peaks. In this approach, 1D (13)C spectra were recorded at small temperature intervals for BPTI samples selectively labeled with site-specifically (13)C-enriched Cys, and the recorded peaks were displayed in the order of the temperature after the spectral scales were normalized to a carbon peak. Over the profile of the line-shape, exchange broadening that altered with temperature was manifested for the carbon peaks of Cys14 and Cys38. The Cys14-Cys38 disulfide bond reportedly exists in equilibrium between a high-populated (M) and two low-populated states (m c14 and m c38). Consistent with the three-site exchange model, biphasic exchange broadening arising from the two processes was observed for the peak of the Cys14 α-carbon. As the exchange broadening is maximized when the exchange rate equals the chemical shift difference in Hz between equilibrating sites, semi-quantitative information that was useful for establishing conditions for (13)C relaxation dispersion experiments was obtained through the carbon line-shape profile. With respect to the m c38 isomerization, the (1)H-(13)C signals at the β-position of the minor state were resolved from the major peaks and detected by exchange experiments at a low temperature.
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Affiliation(s)
- Mitsuhiro Takeda
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
- Department of Structural BioImaging, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto, 862-0973, Japan
| | - Yohei Miyanoiri
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Tsutomu Terauchi
- Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, Tokyo, 192-0397, Japan
- SAIL Technologies Inc., 2008-2 Wada, Tama, Tokyo, 206-0001, Japan
| | - Masatsune Kainosho
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan.
- Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, Tokyo, 192-0397, Japan.
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29
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Vallurupalli P, Chakrabarti N, Pomès R, Kay LE. Atomistic picture of conformational exchange in a T4 lysozyme cavity mutant: an experiment-guided molecular dynamics study. Chem Sci 2016; 7:3602-3613. [PMID: 30008994 PMCID: PMC6008728 DOI: 10.1039/c5sc03886c] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/03/2016] [Indexed: 12/16/2022] Open
Abstract
Despite the importance of dynamics to protein function there is little information about the states that are formed as the protein explores its conformational landscape or about the mechanism by which transitions between the different states occur. Here we used a combined NMR spin relaxation and unbiased molecular dynamics (MD) approach to investigate the exchange process by which a cavity in an L99A mutant of T4 lysozyme (T4L 99A) interconverts between an empty and occupied form that involves repositioning of an aromatic residue, Phe114. Although structures of the end-states of the exchange process are available, insight into the mechanism by which the transition takes place cannot be obtained from experiment and the timescales involved are too slow to address using brute force MD. Using spin relaxation NMR methods, we have identified a triple-mutant of T4L that undergoes the same exchange process as T4L L99A but where the minor state lifetime has decreased significantly so that the spontaneous conformational transition to the major state can be studied using all-atom MD simulations. The simulation trajectories were analyzed using Markov state models and the energy landscape so obtained is in good agreement with expectations based on NMR studies. Notably there is no large-scale perturbation of the structure during the transition, multiple intermediates are formed between the two similar exchanging conformations and the free energy barrier between these two well-folded, compact forms is small (6kBT), only slightly larger than for processes considered to be barrierless.
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Affiliation(s)
- Pramodh Vallurupalli
- TIFR Centre for Interdisciplinary Sciences , 21 Brundavan Colony, Narsingi , Hyderabad 500075 , India .
| | - Nilmadhab Chakrabarti
- Molecular Structure and Function , Hospital for Sick Children , Toronto , ON , Canada M5G 1X8
| | - Régis Pomès
- Molecular Structure and Function , Hospital for Sick Children , Toronto , ON , Canada M5G 1X8
- Department of Biochemistry , University of Toronto , Toronto , ON , Canada M5S 1A8
| | - Lewis E Kay
- Molecular Structure and Function , Hospital for Sick Children , Toronto , ON , Canada M5G 1X8
- Department of Biochemistry , University of Toronto , Toronto , ON , Canada M5S 1A8
- Departments of Molecular Genetics and Chemistry , University of Toronto , Toronto , ON M5S 1A8 , Canada .
