1
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Shukla VK, Heller GT, Hansen DF. Biomolecular NMR spectroscopy in the era of artificial intelligence. Structure 2023; 31:1360-1374. [PMID: 37848030 DOI: 10.1016/j.str.2023.09.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 09/15/2023] [Accepted: 09/21/2023] [Indexed: 10/19/2023]
Abstract
Biomolecular nuclear magnetic resonance (NMR) spectroscopy and artificial intelligence (AI) have a burgeoning synergy. Deep learning-based structural predictors have forever changed structural biology, yet these tools currently face limitations in accurately characterizing protein dynamics, allostery, and conformational heterogeneity. We begin by highlighting the unique abilities of biomolecular NMR spectroscopy to complement AI-based structural predictions toward addressing these knowledge gaps. We then highlight the direct integration of deep learning approaches into biomolecular NMR methods. AI-based tools can dramatically improve the acquisition and analysis of NMR spectra, enhancing the accuracy and reliability of NMR measurements, thus streamlining experimental processes. Additionally, deep learning enables the development of novel types of NMR experiments that were previously unattainable, expanding the scope and potential of biomolecular NMR spectroscopy. Ultimately, a combination of AI and NMR promises to further revolutionize structural biology on several levels, advance our understanding of complex biomolecular systems, and accelerate drug discovery efforts.
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Affiliation(s)
- Vaibhav Kumar Shukla
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK
| | - Gabriella T Heller
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK.
| | - D Flemming Hansen
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK.
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2
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Gaza JT, Nellas RB. Reparameterization of Non-Bonded Parameters for Copper Ions in Plastocyanin: An Adaptive Force Matching Study. J Chem Inf Model 2023; 63:4654-4663. [PMID: 37459569 DOI: 10.1021/acs.jcim.3c00559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Molecular mechanics rely on existing experimental and theoretical inputs to confidently calculate the trajectories of molecular systems. These calculations, however, are often hindered by missing force field parameters. A notable subject of this problem is metal centers of proteins. This study parameterized, through an adaptive force matching (AFM) workflow, the copper cofactor of plastocyanin in its two oxidation states. New 12-6 Lennard-Jones (LJ) parameters and atomic partial charges were generated to complete the non-bonded description of the copper site. Our models show uniform distorted tetrahedral structures for reduced plastocyanin, Cu(I), and oxidized plastocyanin, Cu(II). These structures align with the QM/MM MD results and existing crystallography studies. TD-DFT calculations, meanwhile, showed that conformations with elongated axial Cu-SMet and shortened equatorial Cu-SCys bonds retain the experimental UV-Vis profile of blue copper (BC) proteins, thus signifying the importance of Cu-S interactions on BC proteins' unique spectroscopic properties.
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Affiliation(s)
- Jokent T Gaza
- Institute of Chemistry, College of Science, University of the Philippines Diliman, 1101 Quezon City, Philippines
| | - Ricky B Nellas
- Institute of Chemistry, College of Science, University of the Philippines Diliman, 1101 Quezon City, Philippines
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3
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Trindade IB, Coelho A, Cantini F, Piccioli M, Louro RO. NMR of paramagnetic metalloproteins in solution: Ubi venire, quo vadis? J Inorg Biochem 2022; 234:111871. [DOI: 10.1016/j.jinorgbio.2022.111871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 05/16/2022] [Accepted: 05/19/2022] [Indexed: 10/18/2022]
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4
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Spenner JM, Berg JM. Exploring the use of cobalt(II) dipolar shifts in refining the structure of a zinc finger peptide. J Inorg Biochem 2022; 235:111912. [PMID: 35850025 DOI: 10.1016/j.jinorgbio.2022.111912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 06/13/2022] [Accepted: 07/03/2022] [Indexed: 10/17/2022]
Abstract
The uses of dipolar shifts due to cobalt(II) substituted for zinc(II) in a consensus zinc finger peptide for refining the NMR-determined structure were examined. Substantial differences between the calculated and observed chemical shift differences between the cobalt(II) and zinc(II) complexes were observed when these dipolar shifts were not used as constraints in the structure refinement. However, inclusion of these constraints resulted in excellent agreement with minor adjustments in the structure and a slight improvement in the precision of the structure determination. Other calculations revealed that the dipolar shifts were not adequate to determine the overall folded structure by themselves, but were useful in increasing the accuracy and precision of a structure determined based only on nuclear Overhauser effects constraints involving only backbone atoms.
