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Cui Y, Jin Y, Hou Y, Han X, Cao H, Kay LE, Yuwen T. Optimization of TROSY- and anti-TROSY-based 15N CPMG relaxation dispersion experiments through phase cycling. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 361:107629. [PMID: 38503148 DOI: 10.1016/j.jmr.2024.107629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 01/26/2024] [Accepted: 01/27/2024] [Indexed: 03/21/2024]
Abstract
CPMG relaxation dispersion studies of biomolecular dynamics on the μs-ms timescale can provide detailed kinetic, thermodynamic, and structural insights into function. Frequently, the 15N spin serves as the probe of choice, as uniform incorporation of the 15N isotope is facile and cost-effective, and the interpretation of the resulting data is often relatively straightforward. In conventional CPMG relaxation dispersion experiments the application of CPMG pulses with constant radiofrequency (RF) phase can lead to artifactual dispersion profiles that result from off-resonance effects, RF field inhomogeneity, and pulse miscalibration. The development of CPMG experiments with the [0013]-phase cycle has significantly reduced the impact of pulse imperfections over a greater bandwidth of frequency offsets in comparison to constant phase experiments. Application of 15N-TROSY-based CPMG schemes to studies of the dynamics of large molecules is necessary for high sensitivity, yet the correct incorporation of the [0013]-phase cycle is non-trivial. Here we present TROSY- and anti-TROSY-based 15N CPMG experiments with the [0013]-phase cycling scheme and demonstrate, through comprehensive numerical simulations and experimental validation, enhanced resistance to pulse imperfections relative to traditional schemes utilizing constant phase CPMG pulses. Notably, exchange parameters derived from the new experiments are in good agreement with those obtained using other, more established, 15N-based CPMG approaches.
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Affiliation(s)
- Yingxian Cui
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmaceutical Analysis, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Yangzhuoyue Jin
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmaceutical Analysis, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Yu Hou
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmaceutical Analysis, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Xiaoxu Han
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmaceutical Analysis, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Haiyan Cao
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmaceutical Analysis, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Lewis E Kay
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada; Program in Molecular Medicine, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 1X8, Canada.
| | - Tairan Yuwen
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmaceutical Analysis, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China.
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2
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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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3
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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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4
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Olivieri C, Li GC, Wang Y, V.S. M, Walker C, Kim J, Camilloni C, De Simone A, Vendruscolo M, Bernlohr DA, Taylor SS, Veglia G. ATP-competitive inhibitors modulate the substrate binding cooperativity of a kinase by altering its conformational entropy. SCIENCE ADVANCES 2022; 8:eabo0696. [PMID: 35905186 PMCID: PMC9337769 DOI: 10.1126/sciadv.abo0696] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
ATP-competitive inhibitors are currently the largest class of clinically approved drugs for protein kinases. By targeting the ATP-binding pocket, these compounds block the catalytic activity, preventing substrate phosphorylation. A problem with these drugs, however, is that inhibited kinases may still recognize and bind downstream substrates, acting as scaffolds or binding hubs for signaling partners. Here, using protein kinase A as a model system, we show that chemically different ATP-competitive inhibitors modulate the substrate binding cooperativity by tuning the conformational entropy of the kinase and shifting the populations of its conformationally excited states. Since we found that binding cooperativity and conformational entropy of the enzyme are correlated, we propose a new paradigm for the discovery of ATP-competitive inhibitors, which is based on their ability to modulate the allosteric coupling between nucleotide and substrate-binding sites.
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Affiliation(s)
- Cristina Olivieri
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Geoffrey C. Li
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yingjie Wang
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518055, China
| | - Manu V.S.
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Caitlin Walker
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jonggul Kim
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Carlo Camilloni
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano 20133, Italy
| | - Alfonso De Simone
- Department of Pharmacy, Università degli Studi di Napoli Federico II, Napoli 80131, Italy
| | | | - David A. Bernlohr
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Susan S. Taylor
- Department of Chemistry and Biochemistry, and Pharmacology, University of California at San Diego, CA 92093, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
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5
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Jaroszewicz M, Altenhof AR, Schurko RW, Frydman L. Sensitivity Enhancement by Progressive Saturation of the Proton Reservoir: A Solid-State NMR Analogue of Chemical Exchange Saturation Transfer. J Am Chem Soc 2021; 143:19778-19784. [PMID: 34793152 PMCID: PMC8640991 DOI: 10.1021/jacs.1c08277] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Indexed: 01/10/2023]
Abstract
Chemical exchange saturation transfer (CEST) enhances solution-state NMR signals of labile and otherwise invisible chemical sites, by indirectly detecting their signatures as a highly magnified saturation of an abundant resonance─for instance, the 1H resonance of water. Stimulated by this sensitivity magnification, this study presents PROgressive Saturation of the Proton Reservoir (PROSPR), a method for enhancing the NMR sensitivity of dilute heteronuclei in static solids. PROSPR aims at using these heteronuclei to progressively deplete the abundant 1H polarization found in most organic and several inorganic solids, and implements this 1H signal depletion in a manner that reflects the spectral intensities of the heteronuclei as a function of their chemical shifts or quadrupolar offsets. To achieve this, PROSPR uses a looped cross-polarization scheme that repeatedly depletes 1H-1H local dipolar order and then relays this saturation throughout the full 1H reservoir via spin-diffusion processes that act as analogues of chemical exchanges in the CEST experiment. Repeating this cross-polarization/spin-diffusion procedure multiple times results in an effective magnification of each heteronucleus's response that, when repeated in a frequency-stepped fashion, indirectly maps their NMR spectrum as sizable attenuations of the abundant 1H NMR signal. Experimental PROSPR examples demonstrate that, in this fashion, faithful wideline NMR spectra can be obtained. These 1H-detected heteronuclear NMR spectra can have their sensitivity enhanced by orders of magnitude in comparison to optimized direct-detect experiments targeting unreceptive nuclei at low natural abundance, using modest hardware requirements and conventional NMR equipment at room temperature.
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Affiliation(s)
- Michael
J. Jaroszewicz
- Department
of Chemical and Biological Physics, Weizmann
Institute of Science, Rehovot 7610001, Israel
| | - Adam R. Altenhof
- Department
of Chemistry and Biochemistry, Florida State
University, Tallahassee, Florida 32306, United States
- National
High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Robert W. Schurko
- Department
of Chemistry and Biochemistry, Florida State
University, Tallahassee, Florida 32306, United States
- National
High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Lucio Frydman
- Department
of Chemical and Biological Physics, Weizmann
Institute of Science, Rehovot 7610001, Israel
- National
High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
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6
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Opening of a cryptic pocket in β-lactamase increases penicillinase activity. Proc Natl Acad Sci U S A 2021; 118:2106473118. [PMID: 34799442 PMCID: PMC8617505 DOI: 10.1073/pnas.2106473118] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2021] [Indexed: 11/18/2022] Open
Abstract
A protein is a shape-shifter, but it is currently unclear which of the many structures a protein can adopt are relevant for its function. Here, we examine conformations that contain a “cryptic” pocket (i.e., a pocket absent in ligand-free structures). Cryptic pockets have potential utility in drug discovery efforts because they provide a means to target “undruggable” proteins (i.e., proteins lacking known pockets) or enhance rather than inhibit protein function. In this study, we use a combination of thiol-labeling and kinetic assays, NMR, and molecular dynamic simulations to identify the function of the Ω-loop cryptic pocket in β-lactamase enzymes. We find that an open pocket population is beneficial for hydrolysis of the substrate benzylpenicillin. Understanding the functional role of protein-excited states has important implications in protein design and drug discovery. However, because these states are difficult to find and study, it is still unclear if excited states simply result from thermal fluctuations and generally detract from function or if these states can actually enhance protein function. To investigate this question, we consider excited states in β-lactamases and particularly a subset of states containing a cryptic pocket which forms under the Ω-loop. Given the known importance of the Ω-loop and the presence of this pocket in at least two homologs, we hypothesized that these excited states enhance enzyme activity. Using thiol-labeling assays to probe Ω-loop pocket dynamics and kinetic assays to probe activity, we find that while this pocket is not completely conserved across β-lactamase homologs, those with the Ω-loop pocket have a higher activity against the substrate benzylpenicillin. We also find that this is true for TEM β-lactamase variants with greater open Ω-loop pocket populations. We further investigate the open population using a combination of NMR chemical exchange saturation transfer experiments and molecular dynamics simulations. To test our understanding of the Ω-loop pocket’s functional role, we designed mutations to enhance/suppress pocket opening and observed that benzylpenicillin activity is proportional to the probability of pocket opening in our designed variants. The work described here suggests that excited states containing cryptic pockets can be advantageous for function and may be favored by natural selection, increasing the potential utility of such cryptic pockets as drug targets.