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30
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Fizil Á, Gáspári Z, Barna T, Marx F, Batta G. "Invisible" conformers of an antifungal disulfide protein revealed by constrained cold and heat unfolding, CEST-NMR experiments, and molecular dynamics calculations. Chemistry 2015; 21:5136-44. [PMID: 25676351 PMCID: PMC4464532 DOI: 10.1002/chem.201404879] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Indexed: 12/12/2022]
Abstract
Transition between conformational states in proteins is being recognized as a possible key factor of function. In support of this, hidden dynamic NMR structures were detected in several cases up to populations of a few percent. Here, we show by two- and three-state analysis of thermal unfolding, that the population of hidden states may weight 20-40 % at 298 K in a disulfide-rich protein. In addition, sensitive (15) N-CEST NMR experiments identified a low populated (0.15 %) state that was in slow exchange with the folded PAF protein. Remarkably, other techniques failed to identify the rest of the NMR "dark matter". Comparison of the temperature dependence of chemical shifts from experiments and molecular dynamics calculations suggests that hidden conformers of PAF differ in the loop and terminal regions and are most similar in the evolutionary conserved core. Our observations point to the existence of a complex conformational landscape with multiple conformational states in dynamic equilibrium, with diverse exchange rates presumably responsible for the completely hidden nature of a considerable fraction.
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Affiliation(s)
- Ádám Fizil
- Department of Organic Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen (Hungary)
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31
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Abstract
Myriad biological processes proceed through states that defy characterization by conventional atomic-resolution structural biological methods. The invisibility of these 'dark' states can arise from their transient nature, low equilibrium population, large molecular weight, and/or heterogeneity. Although they are invisible, these dark states underlie a range of processes, acting as encounter complexes between proteins and as intermediates in protein folding and aggregation. New methods have made these states accessible to high-resolution analysis by nuclear magnetic resonance (NMR) spectroscopy, as long as the dark state is in dynamic equilibrium with an NMR-visible species. These methods - paramagnetic NMR, relaxation dispersion, saturation transfer, lifetime line broadening, and hydrogen exchange - allow the exploration of otherwise invisible states in exchange with a visible species over a range of timescales, each taking advantage of some unique property of the dark state to amplify its effect on a particular NMR observable. In this review, we introduce these methods and explore two specific techniques - paramagnetic relaxation enhancement and dark state exchange saturation transfer - in greater detail.
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Affiliation(s)
- Nicholas J. Anthis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA
| | - G. Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA
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32
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Zhou Y, Yang D. Effects of J couplings and unobservable minor states on kinetics parameters extracted from CEST data. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 249:118-125. [PMID: 25462955 DOI: 10.1016/j.jmr.2014.10.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Revised: 10/16/2014] [Accepted: 10/18/2014] [Indexed: 06/04/2023]
Abstract
Chemical exchange saturation transfer (CEST) experiments have emerged as a powerful tool for characterizing dynamics and sparse populated conformers of protein in slow exchanging systems. We show that J couplings and 'invisible' minor states can cause systematic errors in kinetics parameters and chemical shifts extracted from CEST data. For weakly coupled spin systems, the J coupling effect can be removed using an approximation method. This method is warranted through detailed theoretical derivation, supported by results from simulations and experiments on an acyl carrier protein domain. Simulations demonstrate that the effect of 'invisible' minor states on the extracted kinetics parameters depends on the chemical shifts, populations, exchange rates of the 'invisible' states to the observed major or minor state and exchange models. Moreover, the extracted chemical shifts of the observed minor state can also be influenced by the "invisible" minor states. The presence of an off-pathway folding intermediate in the acyl carrier protein domain explains why the exchange rates obtained with a two-state model from individual residues that displayed only two obvious CEST dips varied significantly and the extracted exchange rates for 15N and 13CO spins located in the same peptide bond could be very different. The approximation method described here simplifies CEST data analysis in many situations where the coupling effect cannot be ignored and decoupling techniques are not desirable. In addition, this study also raises alerts for 'invisible' minor states which can cause errors in not only kinetics parameters but also chemical shifts of the observed minor state.
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Affiliation(s)
- Yang Zhou
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Daiwen Yang
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore.