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Affiliation(s)
- Jonathan M Spenner
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jeremy M Berg
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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5
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Karunanithy G, Yuwen T, Kay LE, Hansen DF. Towards autonomous analysis of chemical exchange saturation transfer experiments using deep neural networks. JOURNAL OF BIOMOLECULAR NMR 2022; 76:75-86. [PMID: 35622310 PMCID: PMC9246985 DOI: 10.1007/s10858-022-00395-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 05/05/2022] [Indexed: 06/12/2023]
Abstract
Macromolecules often exchange between functional states on timescales that can be accessed with NMR spectroscopy and many NMR tools have been developed to characterise the kinetics and thermodynamics of the exchange processes, as well as the structure of the conformers that are involved. However, analysis of the NMR data that report on exchanging macromolecules often hinges on complex least-squares fitting procedures as well as human experience and intuition, which, in some cases, limits the widespread use of the methods. The applications of deep neural networks (DNNs) and artificial intelligence have increased significantly in the sciences, and recently, specifically, within the field of biomolecular NMR, where DNNs are now available for tasks such as the reconstruction of sparsely sampled spectra, peak picking, and virtual decoupling. Here we present a DNN for the analysis of chemical exchange saturation transfer (CEST) data reporting on two- or three-site chemical exchange involving sparse state lifetimes of between approximately 3-60 ms, the range most frequently observed via experiment. The work presented here focuses on the 1H CEST class of methods that are further complicated, in relation to applications to other nuclei, by anti-phase features. The developed DNNs accurately predict the chemical shifts of nuclei in the exchanging species directly from anti-phase 1HN CEST profiles, along with an uncertainty associated with the predictions. The performance of the DNN was quantitatively assessed using both synthetic and experimental anti-phase CEST profiles. The assessments show that the DNN accurately determines chemical shifts and their associated uncertainties. The DNNs developed here do not contain any parameters for the end-user to adjust and the method therefore allows for autonomous analysis of complex NMR data that report on conformational exchange.
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Affiliation(s)
- Gogulan Karunanithy
- Division of Biosciences, Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, UK
| | - Tairan Yuwen
- Department of Pharmaceutical Analysis and State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Lewis E Kay
- Department of Molecular Genetics, University of Toronto, Toronto, ON, 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
- Program in Molecular Medicine, Hospital for Sick Children Research Institute, Toronto, ON, M5G 0A4, Canada
| | - D Flemming Hansen
- Division of Biosciences, Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, UK.
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6
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Invernici M, Trindade IB, Cantini F, Louro RO, Piccioli M. Measuring transverse relaxation in highly paramagnetic systems. JOURNAL OF BIOMOLECULAR NMR 2020; 74:431-442. [PMID: 32710399 PMCID: PMC7508935 DOI: 10.1007/s10858-020-00334-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 07/09/2020] [Indexed: 05/16/2023]
Abstract
The enhancement of nuclear relaxation rates due to the interaction with a paramagnetic center (known as Paramagnetic Relaxation Enhancement) is a powerful source of structural and dynamics information, widely used in structural biology. However, many signals affected by the hyperfine interaction relax faster than the evolution periods of common NMR experiments and therefore they are broadened beyond detection. This gives rise to a so-called blind sphere around the paramagnetic center, which is a major limitation in the use of PREs. Reducing the blind sphere is extremely important in paramagnetic metalloproteins. The identification, characterization, and proper structural restraining of the first coordination sphere of the metal ion(s) and its immediate neighboring regions is key to understand their biological function. The novel HSQC scheme we propose here, that we termed R2-weighted, HSQC-AP, achieves this aim by detecting signals that escaped detection in a conventional HSQC experiment and provides fully reliable R2 values in the range of 1H R2 rates ca. 50-400 s-1. Independently on the type of paramagnetic center and on the size of the molecule, this experiment decreases the radius of the blind sphere and increases the number of detectable PREs. Here, we report the validation of this approach for the case of PioC, a small protein containing a high potential 4Fe-4S cluster in the reduced [Fe4S4]2+ form. The blind sphere was contracted to a minimal extent, enabling the measurement of R2 rates for the cluster coordinating residues.