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7
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Xiang X, Hansen AL, Yu L, Jameson G, Bruschweiler-Li L, Yuan C, Brüschweiler R. Observation of Sub-Microsecond Protein Methyl-Side Chain Dynamics by Nanoparticle-Assisted NMR Spin Relaxation. J Am Chem Soc 2021; 143:13593-13604. [PMID: 34428032 DOI: 10.1021/jacs.1c04687] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Amino-acid side-chain properties in proteins are key determinants of protein function. NMR spin relaxation of side chains is an important source of information about local protein dynamics and flexibility. However, traditional solution NMR relaxation methods are most sensitive to sub-nanosecond dynamics lacking information on slower ns-μs time-scale motions. Nanoparticle-assisted NMR spin relaxation (NASR) of methyl-side chains is introduced here as a window into these ns-μs dynamics. NASR utilizes the transient and nonspecific interactions between folded proteins and slowly tumbling spherical nanoparticles (NPs), whereby the increase of the relaxation rates reflects motions on time scales from ps all the way to the overall tumbling correlation time of the NPs ranging from hundreds of ns to μs. The observed motional amplitude of each methyl group can then be expressed by a model-free NASR S2 order parameter. The method is demonstrated for 2H-relaxation of CH2D methyl moieties and cross-correlated relaxation of CH3 groups for proteins Im7 and ubiquitin in the presence of anionic silica-nanoparticles. Both types of relaxation experiments, dominated by either quadrupolar or dipolar interactions, yield highly consistent results. Im7 shows additional dynamics on the intermediate time scales taking place in a functionally important loop, whereas ubiquitin visits the majority of its conformational substates on the sub-ns time scale. These experimental observations are in good agreement with 4-10 μs all-atom molecular dynamics trajectories. NASR probes side-chain dynamics on a much wider range of motional time scales than previously possible, thereby providing new insights into the interplay between protein structure, dynamics, and molecular interactions that govern protein function.
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Affiliation(s)
- Xinyao Xiang
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Alexandar L Hansen
- Campus Chemical Instrument Center, The Ohio State University, Columbus, Ohio 43210, United States
| | - Lei Yu
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Gregory Jameson
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Lei Bruschweiler-Li
- Campus Chemical Instrument Center, The Ohio State University, Columbus, Ohio 43210, United States
| | - Chunhua Yuan
- Campus Chemical Instrument Center, The Ohio State University, Columbus, Ohio 43210, United States
| | - Rafael Brüschweiler
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.,Campus Chemical Instrument Center, The Ohio State University, Columbus, Ohio 43210, United States.,Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio 43210, United States
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8
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Liu B, Shi H, Rangadurai A, Nussbaumer F, Chu CC, Erharter KA, Case DA, Kreutz C, Al-Hashimi HM. A quantitative model predicts how m 6A reshapes the kinetic landscape of nucleic acid hybridization and conformational transitions. Nat Commun 2021; 12:5201. [PMID: 34465779 PMCID: PMC8408185 DOI: 10.1038/s41467-021-25253-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 07/21/2021] [Indexed: 11/18/2022] Open
Abstract
N6-methyladenosine (m6A) is a post-transcriptional modification that controls gene expression by recruiting proteins to RNA sites. The modification also slows biochemical processes through mechanisms that are not understood. Using temperature-dependent (20°C-65°C) NMR relaxation dispersion, we show that m6A pairs with uridine with the methylamino group in the anti conformation to form a Watson-Crick base pair that transiently exchanges on the millisecond timescale with a singly hydrogen-bonded low-populated (1%) mismatch-like conformation in which the methylamino group is syn. This ability to rapidly interchange between Watson-Crick or mismatch-like forms, combined with different syn:anti isomer preferences when paired (~1:100) versus unpaired (~10:1), explains how m6A robustly slows duplex annealing without affecting melting at elevated temperatures via two pathways in which isomerization occurs before or after duplex annealing. Our model quantitatively predicts how m6A reshapes the kinetic landscape of nucleic acid hybridization and conformational transitions, and provides an explanation for why the modification robustly slows diverse cellular processes.
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Affiliation(s)
- Bei Liu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Honglue Shi
- Department of Chemistry, Duke University, Durham, NC, USA
| | - Atul Rangadurai
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Felix Nussbaumer
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria
| | - Chia-Chieh Chu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
- Department of Chemistry, University of Chicago, Chicago, IL, USA
| | - Kevin Andreas Erharter
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria
| | - David A Case
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria
| | - Hashim M Al-Hashimi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA.
- Department of Chemistry, Duke University, Durham, NC, USA.
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9
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The Picornavirus Precursor 3CD Has Different Conformational Dynamics Compared to 3C pro and 3D pol in Functionally Relevant Regions. Viruses 2021; 13:v13030442. [PMID: 33803479 PMCID: PMC8001691 DOI: 10.3390/v13030442] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/06/2021] [Accepted: 03/08/2021] [Indexed: 02/07/2023] Open
Abstract
Viruses have evolved numerous strategies to maximize the use of their limited genetic material, including proteolytic cleavage of polyproteins to yield products with different functions. The poliovirus polyprotein 3CD is involved in important protein-protein, protein-RNA and protein-lipid interactions in viral replication and infection. It is a precursor to the 3C protease and 3D RNA-dependent RNA polymerase, but has different protease specificity, is not an active polymerase, and participates in other interactions differently than its processed products. These functional differences are poorly explained by the known X-ray crystal structures. It has been proposed that functional differences might be due to differences in conformational dynamics between 3C, 3D and 3CD. To address this possibility, we conducted nuclear magnetic resonance spectroscopy experiments, including multiple quantum relaxation dispersion, chemical exchange saturation transfer and methyl spin-spin relaxation, to probe conformational dynamics across multiple timescales. Indeed, these studies identified differences in conformational dynamics in functionally important regions, including enzyme active sites, and RNA and lipid binding sites. Expansion of the conformational ensemble available to 3CD may allow it to perform additional functions not observed in 3C and 3D alone despite having nearly identical lowest-energy structures.
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10
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Xia Y, Yuwen T, Liu A, Kalodimos CG. Removal of 2H-decoupling sidebands in 13CHD 2 13C-CEST profiles. JOURNAL OF BIOMOLECULAR NMR 2021; 75:133-142. [PMID: 33745068 PMCID: PMC8342043 DOI: 10.1007/s10858-021-00362-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 03/08/2021] [Indexed: 05/11/2023]
Abstract
A unique aspect of NMR is its capacity to provide integrated insight into both the structure and intrinsic dynamics of biomolecules. Chemical exchange phenomena that often serve as probes of dynamic processes in biological macromolecules can be quantitatively investigated with chemical exchange saturation transfer (CEST) experiments. 2H-decoupling sidebands, however, always occur in the profiles of 13CHD2 13C-CEST experiments when using the simple CW (continuous wave) method, which may obscure the detection of minor dips of excited states. Traditionally, these sidebands are manually eliminated from the profiles before data analysis by removing experimental points in the range of 2H-decoupling field strength ±50 Hz away from the major dips of the ground state on either side of the dips. Unfortunately, this may also eliminate potential minor dips if they overlap with the decoupling sidebands. Here, we developed methods that use pseudo-continuous waves with variable RF amplitudes distributed onto ramps for 2H decoupling. The new methods were thoroughly validated on Bruker spectrometers at a range of fields (1H frequencies of 600, 700, and 850 MHz, and 1.1 GHz). By using these methods, we successfully removed the sidebands from the NMR profiles of 13CHD2 13C-CEST experiments.
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Affiliation(s)
- Youlin Xia
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
| | - Tairan Yuwen
- Department of Pharmaceutical Analysis & State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Aizhuo Liu
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Charalampos G Kalodimos
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
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11
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Liu G, van Zijl PC. CEST (Chemical Exchange Saturation Transfer) MR Molecular Imaging. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00012-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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12
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Shusterman-Krush R, Grimm L, Avram L, Biedermann F, Bar-Shir A. Elucidating dissociation activation energies in host-guest assemblies featuring fast exchange dynamics. Chem Sci 2020; 12:865-871. [PMID: 34163853 PMCID: PMC8179218 DOI: 10.1039/d0sc05666a] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The ability to mediate the kinetic properties and dissociation activation energies (E a) of bound guests by controlling the characteristics of "supramolecular lids" in host-guest molecular systems is essential for both their design and performance. While the synthesis of such systems is well advanced, the experimental quantification of their kinetic parameters, particularly in systems experiencing fast association and dissociation dynamics, has been very difficult or impossible with the established methods at hand. Here, we demonstrate the utility of the NMR-based guest exchange saturation transfer (GEST) approach for quantifying the dissociation exchange rates (k out) and activation energy (E a,out) in host-guest systems featuring fast dissociation dynamics. Our assessment of the effect of different monovalent cations on the extracted E a,out in cucurbit[7]uril:guest systems with very fast k out highlights their role as "supramolecular lids" in mediating a guest's dissociation E a. We envision that GEST could be further extended to study kinetic parameters in other supramolecular systems characterized by fast kinetic properties and to design novel switchable host-guest assemblies.