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33
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Dias DM, Ciulli A. NMR approaches in structure-based lead discovery: recent developments and new frontiers for targeting multi-protein complexes. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 116:101-12. [PMID: 25175337 PMCID: PMC4261069 DOI: 10.1016/j.pbiomolbio.2014.08.012] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 08/06/2014] [Accepted: 08/19/2014] [Indexed: 01/08/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a pivotal method for structure-based and fragment-based lead discovery because it is one of the most robust techniques to provide information on protein structure, dynamics and interaction at an atomic level in solution. Nowadays, in most ligand screening cascades, NMR-based methods are applied to identify and structurally validate small molecule binding. These can be high-throughput and are often used synergistically with other biophysical assays. Here, we describe current state-of-the-art in the portfolio of available NMR-based experiments that are used to aid early-stage lead discovery. We then focus on multi-protein complexes as targets and how NMR spectroscopy allows studying of interactions within the high molecular weight assemblies that make up a vast fraction of the yet untargeted proteome. Finally, we give our perspective on how currently available methods could build an improved strategy for drug discovery against such challenging targets.
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Affiliation(s)
- David M Dias
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Alessio Ciulli
- College of Life Sciences, Division of Biological Chemistry and Drug Discovery, University of Dundee, Dow Street, DD1 5EH, Dundee, UK.
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34
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Bothe JR, Stein ZW, Al-Hashimi HM. Evaluating the uncertainty in exchange parameters determined from off-resonance R1ρ relaxation dispersion for systems in fast exchange. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 244:18-29. [PMID: 24819426 PMCID: PMC4222517 DOI: 10.1016/j.jmr.2014.04.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/08/2014] [Accepted: 04/09/2014] [Indexed: 05/25/2023]
Abstract
Spin relaxation in the rotating frame (R1ρ) is a powerful NMR technique for characterizing fast microsecond timescale exchange processes directed toward short-lived excited states in biomolecules. At the limit of fast exchange, only k(ex)=k(1)+k(-1) and Φex=p(G)p(E)(Δω)(2) can be determined from R1ρ data limiting the ability to characterize the structure and energetics of the excited state conformation. Here, we use simulations to examine the uncertainty with which exchange parameters can be determined for two state systems in intermediate-to-fast exchange using off-resonance R1ρ relaxation dispersion. R1ρ data computed by solving the Bloch-McConnell equations reveals small but significant asymmetry with respect to offset (R1ρ (ΔΩ)≠R1ρ (-ΔΩ)), which is a hallmark of slow-to-intermediate exchange, even under conditions of fast exchange for free precession chemical exchange line broadening (k(ex)/Δω>10). A grid search analysis combined with bootstrap and Monte-Carlo based statistical approaches for estimating uncertainty in exchange parameters reveals that both the sign and magnitude of Δω can be determined at a useful level of uncertainty for systems in fast exchange (k(ex)/Δω<10) but that this depends on the uncertainty in the R1ρ data and requires a thorough examination of the multidimensional variation of χ(2) as a function of exchange parameters. Results from simulations are complemented by analysis of experimental R1ρ data measured in three nucleic acid systems with exchange processes occurring on the slow (k(ex)/Δω=0.2; pE=∼0.7%), fast (k(ex)/Δω=∼10-16; p(E)=∼13%) and very fast (k(ex)=39,000 s(-1)) chemical shift timescales.
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Affiliation(s)
- Jameson R Bothe
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, MI 48109, United States
| | - Zachary W Stein
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, MI 48109, United States
| | - Hashim M Al-Hashimi
- Department of Biochemistry and Chemistry, Duke University School of Medicine, Durham, NC 27710, United States.