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Affiliation(s)
- Michele Invernici
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Inês B Trindade
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, Av. da República (EAN), 2780-157, Oeiras, Portugal
| | - Francesca Cantini
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Ricardo O Louro
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, Av. da República (EAN), 2780-157, Oeiras, Portugal.
| | - Mario Piccioli
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.
- Consorzio Interuniversitario Risonanze Magnetiche Di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.
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7
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Pell AJ, Pintacuda G, Grey CP. Paramagnetic NMR in solution and the solid state. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 111:1-271. [PMID: 31146806 DOI: 10.1016/j.pnmrs.2018.05.001] [Citation(s) in RCA: 215] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 05/11/2018] [Accepted: 05/12/2018] [Indexed: 05/22/2023]
Abstract
The field of paramagnetic NMR has expanded considerably in recent years. This review addresses both the theoretical description of paramagnetic NMR, and the way in which it is currently practised. We provide a review of the theory of the NMR parameters of systems in both solution and the solid state. Here we unify the different languages used by the NMR, EPR, quantum chemistry/DFT, and magnetism communities to provide a comprehensive and coherent theoretical description. We cover the theory of the paramagnetic shift and shift anisotropy in solution both in the traditional formalism in terms of the magnetic susceptibility tensor, and using a more modern formalism employing the relevant EPR parameters, such as are used in first-principles calculations. In addition we examine the theory first in the simple non-relativistic picture, and then in the presence of spin-orbit coupling. These ideas are then extended to a description of the paramagnetic shift in periodic solids, where it is necessary to include the bulk magnetic properties, such as magnetic ordering at low temperatures. The description of the paramagnetic shift is completed by describing the current understanding of such shifts due to lanthanide and actinide ions. We then examine the paramagnetic relaxation enhancement, using a simple model employing a phenomenological picture of the electronic relaxation, and again using a more complex state-of-the-art theory which incorporates electronic relaxation explicitly. An additional important consideration in the solid state is the impact of bulk magnetic susceptibility effects on the form of the spectrum, where we include some ideas from the field of classical electrodynamics. We then continue by describing in detail the solution and solid-state NMR methods that have been deployed in the study of paramagnetic systems in chemistry, biology, and the materials sciences. Finally we describe a number of case studies in paramagnetic NMR that have been specifically chosen to highlight how the theory in part one, and the methods in part two, can be used in practice. The systems chosen include small organometallic complexes in solution, solid battery electrode materials, metalloproteins in both solution and the solid state, systems containing lanthanide ions, and multi-component materials used in pharmaceutical controlled-release formulations that have been doped with paramagnetic species to measure the component domain sizes.
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Affiliation(s)
- Andrew J Pell
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Svante Arrhenius väg 16 C, SE-106 91 Stockholm, Sweden.
| | - Guido Pintacuda
- Institut des Sciences Analytiques (CNRS UMR 5280, ENS de Lyon, UCB Lyon 1), Université de Lyon, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Clare P Grey
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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8
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Tiwari VP, Pandit S, Vallurupalli P. Exchangeable deuterons introduce artifacts in amide 15N CEST experiments used to study protein conformational exchange. JOURNAL OF BIOMOLECULAR NMR 2019; 73:43-48. [PMID: 30661150 DOI: 10.1007/s10858-018-00223-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 12/27/2018] [Indexed: 06/09/2023]
Abstract
Protein molecules sample different conformations in solution and characterizing these conformations is crucial to understanding protein function. 15N CEST experiments are now routinely used to study slow conformational exchange of protein molecules between a 'visible' major state and 'invisible' minor states. These experiments have also been adapted to measure the solvent exchange rates of amide protons by exploiting the one bond deuterium isotope effect on the amide 15N chemical shifts. However at moderately high temperatures (~ 50 °C) that are sometimes required to populate protein minor conformers to levels (~ 1%) that can be detected by CEST experiments solvent H/D exchange can lead to 'dips' in low B115N CEST profiles that can be wrongly assigned to the conformational exchange process being characterized. This is demonstrated in the case of ~ 18 kDa T4 Lysozyme (T4L) at 50 °C and the ~ 11 kDa E. coli hibernation promoting factor (HPF) at 52 °C. This problem is trivially solved by eliminating the exchangeable deuterons in the solvent by using either an external D2O lock or by using a small amount (~ 1-3%) of a molecule like d6-DMSO that does not contain exchangeable deuterons to lock the spectrometer.