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Affiliation(s)
| | - Laura Grimm
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT) Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen Germany
| | - Liat Avram
- Department of Chemical Research Support, Weizmann Institute of Science Rehovot 7610001 Israel
| | - Frank Biedermann
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT) Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen Germany
| | - Amnon Bar-Shir
- Department of Organic Chemistry, Weizmann Institute of Science Rehovot 7610001 Israel
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13
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Boeszoermenyi A, Ogórek B, Jain A, Arthanari H, Wagner G. The precious fluorine on the ring: fluorine NMR for biological systems. JOURNAL OF BIOMOLECULAR NMR 2020; 74:365-379. [PMID: 32651751 PMCID: PMC7539674 DOI: 10.1007/s10858-020-00331-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/29/2020] [Indexed: 05/08/2023]
Abstract
The fluorine-19 nucleus was recognized early to harbor exceptional properties for NMR spectroscopy. With 100% natural abundance, a high gyromagnetic ratio (83% sensitivity compared to 1H), a chemical shift that is extremely sensitive to its surroundings and near total absence in biological systems, it was destined to become a favored NMR probe, decorating small and large molecules. However, after early excitement, where uptake of fluorinated aromatic amino acids was explored in a series of animal studies, 19F-NMR lost popularity, especially in large molecular weight systems, due to chemical shift anisotropy (CSA) induced line broadening at high magnetic fields. Recently, two orthogonal approaches, (i) CF3 labeling and (ii) aromatic 19F-13C labeling leveraging the TROSY (Transverse Relaxation Optimized Spectroscopy) effect have been successfully applied to study large biomolecular systems. In this perspective, we will discuss the fascinating early work with fluorinated aromatic amino acids, which reveals the enormous potential of these non-natural amino acids in biological NMR and the potential of 19F-NMR to characterize protein and nucleic acid structure, function and dynamics in the light of recent developments. Finally, we explore how fluorine NMR might be exploited to implement small molecule or fragment screens that resemble physiological conditions and discuss the opportunity to follow the fate of small molecules in living cells.
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Affiliation(s)
- Andras Boeszoermenyi
- Department of Cancer Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA, 02215, USA.
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA, 02115, USA.
| | - Barbara Ogórek
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital and, Harvard Medical School, Boston, MA, 02115, USA
| | - Akshay Jain
- Department of Cancer Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA, 02215, USA
| | - Haribabu Arthanari
- Department of Cancer Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA, 02215, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA, 02115, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA, 02115, USA.
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14
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Tiwari VP, Vallurupalli P. A CEST NMR experiment to obtain glycine 1H α chemical shifts in 'invisible' minor states of proteins. JOURNAL OF BIOMOLECULAR NMR 2020; 74:443-455. [PMID: 32696193 DOI: 10.1007/s10858-020-00336-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 07/11/2020] [Indexed: 06/11/2023]
Abstract
Chemical exchange saturation transfer (CEST) experiments are routinely used to study protein conformational exchange between a 'visible' major state and 'invisible' minor states because they can detect minor states with lifetimes varying from ~ 3 to ~ 100 ms populated to just ~ 0.5%. Consequently several 1H, 15N and 13C CEST experiments have been developed to study exchange and obtain minor state chemical shifts at almost all backbone and sidechain sites in proteins. Conspicuously missing from this extensive set of CEST experiments is a 1H CEST experiment to study exchange at glycine (Gly) 1Hα sites as the existing 1H CEST experiments that have been designed to study dynamics in amide 1H-15N spin systems and methyl 13CH3 groups with three equivalent protons while suppressing 1H-1H NOE induced dips are not suitable for studying exchange in methylene 13CH2 groups with inequivalent protons. Here a Gly 1Hα CEST experiment to obtain the minor state Gly 1Hα chemical shifts is presented. The utility of this experiment is demonstrated on the L99A cavity mutant of T4 Lysozyme (T4L L99A) that undergoes conformational exchange between two compact conformers. The CEST derived minor state Gly 1Hα chemical shifts of T4L L99A are in agreement with those obtained previously using CPMG techniques. The experimental strategy presented here can also be used to obtain methylene proton minor state chemical shifts from protein sidechain and nucleic acid backbone sites.
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Affiliation(s)
- Ved Prakash Tiwari
- Tata Institute of Fundamental Research, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, Telangana, 500107, India
| | - Pramodh Vallurupalli
- Tata Institute of Fundamental Research, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, Telangana, 500107, India.
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15
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Abramov G, Velyvis A, Rennella E, Wong LE, Kay LE. A methyl-TROSY approach for NMR studies of high-molecular-weight DNA with application to the nucleosome core particle. Proc Natl Acad Sci U S A 2020; 117:12836-12846. [PMID: 32457157 PMCID: PMC7293644 DOI: 10.1073/pnas.2004317117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The development of methyl-transverse relaxation-optimized spectroscopy (methyl-TROSY)-based NMR methods, in concert with robust strategies for incorporation of methyl-group probes of structure and dynamics into the protein of interest, has facilitated quantitative studies of high-molecular-weight protein complexes. Here we develop a one-pot in vitro reaction for producing NMR quantities of methyl-labeled DNA at the C5 and N6 positions of cytosine (5mC) and adenine (6mA) nucleobases, respectively, enabling the study of high-molecular-weight DNA molecules using TROSY approaches originally developed for protein applications. Our biosynthetic strategy exploits the large number of naturally available methyltransferases to specifically methylate DNA at a desired number of sites that serve as probes of structure and dynamics. We illustrate the methodology with studies of the 153-base pair Widom DNA molecule that is simultaneously methyl-labeled at five sites, showing that high-quality 13C-1H spectra can be recorded on 100 μM samples in a few minutes. NMR spin relaxation studies of labeled methyl groups in both DNA and the H2B histone protein component of the 200-kDa nucleosome core particle (NCP) establish that methyl groups at 5mC and 6mA positions are, in general, more rigid than Ile, Leu, and Val methyl probes in protein side chains. Studies focusing on histone H2B of NCPs wrapped with either wild-type DNA or DNA methylated at all 26 CpG sites highlight the utility of NMR in investigating the structural dynamics of the NCP and how its histone core is affected through DNA methylation, an important regulator of transcription.
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Affiliation(s)
- Gili Abramov
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Algirdas Velyvis
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Bioscience Department, Syngenta, Jealott's Hill Research Centre, Bracknell RG42 6EY, United Kingdom
| | - Enrico Rennella
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Leo E Wong
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Lewis E Kay
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada;
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
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16
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Delhommel F, Gabel F, Sattler M. Current approaches for integrating solution NMR spectroscopy and small-angle scattering to study the structure and dynamics of biomolecular complexes. J Mol Biol 2020; 432:2890-2912. [DOI: 10.1016/j.jmb.2020.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/27/2020] [Accepted: 03/10/2020] [Indexed: 01/24/2023]
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17
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Schütz S, Sprangers R. Methyl TROSY spectroscopy: A versatile NMR approach to study challenging biological systems. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 116:56-84. [PMID: 32130959 DOI: 10.1016/j.pnmrs.2019.09.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/09/2019] [Accepted: 09/25/2019] [Indexed: 05/21/2023]
Abstract
A major goal in structural biology is to unravel how molecular machines function in detail. To that end, solution-state NMR spectroscopy is ideally suited as it is able to study biological assemblies in a near natural environment. Based on methyl TROSY methods, it is now possible to record high-quality data on complexes that are far over 100 kDa in molecular weight. In this review, we discuss the theoretical background of methyl TROSY spectroscopy, the information that can be extracted from methyl TROSY spectra and approaches that can be used to assign methyl resonances in large complexes. In addition, we touch upon insights that have been obtained for a number of challenging biological systems, including the 20S proteasome, the RNA exosome, molecular chaperones and G-protein-coupled receptors. We anticipate that methyl TROSY methods will be increasingly important in modern structural biology approaches, where information regarding static structures is complemented with insights into conformational changes and dynamic intermolecular interactions.
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Affiliation(s)
- Stefan Schütz
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Remco Sprangers
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany.
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18
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A 300-fold enhancement of imino nucleic acid resonances by hyperpolarized water provides a new window for probing RNA refolding by 1D and 2D NMR. Proc Natl Acad Sci U S A 2020; 117:2449-2455. [PMID: 31949004 DOI: 10.1073/pnas.1916956117] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
NMR sensitivity-enhancement methods involving hyperpolarized water could be of importance for solution-state biophysical investigations. Hyperpolarized water (HyperW) can enhance the 1H NMR signals of exchangeable sites by orders of magnitude over their thermal counterparts, while providing insight into chemical exchange and solvent accessibility at a site-resolved level. As HyperW's enhancements are achieved by exploiting fast solvent exchanges associated with minimal interscan delays, possibilities for the rapid monitoring of chemical reactions and biomolecular (re)folding are opened. HyperW NMR can also accommodate heteronuclear transfers, facilitating the rapid acquisition of 2-dimensional (2D) 15N-1H NMR correlations, and thereby combining an enhanced spectral resolution with speed and sensitivity. This work demonstrates how these qualities can come together for the study of nucleic acids. HyperW injections were used to target the guanine-sensing riboswitch aptamer domain (GSRapt) of the xpt-pbuX operon in Bacillus subtilis Unlike what had been observed in proteins, where residues benefited of HyperW NMR only if/when sufficiently exposed to water, these enhancements applied to every imino resonance throughout the RNA. The >300-fold enhancements observed in the resulting 1H NMR spectra allowed us to monitor in real time the changes that GSRapt undergoes upon binding hypoxanthine, a high-affinity interaction leading to conformational refolding on a ∼1-s timescale at 36 °C. Structural responses could be identified for several nucleotides by 1-dimensional (1D) imino 1H NMR as well as by 2D HyperW NMR spectra acquired upon simultaneous injection of hyperpolarized water and hypoxanthine. The folding landscape revealed by this HyperW strategy for GSRapt, is briefly discussed.