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35
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Sanchez-Medina C, Sekhar A, Vallurupalli P, Cerminara M, Muñoz V, Kay LE. Probing the Free Energy Landscape of the Fast-Folding gpW Protein by Relaxation Dispersion NMR. J Am Chem Soc 2014; 136:7444-51. [DOI: 10.1021/ja502705y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Celia Sanchez-Medina
- Centro de Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Darwin 3, Campus
de Cantoblanco, 28049 Madrid, Spain
| | - Ashok Sekhar
- Departments
of Molecular Genetics, Biochemistry, and Chemistry, The University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Pramodh Vallurupalli
- Departments
of Molecular Genetics, Biochemistry, and Chemistry, The University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Michele Cerminara
- Centro de Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Darwin 3, Campus
de Cantoblanco, 28049 Madrid, Spain
| | - Victor Muñoz
- Centro de Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Darwin 3, Campus
de Cantoblanco, 28049 Madrid, Spain
| | - Lewis E. Kay
- Departments
of Molecular Genetics, Biochemistry, and Chemistry, The University of Toronto, Toronto, Ontario, Canada M5S 1A8
- Program
in Molecular Structure and Function, Hospital for Sick Children, 555
University Avenue, Toronto, Ontario, Canada M5G 1X8
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36
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Micura R, Kreutz C, Breuker K. A personal perspective on chemistry-driven RNA research. Biopolymers 2013; 99:1114-23. [PMID: 23754524 PMCID: PMC4477180 DOI: 10.1002/bip.22299] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 05/27/2013] [Indexed: 12/14/2022]
Abstract
In this mini review, we discuss how our understanding of ribonucleic acid (RNA) properties becomes significantly deepened when a broad range of modern chemical and biophysical methods is applied. We span our perspective from RNA solid-phase synthesis and site-specific labeling to single-molecule fluorescence-resonance-energy-transfer imaging and NMR spectroscopy approaches to explore the dynamics of RNA over a broad timescale. We then move on to Fourier-transform-ion-cyclotron-resonance mass spectrometry (FT-ICR-MS) as a powerful technique for RNA sequencing and modification analysis. The novel methodological developments are discussed for selected biological systems that include the thiamine-pyrophosphate riboswitch, HIV and ribosomal A-site RNA, and transfer RNA.
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Affiliation(s)
- Ronald Micura
- Institute of Organic Chemistry, Center for Molecular Biosciences (CMBI), Center for Chemistry and Biomedicine (CCB), University of Innsbruck, Innrain 80-82, Innsbruck, 6020, Austria
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37
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Ban D, Mazur A, Carneiro MG, Sabo TM, Giller K, Koharudin LMI, Becker S, Gronenborn AM, Griesinger C, Lee D. Enhanced accuracy of kinetic information from CT-CPMG experiments by transverse rotating-frame spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2013; 57:73-82. [PMID: 23949308 DOI: 10.1007/s10858-013-9769-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 08/05/2013] [Indexed: 06/02/2023]
Abstract
Micro-to-millisecond motions of proteins transmit pivotal signals for protein function. A powerful technique for the measurement of these motions is nuclear magnetic resonance spectroscopy. One of the most widely used methodologies for this purpose is the constant-time Carr-Purcell-Meiboom-Gill (CT-CPMG) relaxation dispersion experiment where kinetic and structural information can be obtained at atomic resolution. Extraction of accurate kinetics determined from CT-CPMG data requires refocusing frequencies that are much larger than the nuclei's exchange rate between states. We investigated the effect when fast processes are probed by CT-CPMG experiments via simulation and show that if the intrinsic relaxation rate (R(CT-CPMG)(2,0)) is not known a priori the extraction of accurate kinetics is hindered. Errors on the order of 50 % in the exchange rate are attained when processes become fast, but are minimized to 5 % with a priori (CT-CPMG)(2,0)) information. To alleviate this shortcoming, we developed an experimental scheme probing (CT-CPMG)(2,0)) with large amplitude spin-lock fields, which specifically contains the intrinsic proton longitudinal Eigenrelaxation rate. Our approach was validated with ubiquitin and the Oscillatoria agardhii agglutinin (OAA). For OAA, an underestimation of 66 % in the kinetic rates was observed if (CT-CPMG)(2,0)) is not included during the analysis of CT-CPMG data and result in incorrect kinetics and imprecise amplitude information. This was overcome by combining CT-CPMG with (CT-CPMG)(2,0)) measured with a high power R1ρ experiment. In addition, the measurement of (CT-CPMG)(2,0)) removes the ambiguities in choosing between different models that describe CT-CPMG data.