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Affiliation(s)
- Ved Prakash Tiwari
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, Telangana, 500107, India
| | - Subhendu Pandit
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, Telangana, 500107, India
| | - Pramodh Vallurupalli
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, Telangana, 500107, India.
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9
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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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10
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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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11
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Bertini I, Felli IC, Luchinat C, Parigi G, Pierattelli R. Towards a protocol for solution structure determination of copper(II) proteins: the case of Cu(II)Zn(II) superoxide dismutase. Chembiochem 2016; 8:1422-9. [PMID: 17583552 DOI: 10.1002/cbic.200700006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We have developed an optimized protocol to solve the solution structure of copper(II) proteins. After assignment, proton-proton NOEs are used for the shell where 1H spectra are conveniently observed. In a shell closer to the metal ion, 13C NMR spectra with band-selective homonuclear decoupling provide the assignment of all nuclei except for those of the metal ligands. A convenient method for the measurement of 13C longitudinal-relaxation rates (R1) of carbonyls and carboxylate moieties is proposed. 1H NOEs and 1H and 13C R1 data are sufficient to produce a good/reasonable solution structure, as demonstrated for a monomeric species of superoxide dismutase, a 153-residue protein.
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Affiliation(s)
- Ivano Bertini
- CERM and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
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12
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Jung SW, Lee K, Cho AE. Computational approaches to predict binding interactions between mammalian tyrosinases and (S)-(+)-decursin and its analogues as potent inhibitors. RSC Adv 2016. [DOI: 10.1039/c6ra09365e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Using computational methods, we elucidated the binding modes of (S)-(+)-decursin with mouse and human tyrosinases, and thereby provided insight to new tyrosinase inhibitors.
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Affiliation(s)
- Sang Won Jung
- Department of Bioinformatics
- Korea University
- Sejong 339-700
- Korea
| | - Kyeong Lee
- College of Pharmacy
- Dongguk University
- Koyang
- Korea
| | - Art E. Cho
- Department of Bioinformatics
- Korea University
- Sejong 339-700
- Korea
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13
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Vallurupalli P, Bouvignies G, Kay LE. A computational study of the effects of (13) C-(13) C scalar couplings on (13) C CEST NMR spectra: towards studies on a uniformly (13) C-labeled protein. Chembiochem 2013; 14:1709-13. [PMID: 23784752 DOI: 10.1002/cbic.201300230] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Indexed: 11/10/2022]
Abstract
Read the label: The NMR CEST experiment can be used to reconstruct spectra of sparsely populated, transiently formed protein conformers so long as they exchange with a highly populated ground state with rates of 20-300 s(-1) . Here we establish that accurate (13) C chemical shifts of side-chain carbon nuclei can be obtained from uniformly (13) C-labeled samples, without interference from the coupled (13) C spin network.