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19
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Shi H, Liu B, Nussbaumer F, Rangadurai A, Kreutz C, Al-Hashimi HM. NMR Chemical Exchange Measurements Reveal That N6-Methyladenosine Slows RNA Annealing. J Am Chem Soc 2019; 141:19988-19993. [PMID: 31826614 DOI: 10.1021/jacs.9b10939] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
N6-Methyladenosine (m6A) is an abundant epitranscriptomic modification that plays important roles in many aspects of RNA metabolism. While m6A is thought to mainly function by recruiting reader proteins to specific RNA sites, the modification can also reshape RNA-protein and RNA-RNA interactions by altering RNA structure mainly by destabilizing base pairing. Little is known about how m6A and other epitranscriptomic modifications might affect the kinetic rates of RNA folding and other conformational transitions that are also important for cellular activity. Here, we used NMR R1ρ relaxation dispersion and chemical exchange saturation transfer to noninvasively and site-specifically measure nucleic acid hybridization kinetics. The methodology was validated on two DNA duplexes and then applied to examine how a single m6A alters the hybridization kinetics in two RNA duplexes. The results show that m6A minimally impacts the rate constant for duplex dissociation, changing koff by ∼1-fold but significantly slows the rate of duplex annealing, decreasing kon by ∼7-fold. A reduction in the annealing rate was observed robustly for two different sequence contexts at different temperatures, both in the presence and absence of Mg2+. We propose that rotation of the N6-methyl group from the preferred syn conformation in the unpaired nucleotide to the energetically disfavored anti conformation required for Watson-Crick pairing is responsible for the reduced annealing rate. The results help explain why in mRNA m6A slows down tRNA selection and more generally suggest that m6A may exert cellular functions by reshaping the kinetics of RNA conformational transitions.
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Affiliation(s)
- Honglue Shi
- Department of Chemistry , Duke University , Durham , North Carolina 27710 , United States
| | - Bei Liu
- Department of Biochemistry , Duke University School of Medicine , Durham , North Carolina 27710 , United States
| | - Felix Nussbaumer
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI) , University of Innsbruck , 6020 Innsbruck , Austria
| | - Atul Rangadurai
- Department of Biochemistry , Duke University School of Medicine , Durham , North Carolina 27710 , United States
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI) , University of Innsbruck , 6020 Innsbruck , Austria
| | - Hashim M Al-Hashimi
- Department of Chemistry , Duke University , Durham , North Carolina 27710 , United States.,Department of Biochemistry , Duke University School of Medicine , Durham , North Carolina 27710 , United States
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20
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Yuwen T, Kay LE. Revisiting 1H N CPMG relaxation dispersion experiments: a simple modification can eliminate large artifacts. JOURNAL OF BIOMOLECULAR NMR 2019; 73:641-650. [PMID: 31646421 DOI: 10.1007/s10858-019-00276-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 09/06/2019] [Indexed: 05/25/2023]
Abstract
Carr-Purcell-Meiboom-Gill relaxation dispersion experiments are commonly used to probe biomolecular dynamics on the millisecond timescale. The simplest experiment involves using backbone 15N spins as probes of motion and pulse sequences are now available for providing accurate dispersion profiles in this case. In contrast, 1H-based experiments recorded on fully protonated samples are less common because of difficulties associated with homonuclear scalar couplings that can result in transfer of magnetization between coupled spins, leading to significant artifacts. Herein we examine a version of the 1HN CPMG experiment that has been used in our laboratory where a pair of CPMG pulse trains comprising non-selective, high power 1H refocusing pulses sandwich an amide selective pulse that serves to refocus scalar-coupled evolution by the end of the train. The origin of the artifacts in our original scheme is explained and a new, significantly improved sequence is presented. The utility of the new experiment is demonstrated by obtaining flat 1HN dispersion profiles in a protonated protein system that is not expected to undergo millisecond timescale dynamics, and subsequently by measuring profiles on a cavity mutant of T4 lysozyme that exchanges between a pair of distinct states, establishing that high quality data can be generated even for fully protonated samples.
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Affiliation(s)
- Tairan Yuwen
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Lewis E Kay
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Program in Molecular Medicine, Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada.
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21
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Bibow S. Opportunities and Challenges of Backbone, Sidechain, and RDC Experiments to Study Membrane Protein Dynamics in a Detergent-Free Lipid Environment Using Solution State NMR. Front Mol Biosci 2019; 6:103. [PMID: 31709261 PMCID: PMC6823230 DOI: 10.3389/fmolb.2019.00103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 09/19/2019] [Indexed: 12/22/2022] Open
Abstract
Whereas solution state NMR provided a wealth of information on the dynamics landscape of soluble proteins, only few studies have investigated membrane protein dynamics in a detergent-free lipid environment. Recent developments of smaller nanodiscs and other lipid-scaffolding polymers, such as styrene maleic acid (SMA), however, open new and promising avenues to explore the function-dynamics relationship of membrane proteins as well as between membrane proteins and their surrounding lipid environment. Favorably sized lipid-bilayer nanodiscs, established membrane protein reconstitution protocols and sophisticated solution NMR relaxation methods probing dynamics over a wide range of timescales will eventually reveal unprecedented lipid-membrane protein interdependencies that allow us to explain things we have not been able to explain so far. In particular, methyl group dynamics resulting from CEST, CPMG, ZZ exchange, and RDC experiments are expected to provide new and surprising insights due to their proximity to lipids, their applicability in large 100+ kDa assemblies and their simple labeling due to the availability of commercial precursors. This review summarizes the recent developments of membrane protein dynamics with a special focus on membrane protein dynamics in lipid-bilayer nanodiscs. Opportunities and challenges of backbone, side chain and RDC dynamics applied to membrane proteins are discussed. Solution-state NMR and lipid nanodiscs bear great potential to change our molecular understanding of lipid-membrane protein interactions.
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Affiliation(s)
- Stefan Bibow
- Biozentrum, University of Basel, Basel, Switzerland
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22
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Gorman SD, Boehr DD. Energy and Enzyme Activity Landscapes of Yeast Chorismate Mutase at Cellular Concentrations of Allosteric Effectors. Biochemistry 2019; 58:4058-4069. [DOI: 10.1021/acs.biochem.9b00721] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Scott D. Gorman
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - David D. Boehr
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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23
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Toyama Y, Shimada I. Frequency selective coherence transfer NMR spectroscopy to study the structural dynamics of high molecular weight proteins. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 304:62-77. [PMID: 31129430 DOI: 10.1016/j.jmr.2019.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/05/2019] [Accepted: 05/14/2019] [Indexed: 06/09/2023]
Abstract
Multidimensional nuclear magnetic resonance (NMR) spectroscopy has enabled detailed characterizations of protein structures and dynamics that are closely linked to functions. However, it leads to a large sensitivity loss in applications to high molecular weight proteins, which is caused by spin relaxation during the frequency discrimination period in the indirect dimension. Here, we describe a selective coherence transfer scheme, which enables us to selectively observe 1H nuclei bonded to 15N or 13C nuclei with specified resonance frequencies. By utilizing this scheme, we achieved a 2.5- to 6-fold increase in signal height per unit of time with this scheme by avoiding the relaxation loss in the indirect dimension, as compared to the conventional two-dimensional heteronuclear correlation spectroscopy. We also demonstrated the effectiveness of this approach with applications to the membrane protein KirBac1.1, and characterized the functionally relevant conformational exchange process in both detergent micelles and a reconstituted membrane environment, corresponding to the apparent molecular masses of 220 kDa and 300 kDa, respectively.
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Affiliation(s)
- Yuki Toyama
- 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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24
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Rangadurai A, Szymaski ES, Kimsey IJ, Shi H, Al-Hashimi HM. Characterizing micro-to-millisecond chemical exchange in nucleic acids using off-resonance R 1ρ relaxation dispersion. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 112-113:55-102. [PMID: 31481159 PMCID: PMC6727989 DOI: 10.1016/j.pnmrs.2019.05.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 05/09/2019] [Accepted: 05/10/2019] [Indexed: 05/10/2023]
Abstract
This review describes off-resonance R1ρ relaxation dispersion NMR methods for characterizing microsecond-to-millisecond chemical exchange in uniformly 13C/15N labeled nucleic acids in solution. The review opens with a historical account of key developments that formed the basis for modern R1ρ techniques used to study chemical exchange in biomolecules. A vector model is then used to describe the R1ρ relaxation dispersion experiment, and how the exchange contribution to relaxation varies with the amplitude and frequency offset of an applied spin-locking field, as well as the population, exchange rate, and differences in chemical shifts of two exchanging species. Mathematical treatment of chemical exchange based on the Bloch-McConnell equations is then presented and used to examine relaxation dispersion profiles for more complex exchange scenarios including three-state exchange. Pulse sequences that employ selective Hartmann-Hahn cross-polarization transfers to excite individual 13C or 15N spins are then described for measuring off-resonance R1ρ(13C) and R1ρ(15N) in uniformly 13C/15N labeled DNA and RNA samples prepared using commercially available 13C/15N labeled nucleotide triphosphates. Approaches for analyzing R1ρ data measured at a single static magnetic field to extract a full set of exchange parameters are then presented that rely on numerical integration of the Bloch-McConnell equations or the use of algebraic expressions. Methods for determining structures of nucleic acid excited states are then reviewed that rely on mutations and chemical modifications to bias conformational equilibria, as well as structure-based approaches to calculate chemical shifts. Applications of the methodology to the study of DNA and RNA conformational dynamics are reviewed and the biological significance of the exchange processes is briefly discussed.