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Affiliation(s)
- David Ban
- Department for NMR-Based Structural Biology, Max-Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
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38
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Weininger U, Blissing AT, Hennig J, Ahlner A, Liu Z, Vogel HJ, Akke M, Lundström P. Protein conformational exchange measured by 1H R1ρ relaxation dispersion of methyl groups. JOURNAL OF BIOMOLECULAR NMR 2013; 57:47-55. [PMID: 23904100 DOI: 10.1007/s10858-013-9764-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Accepted: 07/17/2013] [Indexed: 06/02/2023]
Abstract
Activated dynamics plays a central role in protein function, where transitions between distinct conformations often underlie the switching between active and inactive states. The characteristic time scales of these transitions typically fall in the microsecond to millisecond range, which is amenable to investigations by NMR relaxation dispersion experiments. Processes at the faster end of this range are more challenging to study, because higher RF field strengths are required to achieve refocusing of the exchanging magnetization. Here we describe a rotating-frame relaxation dispersion experiment for (1)H spins in methyl (13)CHD2 groups, which improves the characterization of fast exchange processes. The influence of (1)H-(1)H rotating-frame nuclear Overhauser effects (ROE) is shown to be negligible, based on a comparison of R 1ρ relaxation data acquired with tilt angles of 90° and 35°, in which the ROE is maximal and minimal, respectively, and on samples containing different (1)H densities surrounding the monitored methyl groups. The method was applied to ubiquitin and the apo form of calmodulin. We find that ubiquitin does not exhibit any (1)H relaxation dispersion of its methyl groups at 10 or 25 °C. By contrast, calmodulin shows significant conformational exchange of the methionine methyl groups in its C-terminal domain, as previously demonstrated by (1)H and (13)C CPMG experiments. The present R 1ρ experiment extends the relaxation dispersion profile towards higher refocusing frequencies, which improves the definition of the exchange correlation time, compared to previous results.
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Affiliation(s)
- Ulrich Weininger
- Department of Biophysical Chemistry, Center for Molecular Protein Science, Lund University, P.O. Box 124, 22100, Lund, Sweden
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39
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Probing the transient dark state of substrate binding to GroEL by relaxation-based solution NMR. Proc Natl Acad Sci U S A 2013; 110:11361-6. [PMID: 23798407 DOI: 10.1073/pnas.1305715110] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mechanism whereby the prototypical chaperonin GroEL performs work on substrate proteins has not yet been fully elucidated, hindered by lack of detailed structural and dynamic information on the bound substrate. Previous investigations have produced conflicting reports on the state of GroEL-bound polypeptides, largely due to the transient and dynamic nature of these complexes. Here, we present a unique approach, based on combined analysis of four complementary relaxation-based NMR experiments, to probe directly the "dark" NMR-invisible state of the model, intrinsically disordered, polypeptide amyloid β (Aβ40) bound to GroEL. The four NMR experiments, lifetime line-broadening, dark-state exchange saturation transfer, relaxation dispersion, and small exchange-induced chemical shifts, are dependent in different ways on the overall exchange rates and populations of the free and bound states of the substrate, as well as on residue-specific dynamics and structure within the bound state as reported by transverse magnetization relaxation rates and backbone chemical shifts, respectively. Global fitting of all the NMR data shows that the complex is transient with a lifetime of <1 ms, that binding involves two predominantly hydrophobic segments corresponding to predicted GroEL consensus binding sequences, and that the structure of the bound polypeptide remains intrinsically and dynamically disordered with minimal changes in secondary structure propensity relative to the free state. Our results establish a unique method to observe NMR-invisible dynamic states of GroEL-bound substrates and to describe at atomic resolution the events between substrate binding and encapsulation that are crucial for understanding the normal and stress-related metabolic function of chaperonins.
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Resetca D, Wilson DJ. Characterizing rapid, activity-linked conformational transitions in proteins via sub-second hydrogen deuterium exchange mass spectrometry. FEBS J 2013; 280:5616-25. [DOI: 10.1111/febs.12332] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 04/26/2013] [Accepted: 05/01/2013] [Indexed: 01/01/2023]
Affiliation(s)
- Diana Resetca
- Department of Chemistry; York University; Toronto Ontario Canada
| | - Derek J. Wilson
- Department of Chemistry; York University; Toronto Ontario Canada
- Center for Research in Mass Spectrometry; Department of Chemistry; York University; Toronto Ontario Canada
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Hansen AL, Bouvignies G, Kay LE. Probing slowly exchanging protein systems via ¹³Cα-CEST: monitoring folding of the Im7 protein. JOURNAL OF BIOMOLECULAR NMR 2013; 55:279-289. [PMID: 23386228 DOI: 10.1007/s10858-013-9711-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 01/20/2013] [Indexed: 06/01/2023]
Abstract
A¹³C(α) chemical exchange saturation transfer based experiment is presented for the study of protein systems undergoing slow interconversion between an 'observable' ground state and one or more 'invisible' excited states. Here a labeling strategy whereby [2-(13)C]-glucose is the sole carbon source is exploited, producing proteins with ¹³C at the C(α) position, while the majority of residues remain unlabeled at CO or C(β). The new experiment is demonstrated with an application to the folding reaction of the Im7 protein that involves an on-pathway excited state. The obtained excited state (13)C(α) chemical shifts are cross validated by comparison to values extracted from analysis of CPMG relaxation dispersion profiles, establishing the utility of the methodology.