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Affiliation(s)
- Pramodh Vallurupalli
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, 1, King's College Circle, Toronto, Ontario, M5S 1A8 (Canada)
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14
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Kumara Swamy SK, Karczmarska A, Makowska-Janusik M, Kassiba A, Dittmer J. Solid-State NMR Correlation Experiments and Distance Measurements in Paramagnetic Metalorganics Exemplified by Cu-Cyclam. Chemphyschem 2013; 14:1864-70. [DOI: 10.1002/cphc.201300119] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Indexed: 11/11/2022]
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15
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Tierney DL. Jahn-Teller dynamics in a series of high-symmetry Co(II) chelates determine paramagnetic relaxation enhancements. J Phys Chem A 2012; 116:10959-72. [PMID: 23095055 DOI: 10.1021/jp309245e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
NMR paramagnetic relaxation enhancements (PREs) of a series of structurally characterized, trigonal bis-trispyrazolylborate (Tp) chelates of high-spin Co(II), spanning 100-850 MHz in field, are reported. Prior knowledge of the metal-nucleus distances allows numerical extraction of position-dependent electron spin relaxation rates (τ(c)(-1)) from direct measurement of the individual PREs of the four symmetry distinct protons in Co(Tp)(2), using available closed-form expressions. The data for this electronically complex system where spin-orbit coupling defines the ground state electronic structure are analyzed in terms of the Solomon-Bloembergen-Morgan (SBM) relations, as well as available zero-field splitting limit theories. A simple angular correction is shown to be sufficient to reconcile the individual τ(c)(T) data for the four classes of protons. The data identify a previously unrecognized dynamic Jahn-Teller effect in these historically important complexes, with a barrier of ~230 cm(-1), pointing to a level of dynamics in trispyrazolylborate chemistry that has not been described before, and further show that it is the Jahn-Teller that is responsible for the PREs in fluid solution. A field-dependent component is also identified for the two protons nearest g(//), which is suggested to arise due to Zeeman mixing of excited state character into the ground level.
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Affiliation(s)
- David L Tierney
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico 87131, United States.
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16
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Vallurupalli P, Bouvignies G, Kay LE. Studying “Invisible” Excited Protein States in Slow Exchange with a Major State Conformation. J Am Chem Soc 2012; 134:8148-61. [DOI: 10.1021/ja3001419] [Citation(s) in RCA: 353] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pramodh Vallurupalli
- Departments of Molecular
Genetics,
Biochemistry, and Chemistry, The University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Guillaume Bouvignies
- Departments of Molecular
Genetics,
Biochemistry, and Chemistry, The University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Lewis E. Kay
- Departments of Molecular
Genetics,
Biochemistry, and Chemistry, The University of Toronto, Toronto, Ontario, Canada M5S 1A8
- Program in Molecular Structure
and Function, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8
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17
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Hansen DF, Westler WM, Kunze MBA, Markley JL, Weinhold F, Led JJ. Accurate structure and dynamics of the metal-site of paramagnetic metalloproteins from NMR parameters using natural bond orbitals. J Am Chem Soc 2012; 134:4670-82. [PMID: 22329704 PMCID: PMC3303200 DOI: 10.1021/ja209348p] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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A natural bond orbital (NBO) analysis of unpaired electron
spin
density in metalloproteins is presented, which allows a fast and robust
calculation of paramagnetic NMR parameters. Approximately 90% of the
unpaired electron spin density occupies metal–ligand NBOs,
allowing the majority of the density to be modeled by only a few NBOs
that reflect the chemical bonding environment. We show that the paramagnetic
relaxation rate of protons can be calculated accurately using only
the metal–ligand NBOs and that these rates are in good agreement
with corresponding rates measured experimentally. This holds, in particular,
for protons of ligand residues where the point-dipole approximation
breaks down. To describe the paramagnetic relaxation of heavy nuclei,
also the electron spin density in the local orbitals must be taken
into account. Geometric distance restraints for 15N can
be derived from the paramagnetic relaxation enhancement and the Fermi
contact shift when local NBOs are included in the analysis. Thus,
the NBO approach allows us to include experimental paramagnetic NMR
parameters of 15N nuclei as restraints in a structure optimization
protocol. We performed a molecular dynamics simulation and structure
determination of oxidized rubredoxin using the experimentally obtained
paramagnetic NMR parameters of 15N. The corresponding structures
obtained are in good agreement with the crystal structure of rubredoxin.
Thus, the NBO approach allows an accurate description of the geometric
structure and the dynamics of metalloproteins, when NMR parameters
are available of nuclei in the immediate vicinity of the metal-site.
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Affiliation(s)
- D Flemming Hansen
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom.
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Koehler J, Meiler J. Expanding the utility of NMR restraints with paramagnetic compounds: background and practical aspects. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2011; 59:360-89. [PMID: 22027343 PMCID: PMC3202700 DOI: 10.1016/j.pnmrs.2011.05.001] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Accepted: 05/06/2011] [Indexed: 05/05/2023]
Affiliation(s)
- Julia Koehler
- Department of Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37232-8725, USA.