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Affiliation(s)
- Atul Rangadurai
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Eric S Szymaski
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Isaac J Kimsey
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA; Nymirum, 4324 S. Alston Avenue, Durham, NC 27713, USA(1)
| | - Honglue Shi
- Department of Chemistry, Duke University, Durham, NC 27710, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA; Department of Chemistry, Duke University, Durham, NC 27710, USA.
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25
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Walinda E, Morimoto D, Sugase K. Overview of Relaxation Dispersion NMR Spectroscopy to Study Protein Dynamics and Protein-Ligand Interactions. ACTA ACUST UNITED AC 2019; 92:e57. [PMID: 30040207 DOI: 10.1002/cpps.57] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Proteins and nucleic acids are central to all biological processes. NMR spectroscopy has proven to be excellent for studying the dynamics of these macromolecules over various timescales. Relaxation rates and heteronuclear nuclear Overhauser-effect values can resolve motion on pico- to nanosecond timescales, residual dipolar couplings provide information on submicro- to millisecond timescales, and even slower dynamics over seconds to hours can be resolved by hydrogen-exchange experiments. Relaxation dispersion experiments are especially valuable because they resolve motion on micro- to millisecond timescales, encompassing biomolecular motions associated with ligand binding, enzymatic catalysis, and domain-domain opening. These experiments provide structural, kinetic, and thermodynamic information on "invisible" excited conformational states. Relaxation dispersion can be applied not only to single biomolecules but also to protein-ligand complexes to study the kinetics and thermodynamics of association and dissociation. We review recent developments in relaxation dispersion methodology, outline the R1ρ relaxation dispersion experiment, and discuss application to biomolecular interactions. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Erik Walinda
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Kyoto University, Yoshida Konoe-cho, Sakyo-Ku, Kyoto, Japan
| | - Daichi Morimoto
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura, Nishikyo-Ku, Kyoto, Japan
| | - Kenji Sugase
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura, Nishikyo-Ku, Kyoto, Japan
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26
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Abstract
GEST NMR provides dynamic information on host–guest systems. It allows signal amplification of low concentrated complexes, detection of intermolecular interactions and quantification of guest exchange rates.
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Affiliation(s)
- Liat Avram
- Faculty of Chemistry
- Weizmann Institute of Science
- 7610001 Rehovot
- Israel
| | - Amnon Bar-Shir
- Faculty of Chemistry
- Weizmann Institute of Science
- 7610001 Rehovot
- Israel
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27
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Proudfoot A, Frank AO, Frommlet A, Lingel A. Selective Methyl Labeling of Proteins: Enabling Structural and Mechanistic Studies As Well As Drug Discovery Applications by Solution-State NMR. Methods Enzymol 2018; 614:1-36. [PMID: 30611421 DOI: 10.1016/bs.mie.2018.08.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Escherichia coli expression protocols for selective labeling of methyl groups in proteins have been essential in expanding the size range of targets that can be studied by biomolecular NMR. Based on the initial work achieving selective labeling of isoleucine, leucine, and valine residues, additional methods were developed over the past years which enabled the individual and/or simultaneous combinatorial labeling of all methyl containing amino acids. Together with the introduction of new methyl-optimized NMR experiments, this now allows the detailed characterization of protein-ligand interactions as well as mechanistic and dynamic processes of protein-protein complexes up to 1MDa in size. In this chapter, we provide a general introduction to selective labeling of proteins using E. coli-based expression systems, describe the considerations taken into account prior to the selective labeling of a protein, and include the protocols used to produce such proteins. An overview of applications using selectively labeled proteins with an emphasis on examples relevant to the drug discovery process is then presented.
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Affiliation(s)
- Andrew Proudfoot
- Structural and Biophysical Chemistry, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, CA, United States
| | - Andreas O Frank
- Structural and Biophysical Chemistry, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, CA, United States
| | - Alexandra Frommlet
- Structural and Biophysical Chemistry, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, CA, United States
| | - Andreas Lingel
- Structural and Biophysical Chemistry, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, CA, United States; Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Novartis Campus, Basel, Switzerland.
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28
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Boswell ZK, Latham MP. Methyl-Based NMR Spectroscopy Methods for Uncovering Structural Dynamics in Large Proteins and Protein Complexes. Biochemistry 2018; 58:144-155. [PMID: 30336000 DOI: 10.1021/acs.biochem.8b00953] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
NMR spectroscopy is particularly adept at site-specifically monitoring dynamic processes in proteins, such as protein folding, domain movements, ligand binding, and side-chain rotations. By coupling the favorable spectroscopic properties of highly dynamic side-chain methyl groups with transverse-relaxation-optimized spectroscopy (TROSY), it is now possible to routinely study such dynamic processes in high-molecular-weight proteins and complexes approaching 1 MDa. In this Perspective, we describe many elegant methyl-based NMR experiments that probe slow (second) to fast (picosecond) dynamics in large systems. To demonstrate the power of these methods, we also provide interesting examples of studies that utilized each methyl-based NMR technique to uncover functionally important dynamics. In many cases, the NMR experiments are paired with site-directed mutagenesis and/or other biochemical assays to put the dynamics and function into context. Our vision of the future of structural biology involves pairing methyl-based NMR spectroscopy with biochemical studies to advance our knowledge of the motions large proteins and macromolecular complexes use to choreograph complex functions. Such studies will be essential in elucidating the critical structural dynamics that underlie function and characterizing alterations in these processes that can lead to human disease.
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Affiliation(s)
- Zachary K Boswell
- Department of Chemistry and Biochemistry , Texas Tech University , Lubbock , Texas 79423 , United States
| | - Michael P Latham
- Department of Chemistry and Biochemistry , Texas Tech University , Lubbock , Texas 79423 , United States
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29
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Månsson C, van Cruchten RTP, Weininger U, Yang X, Cukalevski R, Arosio P, Dobson CM, Knowles T, Akke M, Linse S, Emanuelsson C. Conserved S/T Residues of the Human Chaperone DNAJB6 Are Required for Effective Inhibition of Aβ42 Amyloid Fibril Formation. Biochemistry 2018; 57:4891-4902. [DOI: 10.1021/acs.biochem.8b00353] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Cecilia Månsson
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, 221 00 Lund, Sweden
| | - Remco T. P. van Cruchten
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, 221 00 Lund, Sweden
| | - Ulrich Weininger
- Department of Biophysical Chemistry, Center for Molecular Protein Science, Lund University, 221 00 Lund, Sweden
| | - Xiaoting Yang
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, 221 00 Lund, Sweden
| | - Risto Cukalevski
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, 221 00 Lund, Sweden
| | - Paolo Arosio
- Department of Chemistry and Center for Misfolding Diseases, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Christopher M. Dobson
- Department of Chemistry and Center for Misfolding Diseases, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Tuomas Knowles
- Department of Chemistry and Center for Misfolding Diseases, University of Cambridge, Cambridge CB2 1EW, U.K
- Cavendish Laboratory, Department of Physics, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Mikael Akke
- Department of Biophysical Chemistry, Center for Molecular Protein Science, Lund University, 221 00 Lund, Sweden
| | - Sara Linse
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, 221 00 Lund, Sweden
| | - Cecilia Emanuelsson
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, 221 00 Lund, Sweden
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30
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Yuwen T, Bouvignies G, Kay LE. Exploring methods to expedite the recording of CEST datasets using selective pulse excitation. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 292:1-7. [PMID: 29753980 DOI: 10.1016/j.jmr.2018.04.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 04/23/2018] [Accepted: 04/24/2018] [Indexed: 06/08/2023]
Abstract
Chemical Exchange Saturation Transfer (CEST) has emerged as a powerful tool for studies of biomolecular conformational exchange involving the interconversion between a major, visible conformer and one or more minor, invisible states. Applications typically entail recording a large number of 2D datasets, each of which differs in the position of a weak radio frequency field, so as to generate a CEST profile for each nucleus from which the chemical shifts of spins in the invisible state(s) are obtained. Here we compare a number of band-selective CEST schemes for speeding up the process using either DANTE or cosine-modulated excitation approaches. We show that while both are essentially identical for applications such as 15N CEST, in cases where the probed spins are dipolar or scalar coupled to other like spins there can be advantages for the cosine-excitation scheme.
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Affiliation(s)
- Tairan Yuwen
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
| | - Guillaume Bouvignies
- Laboratoire des biomolécules, LBM, Département de chimie, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
| | - Lewis E Kay
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Hospital for Sick Children, Program in Molecular Medicine, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada.