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Affiliation(s)
- Alexandar L Hansen
- Department of Molecular Genetics, The University of Toronto, Toronto, ON, M5S 1A8, Canada
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42
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Abstract
The visualization of RNA conformational changes has provided fundamental insights into how regulatory RNAs carry out their biological functions. The RNA structural transitions that have been characterized to date involve long-lived species that can be captured by structure characterization techniques. Here, we report the Nuclear Magnetic Resonance visualization of RNA transitions towards invisible ‘excited states’ (ES), which exist in too little abundance (2–13%) and for too short periods of time (45–250 μs) to allow structural characterization by conventional techniques. Transitions towards ESs result in localized rearrangements in base-pairing that alter building block elements of RNA architecture, including helix-junction-helix motifs and apical loops. The ES can inhibit function by sequestering residues involved in recognition and signaling or promote ATP-independent strand exchange. Thus, RNAs do not adopt a single conformation, but rather exist in rapid equilibrium with alternative ESs, which can be stabilized by cellular cues to affect functional outcomes.
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Vallurupalli P, Bouvignies G, Kay LE. Studying “Invisible” Excited Protein States in Slow Exchange with a Major State Conformation. J Am Chem Soc 2012; 134:8148-61. [DOI: 10.1021/ja3001419] [Citation(s) in RCA: 353] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pramodh Vallurupalli
- Departments of Molecular
Genetics,
Biochemistry, and Chemistry, The University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Guillaume Bouvignies
- Departments of Molecular
Genetics,
Biochemistry, and Chemistry, The University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Lewis E. Kay
- Departments of Molecular
Genetics,
Biochemistry, and Chemistry, The University of Toronto, Toronto, Ontario, Canada M5S 1A8
- Program in Molecular Structure
and Function, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8
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Berlow RB, Swain M, Dalal S, Sweasy JB, Loria JP. Substrate-dependent millisecond domain motions in DNA polymerase β. J Mol Biol 2012; 419:171-82. [PMID: 22446382 DOI: 10.1016/j.jmb.2012.03.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 03/12/2012] [Accepted: 03/13/2012] [Indexed: 02/02/2023]
Abstract
DNA polymerase β (Pol β) is a 39-kDa enzyme that performs the vital cellular function of repairing damaged DNA. Mutations in Pol β have been linked to various cancers, and these mutations are further correlated with altered Pol β enzymatic activity. The fidelity of correct nucleotide incorporation into damaged DNA is essential for Pol β repair function, and several studies have implicated conformational changes in Pol β as a determinant of this repair fidelity. In this work, the rate constants for domain motions in Pol β have been determined by solution NMR relaxation dispersion for the apo and substrate-bound, binary forms of Pol β. In apo Pol β, molecular motions, primarily isolated to the DNA lyase domain, are observed to occur at 1400 s(-1). Additional analysis suggests that these motions allow apo Pol β to sample a conformation similar to the gapped DNA-substrate-bound form. Upon binding DNA, these lyase domain motions are significantly quenched, whereas evidence for conformational motions in the polymerase domain becomes apparent. These NMR studies suggest an alteration in the dynamic landscape of Pol β due to substrate binding. Moreover, a number of the flexible residues identified in this work are also the location of residues, which upon mutation lead to cancer phenotypes in vivo, which may be due to the intimate role of protein motions in Pol β fidelity.
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Affiliation(s)
- Rebecca B Berlow
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
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