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Hansen DF, Kay LE. Determining Valine Side-Chain Rotamer Conformations in Proteins from Methyl 13C Chemical Shifts: Application to the 360 kDa Half-Proteasome. J Am Chem Soc 2011; 133:8272-81. [DOI: 10.1021/ja2014532] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- D. Flemming Hansen
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Lewis E. Kay
- Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto, Toronto, Ontario M5S 1A8, Canada
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21
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Lin IJ, Xia B, King DS, Machonkin TE, Westler WM, Markley JL. Hyperfine-shifted (13)C and (15)N NMR signals from Clostridium pasteurianum rubredoxin: extensive assignments and quantum chemical verification. J Am Chem Soc 2010; 131:15555-63. [PMID: 19799419 PMCID: PMC2766250 DOI: 10.1021/ja905928x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Stable isotope-labeling methods, coupled with novel techniques for detecting fast-relaxing NMR signals, now permit detailed investigations of paramagnetic centers of metalloproteins. We have utilized these advances to carry out comprehensive assignments of the hyperfine-shifted 13C and 15N signals of the rubredoxin from Clostridium pasteurianum (CpRd) in both its oxidized and reduced states. We used residue-specific labeling (by chemical synthesis) and residue-type-selective labeling (by biosynthesis) to assign signals detected by one-dimensional 15N NMR spectroscopy, to nitrogen atoms near the iron center. We refined and extended these 15N assignments to the adjacent carbonyl carbons by means of one-dimensional 13C[15N] decoupling difference experiments. We collected paramagnetic-optimized SuperWEFT 13C[13C] constant time COSY (SW-CT-COSY) data to complete the assignment of 13C signals of reduced CpRd. By following these 13C signals as the protein was gradually oxidized, we transferred these assignments to carbons in the oxidized state. We have compared these assignments with hyperfine chemical shifts calculated from available X-ray structures of CpRd in its oxidized and reduced forms. The results allow the evaluation of the X-ray structural models as representative of the solution structure of the protein, and they provide a framework for future investigation of the active site of this protein. The methods developed here should be applicable to other proteins that contain a paramagnetic center with high spin and slow electron exchange.
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Affiliation(s)
- I-Jin Lin
- Graduate Program in Biophysics, University of Wisconsin-Madison, 433 Babcock Drive, Madison, Wisconsin 53706, USA
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Rastrelli F, Bagno A. Predicting the NMR Spectra of Paramagnetic Molecules by DFT: Application to Organic Free Radicals and Transition-Metal Complexes. Chemistry 2009; 15:7990-8004. [DOI: 10.1002/chem.200802443] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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23
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Zhang Y, Oldfield E. NMR hyperfine shifts in blue copper proteins: a quantum chemical investigation. J Am Chem Soc 2008; 130:3814-23. [PMID: 18314973 DOI: 10.1021/ja075978b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present the results of the first quantum chemical investigations of 1H NMR hyperfine shifts in the blue copper proteins (BCPs): amicyanin, azurin, pseudoazurin, plastocyanin, stellacyanin, and rusticyanin. We find that very large structural models that incorporate extensive hydrogen bond networks, as well as geometry optimization, are required to reproduce the experimental NMR hyperfine shift results, the best theory vs experiment predictions having R2 = 0.94, a slope = 1.01, and a SD = 40.5 ppm (or approximately 4.7% of the overall approximately 860 ppm shift range). We also find interesting correlations between the hyperfine shifts and the bond and ring critical point properties computed using atoms-in-molecules theory, in addition to finding that hyperfine shifts can be well-predicted by using an empirical model, based on the geometry-optimized structures, which in the future should be of use in structure refinement.
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Affiliation(s)
- Yong Zhang
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
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Affiliation(s)
- Ivano Bertini
- Magnetic Resonance Center (CERM) and Department of Chemistry – University of Florence, via L. Sacconi 6, 50019 Sesto Fiorentino, Italy, Fax: +39‐055‐457‐4271
| | - Antonio Rosato
- Magnetic Resonance Center (CERM) and Department of Chemistry – University of Florence, via L. Sacconi 6, 50019 Sesto Fiorentino, Italy, Fax: +39‐055‐457‐4271
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