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31
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Gorman SD, Sahu D, O'Rourke KF, Boehr DD. Assigning methyl resonances for protein solution-state NMR studies. Methods 2018; 148:88-99. [PMID: 29958930 DOI: 10.1016/j.ymeth.2018.06.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 06/16/2018] [Accepted: 06/18/2018] [Indexed: 10/28/2022] Open
Abstract
Solution-state NMR is an important tool for studying protein structure and function. The ability to probe methyl groups has substantially expanded the scope of proteins accessible by NMR spectroscopy, including facilitating study of proteins and complexes greater than 100 kDa in size. While the toolset for studying protein structure and dynamics by NMR continues to grow, a major rate-limiting step in these studies is the initial resonance assignments, especially for larger (>50 kDa) proteins. In this practical review, we present strategies to efficiently isotopically label proteins, delineate NMR pulse sequences that can be used to determine methyl resonance assignments in the presence and absence of backbone assignments, and outline computational methods for NMR data analysis. We use our experiences from assigning methyl resonances for the aromatic biosynthetic enzymes tryptophan synthase and chorismate mutase to provide advice for all stages of experimental set-up and data analysis.
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Affiliation(s)
- Scott D Gorman
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Debashish Sahu
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Kathleen F O'Rourke
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - David D Boehr
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA.
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32
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Leninger M, Marsiglia WM, Jerschow A, Traaseth NJ. Multiple frequency saturation pulses reduce CEST acquisition time for quantifying conformational exchange in biomolecules. JOURNAL OF BIOMOLECULAR NMR 2018; 71:19-30. [PMID: 29796789 PMCID: PMC5989009 DOI: 10.1007/s10858-018-0186-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 05/11/2018] [Indexed: 05/03/2023]
Abstract
Exchange between conformational states is required for biomolecular catalysis, allostery, and folding. A variety of NMR experiments have been developed to quantify motional regimes ranging from nanoseconds to seconds. In this work, we describe an approach to speed up the acquisition of chemical exchange saturation transfer (CEST) experiments that are commonly used to probe millisecond to second conformational exchange in proteins and nucleic acids. The standard approach is to obtain CEST datasets through the acquisition of a series of 2D correlation spectra where each experiment utilizes a single saturation frequency to 1H, 15N or 13C. These pseudo 3D datasets are time consuming to collect and are further lengthened by reduced signal to noise stemming from the long saturation pulse. In this article, we show how usage of a multiple frequency saturation pulse (i.e., MF-CEST) changes the nature of data collection from series to parallel, and thus decreases the total acquisition time by an integer factor corresponding to the number of frequencies in the pulse. We demonstrate the applicability of MF-CEST on a Src homology 2 (SH2) domain from phospholipase Cγ and the secondary active transport protein EmrE as model systems by collecting 13C methyl and 15N backbone datasets. MF-CEST can also be extended to additional sites within proteins and nucleic acids. The only notable drawback of MF-CEST as applied to backbone 15N experiments occurs when a large chemical shift difference between the major and minor populations is present (typically greater than ~ 8 ppm). In these cases, ambiguity may arise between the chemical shift of the minor population and the multiple frequency saturation pulse. Nevertheless, this drawback does not occur for methyl group MF-CEST experiments or in cases where somewhat smaller chemical shift differences occur are present.
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Affiliation(s)
- Maureen Leninger
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY, 10003, USA
| | - William M Marsiglia
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY, 10003, USA
| | - Alexej Jerschow
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY, 10003, USA
| | - Nathaniel J Traaseth
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY, 10003, USA.
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33
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Shi H, Clay MC, Rangadurai A, Sathyamoorthy B, Case DA, Al-Hashimi HM. Atomic structures of excited state A-T Hoogsteen base pairs in duplex DNA by combining NMR relaxation dispersion, mutagenesis, and chemical shift calculations. JOURNAL OF BIOMOLECULAR NMR 2018; 70:229-244. [PMID: 29675775 PMCID: PMC6048961 DOI: 10.1007/s10858-018-0177-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 03/29/2018] [Indexed: 05/20/2023]
Abstract
NMR relaxation dispersion studies indicate that in canonical duplex DNA, Watson-Crick base pairs (bps) exist in dynamic equilibrium with short-lived low abundance excited state Hoogsteen bps. N1-methylated adenine (m1A) and guanine (m1G) are naturally occurring forms of damage that stabilize Hoogsteen bps in duplex DNA. NMR dynamic ensembles of DNA duplexes with m1A-T Hoogsteen bps reveal significant changes in sugar pucker and backbone angles in and around the Hoogsteen bp, as well as kinking of the duplex towards the major groove. Whether these structural changes also occur upon forming excited state Hoogsteen bps in unmodified duplexes remains to be established because prior relaxation dispersion probes provided limited information regarding the sugar-backbone conformation. Here, we demonstrate measurements of C3' and C4' spin relaxation in the rotating frame (R1ρ) in uniformly 13C/15N labeled DNA as sensitive probes of the sugar-backbone conformation in DNA excited states. The chemical shifts, combined with structure-based predictions using an automated fragmentation quantum mechanics/molecular mechanics method, show that the dynamic ensemble of DNA duplexes containing m1A-T Hoogsteen bps accurately model the excited state Hoogsteen conformation in two different sequence contexts. Formation of excited state A-T Hoogsteen bps is accompanied by changes in sugar-backbone conformation that allow the flipped syn adenine to form hydrogen-bonds with its partner thymine and this in turn results in overall kinking of the DNA toward the major groove. Results support the assignment of Hoogsteen bps as the excited state observed in canonical duplex DNA, provide an atomic view of DNA dynamics linked to formation of Hoogsteen bps, and lay the groundwork for a potentially general strategy for solving structures of nucleic acid excited states.
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Affiliation(s)
- Honglue Shi
- Department of Chemistry, Duke University, Durham, NC 27710, USA
| | - Mary C. Clay
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Atul Rangadurai
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Bharathwaj Sathyamoorthy
- Department of Chemistry, Duke University, Durham, NC 27710, USA
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - David A. Case
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
- To whom correspondence should be addressed. Telephone: (919) 660-1113, or
| | - Hashim M. Al-Hashimi
- Department of Chemistry, Duke University, Durham, NC 27710, USA
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- To whom correspondence should be addressed. Telephone: (919) 660-1113, or
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34
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Wu Q, Fenton BA, Wojtaszek JL, Zhou P. Probing the excited-state chemical shifts and exchange parameters by nitrogen-decoupled amide proton chemical exchange saturation transfer (HN dec-CEST). Chem Commun (Camb) 2018; 53:8541-8544. [PMID: 28707688 DOI: 10.1039/c7cc05021f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
CEST-NMR spectroscopy is a powerful tool for probing the conformational dynamics of macromolecules. We present a HNdec-CEST experiment that simplifies the relaxation matrix, reduces fitting parameters, and enhances signal resolution. Importantly, fitting of HNdec-CEST profiles enables robust extraction of exchange rates as well as excited-state chemical shifts and populations.
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Affiliation(s)
- Qinglin Wu
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
| | - Benjamin A Fenton
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
| | - Jessica L Wojtaszek
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
| | - Pei Zhou
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
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35
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Yuwen T, Kay LE. A new class of CEST experiment based on selecting different magnetization components at the start and end of the CEST relaxation element: an application to 1H CEST. JOURNAL OF BIOMOLECULAR NMR 2018; 70:93-102. [PMID: 29352366 DOI: 10.1007/s10858-017-0161-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 12/22/2017] [Indexed: 06/07/2023]
Abstract
Chemical exchange saturation transfer (CEST) experiments are becoming increasingly popular for investigating biomolecular exchange dynamics with rates on the order of approximately 50-500 s-1 and a rich toolkit of different methods has emerged over the past few years. Typically, experiments are based on the evolution of longitudinal magnetization, or in some cases two-spin order, during a fixed CEST relaxation delay, with the same class of magnetization prepared at the start and selected at end of the CEST period. Here we present a pair of TROSY-based pulse schemes for recording amide and methyl 1H CEST profiles where longitudinal magnetization at the start evolves to produce two-spin order that is then selected at the completion of the CEST element. This selection process subtracts out contributions from 1H-1H cross-relaxation on the fly that would otherwise complicate analysis of the data. It also obviates the need to record spin-state selective CEST profiles as an alternative to eliminating NOE effects, leading to significant improvements in sensitivity. The utility of the approach is demonstrated on a sample of a cavity mutant of T4 lysozyme that undergoes chemical exchange between conformations where the cavity is free and occupied.
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Affiliation(s)
- Tairan Yuwen
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Lewis E Kay
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON, M5G 0A4, Canada.
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36
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Yuwen T, Brady JP, Kay LE. Probing Conformational Exchange in Weakly Interacting, Slowly Exchanging Protein Systems via Off-Resonance R1ρ Experiments: Application to Studies of Protein Phase Separation. J Am Chem Soc 2018; 140:2115-2126. [DOI: 10.1021/jacs.7b09576] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Tairan Yuwen
- Departments
of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Jacob P. Brady
- Departments
of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Lewis E. Kay
- Departments
of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8
- Hospital for Sick Children, Program in Molecular Medicine, Toronto, Ontario, Canada M5G 1X8
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37
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Binding kinetics and substrate selectivity in HIV-1 protease-Gag interactions probed at atomic resolution by chemical exchange NMR. Proc Natl Acad Sci U S A 2017; 114:E9855-E9862. [PMID: 29087351 DOI: 10.1073/pnas.1716098114] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The conversion of immature noninfectious HIV-1 particles to infectious virions is dependent upon the sequential cleavage of the precursor group-specific antigen (Gag) polyprotein by HIV-1 protease. The precise mechanism whereby protease recognizes distinct Gag cleavage sites, located in the intrinsically disordered linkers connecting the globular domains of Gag, remains unclear. Here, we probe the dynamics of the interaction of large fragments of Gag and various variants of protease (including a drug resistant construct) using Carr-Purcell-Meiboom-Gill relaxation dispersion and chemical exchange saturation transfer NMR experiments. We show that the conformational dynamics within the flaps of HIV-1 protease that form the lid over the catalytic cleft play a significant role in substrate specificity and ordered Gag processing. Rapid interconversion between closed and open protease flap conformations facilitates the formation of a transient, sparsely populated productive complex between protease and Gag substrates. Flap closure traps the Gag cleavage sites within the catalytic cleft of protease. Modulation of flap opening through protease-Gag interactions fine-tunes the lifetime of the productive complex and hence the likelihood of Gag proteolysis. A productive complex can also be formed in the presence of a noncognate substrate but is short-lived owing to lack of optimal complementarity between the active site cleft of protease and the substrate, resulting in rapid flap opening and substrate release, thereby allowing protease to differentiate between cognate and noncognate substrates.
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38
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Huang R, Brady JP, Sekhar A, Yuwen T, Kay LE. An enhanced sensitivity methyl 1H triple-quantum pulse scheme for measuring diffusion constants of macromolecules. JOURNAL OF BIOMOLECULAR NMR 2017; 68:249-255. [PMID: 28717997 DOI: 10.1007/s10858-017-0122-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/21/2017] [Indexed: 06/07/2023]
Abstract
We present a pulse scheme that exploits methyl 1H triple-quantum (TQ) coherences for the measurement of diffusion rates of slowly diffusing molecules in solution. It is based on the well-known stimulated echo experiment, with encoding and decoding of TQ coherences. The size of quantifiable diffusion coefficients is thus lowered by an order of magnitude with respect to single-quantum (SQ) approaches. Notably, the sensitivity of the scheme is high, approximately ¾ that of the corresponding single quantum experiment, neglecting relaxation losses, and on the order of a factor of 4 more sensitive than a previously published sequence for AX3 spin systems (Zheng et al. in JMR 198:271-274, 2009) for molecules that are only 13C labeled at the methyl carbon position. Diffusion coefficients measured from TQ- and SQ-based experiments recorded on a range of protein samples are in excellent agreement. We present an application of this technique to the study of phase-separated proteins where protein concentrations in the condensed phase can exceed 400 mg/mL, diffusion coefficients can be as low as ~10-9 cm2s-1 and traditional SQ experiments fail.
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Affiliation(s)
- Rui Huang
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Jacob P Brady
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Ashok Sekhar
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Tairan Yuwen
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Lewis E Kay
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- The Hospital for Sick Children Research Institute, Toronto, ON, M5G 0A4, Canada.
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39
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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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40
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Zhuravleva A, Korzhnev DM. Protein folding by NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2017; 100:52-77. [PMID: 28552172 DOI: 10.1016/j.pnmrs.2016.10.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 10/17/2016] [Accepted: 10/17/2016] [Indexed: 06/07/2023]
Abstract
Protein folding is a highly complex process proceeding through a number of disordered and partially folded nonnative states with various degrees of structural organization. These transiently and sparsely populated species on the protein folding energy landscape play crucial roles in driving folding toward the native conformation, yet some of these nonnative states may also serve as precursors for protein misfolding and aggregation associated with a range of devastating diseases, including neuro-degeneration, diabetes and cancer. Therefore, in vivo protein folding is often reshaped co- and post-translationally through interactions with the ribosome, molecular chaperones and/or other cellular components. Owing to developments in instrumentation and methodology, solution NMR spectroscopy has emerged as the central experimental approach for the detailed characterization of the complex protein folding processes in vitro and in vivo. NMR relaxation dispersion and saturation transfer methods provide the means for a detailed characterization of protein folding kinetics and thermodynamics under native-like conditions, as well as modeling high-resolution structures of weakly populated short-lived conformational states on the protein folding energy landscape. Continuing development of isotope labeling strategies and NMR methods to probe high molecular weight protein assemblies, along with advances of in-cell NMR, have recently allowed protein folding to be studied in the context of ribosome-nascent chain complexes and molecular chaperones, and even inside living cells. Here we review solution NMR approaches to investigate the protein folding energy landscape, and discuss selected applications of NMR methodology to studying protein folding in vitro and in vivo. Together, these examples highlight a vast potential of solution NMR in providing atomistic insights into molecular mechanisms of protein folding and homeostasis in health and disease.
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Affiliation(s)
- Anastasia Zhuravleva
- Astbury Centre for Structural Molecular Biology and Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom.
| | - Dmitry M Korzhnev
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030, USA.
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41
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Yuwen T, Kay LE. Longitudinal relaxation optimized amide 1H-CEST experiments for studying slow chemical exchange processes in fully protonated proteins. JOURNAL OF BIOMOLECULAR NMR 2017; 67:295-307. [PMID: 28357518 DOI: 10.1007/s10858-017-0104-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/06/2017] [Indexed: 06/06/2023]
Abstract
Chemical Exchange Saturation Transfer (CEST) experiments are increasingly used to study slow timescale exchange processes in biomolecules. Although 15N- and 13C-CEST have been the approaches of choice, the development of spin state selective 1H-CEST pulse sequences that separate the effects of chemical and dipolar exchange [T. Yuwen, A. Sekhar and L. E. Kay, Angew Chem Int Ed Engl 2016 doi: 10.1002/anie.201610759 (Yuwen et al. 2017)] significantly increases the utility of 1H-based experiments. Pulse schemes have been described previously for studies of highly deuterated proteins. We present here longitudinal-relaxation optimized amide 1H-CEST experiments for probing chemical exchange in protonated proteins. Applications involving a pair of proteins are presented establishing that accurate 1H chemical shifts of sparsely populated conformers can be obtained from simple analyses of 1H-CEST profiles. A discussion of the inherent differences between 15N-/13C- and 1H-CEST experiments is presented, leading to an optimal strategy for recording 1H-CEST experiments.
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Affiliation(s)
- 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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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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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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Zeng H, Xu J, Yadav NN, McMahon MT, Harden B, Frueh D, van Zijl PCM. (15)N Heteronuclear Chemical Exchange Saturation Transfer MRI. J Am Chem Soc 2016; 138:11136-9. [PMID: 27548755 DOI: 10.1021/jacs.6b06421] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A two-step heteronuclear enhancement approach was combined with chemical exchange saturation transfer (CEST) to magnify (15)N MRI signal of molecules through indirect detection via water protons. Previous CEST studies have been limited to radiofrequency (rf) saturation transfer or excitation transfer employing protons. Here, the signal of (15)N is detected indirectly through the water signal by first inverting selectively protons that are scalar-coupled to (15)N in the urea molecule, followed by chemical exchange of the amide proton to bulk water. In addition to providing a small sensitivity enhancement, this approach can be used to monitor the exchange rates and thus the pH sensitivity of the participating (15)N-bound protons.
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Affiliation(s)
- Haifeng Zeng
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
| | - Jiadi Xu
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
| | - Nirbhay N Yadav
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
| | - Michael T McMahon
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
| | | | | | - Peter C M van Zijl
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
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Furukawa A, Konuma T, Yanaka S, Sugase K. Quantitative analysis of protein-ligand interactions by NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2016; 96:47-57. [PMID: 27573180 DOI: 10.1016/j.pnmrs.2016.02.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 02/21/2016] [Accepted: 02/21/2016] [Indexed: 06/06/2023]
Abstract
Protein-ligand interactions have been commonly studied through static structures of the protein-ligand complex. Recently, however, there has been increasing interest in investigating the dynamics of protein-ligand interactions both for fundamental understanding of the underlying mechanisms and for drug development. NMR is a versatile and powerful tool, especially because it provides site-specific quantitative information. NMR has widely been used to determine the dissociation constant (KD), in particular, for relatively weak interactions. The simplest NMR method is a chemical-shift titration experiment, in which the chemical-shift changes of a protein in response to ligand titration are measured. There are other quantitative NMR methods, but they mostly apply only to interactions in the fast-exchange regime. These methods derive the dissociation constant from population-averaged NMR quantities of the free and bound states of a protein or ligand. In contrast, the recent advent of new relaxation-based experiments, including R2 relaxation dispersion and ZZ-exchange, has enabled us to obtain kinetic information on protein-ligand interactions in the intermediate- and slow-exchange regimes. Based on R2 dispersion or ZZ-exchange, methods that can determine the association rate, kon, dissociation rate, koff, and KD have been developed. In these approaches, R2 dispersion or ZZ-exchange curves are measured for multiple samples with different protein and/or ligand concentration ratios, and the relaxation data are fitted to theoretical kinetic models. It is critical to choose an appropriate kinetic model, such as the two- or three-state exchange model, to derive the correct kinetic information. The R2 dispersion and ZZ-exchange methods are suitable for the analysis of protein-ligand interactions with a micromolar or sub-micromolar dissociation constant but not for very weak interactions, which are typical in very fast exchange. This contrasts with the NMR methods that are used to analyze population-averaged NMR quantities. Essentially, to apply NMR successfully, both the type of experiment and equation to fit the data must be carefully and specifically chosen for the protein-ligand interaction under analysis. In this review, we first explain the exchange regimes and kinetic models of protein-ligand interactions, and then describe the NMR methods that quantitatively analyze these specific interactions.
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Affiliation(s)
- Ayako Furukawa
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 1-1-1 Wakayamadai, Shimamoto, Mishima, Osaka 618-8503, Japan; Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Tsuyoshi Konuma
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 1-1-1 Wakayamadai, Shimamoto, Mishima, Osaka 618-8503, Japan; Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Saeko Yanaka
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 1-1-1 Wakayamadai, Shimamoto, Mishima, Osaka 618-8503, Japan; Department of Life and Coordination-Complex Molecular Science, Biomolecular Functions, Institute of Molecular Science, National Institute of Natural Sciences, Japan
| | - Kenji Sugase
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 1-1-1 Wakayamadai, Shimamoto, Mishima, Osaka 618-8503, Japan; Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura, Nishikyo-Ku, Kyoto 615-8510, Japan.
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Audin MJC, Wurm JP, Cvetkovic MA, Sprangers R. The oligomeric architecture of the archaeal exosome is important for processive and efficient RNA degradation. Nucleic Acids Res 2016; 44:2962-73. [PMID: 26837575 PMCID: PMC4824110 DOI: 10.1093/nar/gkw062] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 01/25/2016] [Indexed: 11/30/2022] Open
Abstract
The exosome plays an important role in RNA degradation and processing. In archaea, three Rrp41:Rrp42 heterodimers assemble into a barrel like structure that contains a narrow RNA entrance pore and a lumen that contains three active sites. Here, we demonstrate that this quaternary structure of the exosome is important for efficient RNA degradation. We find that the entrance pore of the barrel is required for nM substrate affinity. This strong interaction is crucial for processive substrate degradation and prevents premature release of the RNA from the enzyme. Using methyl TROSY NMR techniques, we establish that the 3′ end of the substrate remains highly flexible inside the lumen. As a result, the RNA jumps between the three active sites that all equally participate in substrate degradation. The RNA jumping rate is, however, much faster than the cleavage rate, indicating that not all active site:substrate encounters result in catalysis. Enzymatic turnover therefore benefits from the confinement of the active sites and substrate in the lumen, which ensures that the RNA is at all times bound to one of the active sites. The evolution of the exosome into a hexameric complex and the optimization of its catalytic efficiency were thus likely co-occurring events.
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Affiliation(s)
- Maxime J C Audin
- Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Jan Philip Wurm
- Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Milos A Cvetkovic
- Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Remco Sprangers
- Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
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47
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Gu Y, Hansen AL, Peng Y, Brüschweiler R. Rapid Determination of Fast Protein Dynamics from NMR Chemical Exchange Saturation Transfer Data. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201511711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Yina Gu
- Department of Chemistry and Biochemistry The Ohio State University 100 West 18th Avenue Columbus OH 43210 USA
| | - Alexandar L. Hansen
- Campus Chemical Instrument Center The Ohio State University 460 W. 12th Avenue Columbus OH 43210 USA
| | - Yu Peng
- Department of Chemistry and Biochemistry The Ohio State University 100 West 18th Avenue Columbus OH 43210 USA
| | - Rafael Brüschweiler
- Department of Chemistry and Biochemistry The Ohio State University 100 West 18th Avenue Columbus OH 43210 USA
- Campus Chemical Instrument Center The Ohio State University 460 W. 12th Avenue Columbus OH 43210 USA
- Department of Biological Chemistry and Pharmacology The Ohio State University 1645 Neil Avenue Columbus OH 43210 USA
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48
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Gu Y, Hansen AL, Peng Y, Brüschweiler R. Rapid Determination of Fast Protein Dynamics from NMR Chemical Exchange Saturation Transfer Data. Angew Chem Int Ed Engl 2016; 55:3117-9. [PMID: 26821600 DOI: 10.1002/anie.201511711] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Indexed: 01/03/2023]
Abstract
Functional motions of (15)N-labeled proteins can be monitored by solution NMR spin relaxation experiments over a broad range of timescales. These experiments however typically take of the order of several days to a week per protein. Recently, NMR chemical exchange saturation transfer (CEST) experiments have emerged to probe slow millisecond motions complementing R1ρ and CPMG-type experiments. CEST also simultaneously reports on site-specific R1 and R2 parameters. It is shown here how CEST-derived R1 and R2 relaxation parameters can be measured within a few hours at an accuracy comparable to traditional relaxation experiments. Using a "lean" version of the model-free approach S(2) order parameters can be determined that match those from the standard model-free approach applied to (15)N R1, R2 , and {(1)H}-(15)N NOE data. The new methodology, which is demonstrated for ubiquitin and arginine kinase (42 kDa), should serve as an effective screening tool of protein dynamics from picosecond-to-millisecond timescales.
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Affiliation(s)
- Yina Gu
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA
| | - Alexandar L Hansen
- Campus Chemical Instrument Center, The Ohio State University, 460 W. 12th Avenue, Columbus, OH, 43210, USA
| | - Yu Peng
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA
| | - Rafael Brüschweiler
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA. .,Campus Chemical Instrument Center, The Ohio State University, 460 W. 12th Avenue, Columbus, OH, 43210, USA. .,Department of Biological Chemistry and Pharmacology, The Ohio State University, 1645 Neil Avenue, Columbus, OH, 43210, USA.
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Rennella E, Huang R, Velyvis A, Kay LE. (13)CHD2-CEST NMR spectroscopy provides an avenue for studies of conformational exchange in high molecular weight proteins. JOURNAL OF BIOMOLECULAR NMR 2015; 63:187-99. [PMID: 26271302 DOI: 10.1007/s10858-015-9974-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 07/31/2015] [Indexed: 05/25/2023]
Abstract
An NMR experiment for quantifying slow (millisecond) time-scale exchange processes involving the interconversion between visible ground state and invisible, conformationally excited state conformers is presented. The approach exploits chemical exchange saturation transfer (CEST) and makes use of (13)CHD2 methyl group probes that can be readily incorporated into otherwise highly deuterated proteins. The methodology is validated with an application to a G48A Fyn SH3 domain that exchanges between a folded conformation and a sparsely populated and transiently formed unfolded ensemble. Experiments on a number of different protein systems, including a 360 kDa half-proteasome, establish that the sensitivity of this (13)CHD2 (13)C-CEST technique can be upwards of a factor of 5 times higher than for a previously published (13)CH3 (13)C-CEST approach (Bouvignies and Kay in J Biomol NMR 53:303-310, 2012), suggesting that the methodology will be powerful for studies of conformational exchange in high molecular weight proteins.
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Affiliation(s)
- Enrico Rennella
- Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Rui Huang
- Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Algirdas Velyvis
- Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Lewis E Kay
- Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada.
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50
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Wunderlich CH, Juen MA, LeBlanc RM, Longhini AP, Dayie TK, Kreutz C. Stable isotope-labeled RNA phosphoramidites to facilitate dynamics by NMR. Methods Enzymol 2015; 565:461-94. [PMID: 26577742 DOI: 10.1016/bs.mie.2015.06.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Given that Ribonucleic acids (RNAs) are a central hub of various cellular processes, methods to synthesize these RNAs for biophysical studies are much needed. Here, we showcase the applicability of 6-(13)C-pyrimidine phosphoramidites to introduce isolated (13)C-(1)H spin pairs into RNAs up to 40 nucleotides long. The method allows the incorporation of 6-(13)C-uridine and -cytidine residues at any desired position within a target RNA. By site-specific positioning of the (13)C-label using RNA solid phase synthesis, these stable isotope-labeling patterns are especially well suited to resolve resonance assignment ambiguities. Of even greater importance, the labeling pattern affords accurate quantification of important functional transitions of biologically relevant RNAs (e.g., riboswitch aptamer domains, viral RNAs, or ribozymes) in the μs- to ms time regime and beyond without complications of one bond carbon scalar couplings. We outline the chemical synthesis of the 6-(13)C-pyrimidine building blocks and their use in RNA solid phase synthesis and demonstrate their utility in Carr Purcell Meiboom Gill relaxation dispersion, ZZ exchange, and chemical exchange saturation transfer NMR experiments.
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Affiliation(s)
- Christoph H Wunderlich
- Institute of Organic Chemistry and Center for Biomolecular Sciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Michael A Juen
- Institute of Organic Chemistry and Center for Biomolecular Sciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Regan M LeBlanc
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland, USA
| | - Andrew P Longhini
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland, USA
| | - T Kwaku Dayie
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland, USA.
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Biomolecular Sciences Innsbruck, University of Innsbruck, Innsbruck, Austria.
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