1
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Li GC, Castro MA, Ukwaththage T, Sanders CR. Optimizing NMR fragment-based drug screening for membrane protein targets. J Struct Biol X 2024; 9:100100. [PMID: 38883400 PMCID: PMC11176934 DOI: 10.1016/j.yjsbx.2024.100100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 05/05/2024] [Accepted: 05/20/2024] [Indexed: 06/18/2024] Open
Abstract
NMR spectroscopy has played a pivotal role in fragment-based drug discovery by coupling detection of weak ligand-target binding with structural mapping of the binding site. Fragment-based screening by NMR has been successfully applied to many soluble protein targets, but only to a limited number of membrane proteins, despite the fact that many drug targets are membrane proteins. This is partly because of difficulties preparing membrane proteins for NMR-especially human membrane proteins-and because of the inherent complexity associated with solution NMR spectroscopy on membrane protein samples, which require the inclusion of membrane-mimetic agents such as micelles, nanodiscs, or bicelles. Here, we developed a generalizable protocol for fragment-based screening of membrane proteins using NMR. We employed two human membrane protein targets, both in fully protonated detergent micelles: the single-pass C-terminal domain of the amyloid precursor protein, C99, and the tetraspan peripheral myelin protein 22 (PMP22). For both we determined the optimal NMR acquisition parameters, protein concentration, protein-to-micelle ratio, and upper limit to the concentration of D6-DMSO in screening samples. Furthermore, we conducted preliminary screens of a plate-format molecular fragment mixture library using our optimized conditions and were able to identify hit compounds that selectively bound to the respective target proteins. It is hoped that the approaches presented here will be useful in complementing existing methods for discovering lead compounds that target membrane proteins.
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Affiliation(s)
- Geoffrey C Li
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine - Basic Sciences, Nashville, TN 37240, USA
| | - Manuel A Castro
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine - Basic Sciences, Nashville, TN 37240, USA
| | - Thilini Ukwaththage
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine - Basic Sciences, Nashville, TN 37240, USA
| | - Charles R Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine - Basic Sciences, Nashville, TN 37240, USA
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2
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Mallis RJ, Lee JJ, den Berg AV, Brazin KN, Viennet T, Zmuda J, Cross M, Radeva D, Rodriguez‐Mias R, Villén J, Gelev V, Reinherz EL, Arthanari H. Efficient and economic protein labeling for NMR in mammalian expression systems: Application to a preT-cell and T-cell receptor protein. Protein Sci 2024; 33:e4950. [PMID: 38511503 PMCID: PMC10955624 DOI: 10.1002/pro.4950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/05/2024] [Accepted: 02/16/2024] [Indexed: 03/22/2024]
Abstract
Protein nuclear magnetic resonance (NMR) spectroscopy relies on the ability to isotopically label polypeptides, which is achieved through heterologous expression in various host organisms. Most commonly, Escherichia coli is employed by leveraging isotopically substituted ammonium and glucose to uniformly label proteins with 15N and 13C, respectively. Moreover, E. coli can grow and express proteins in uniformly deuterium-substituted water (D2O), a strategy useful for experiments targeting high molecular weight proteins. Unfortunately, many proteins, particularly those requiring specific posttranslational modifications like disulfide bonding or glycosylation for proper folding and/or function, cannot be readily expressed in their functional forms using E. coli-based expression systems. One such class of proteins includes T-cell receptors and their related preT-cell receptors. In this study, we present an expression system for isotopic labeling of proteins using a nonadherent human embryonic kidney cell line, Expi293F, and a specially designed media. We demonstrate the application of this platform to the β subunit common to both receptors. In addition, we show that this expression system and media can be used to specifically label amino acids Phe, Ile, Val, and Leu in this system, utilizing an amino acid-specific labeling protocol that allows targeted incorporation at high efficiency without significant isotopic scrambling. We demonstrate that this system can also be used to express proteins with fluorinated amino acids. We were routinely able to obtain an NMR sample with a concentration of 200 μM from 30 mL of culture media, utilizing less than 20 mg of the labeled amino acids.
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Affiliation(s)
- Robert J. Mallis
- Laboratory of ImmunobiologyDana‐Farber Cancer InstituteBostonMassachusettsUSA
- Department of Medical OncologyDana‐Farber Cancer InstituteBostonMassachusettsUSA
- Department of DermatologyHarvard Medical SchoolBostonMassachusettsUSA
| | - Jonathan J. Lee
- Laboratory of ImmunobiologyDana‐Farber Cancer InstituteBostonMassachusettsUSA
- Department of Medical OncologyDana‐Farber Cancer InstituteBostonMassachusettsUSA
| | | | - Kristine N. Brazin
- Laboratory of ImmunobiologyDana‐Farber Cancer InstituteBostonMassachusettsUSA
- Department of Medical OncologyDana‐Farber Cancer InstituteBostonMassachusettsUSA
- Department of MedicineHarvard Medical SchoolBostonMassachusettsUSA
| | - Thibault Viennet
- Department of Cancer BiologyDana‐Farber Cancer InstituteBostonMassachusettsUSA
- Department of Biological Chemistry and Molecular PharmacologyHarvard Medical SchoolBostonMassachusettsUSA
| | | | | | - Denitsa Radeva
- Faculty of Chemistry and PharmacySofia UniversitySofiaBulgaria
| | | | - Judit Villén
- Department of Genome SciencesUniversity of WashingtonSeattleWashingtonUSA
| | - Vladimir Gelev
- Faculty of Chemistry and PharmacySofia UniversitySofiaBulgaria
| | - Ellis L. Reinherz
- Laboratory of ImmunobiologyDana‐Farber Cancer InstituteBostonMassachusettsUSA
- Department of Medical OncologyDana‐Farber Cancer InstituteBostonMassachusettsUSA
- Department of MedicineHarvard Medical SchoolBostonMassachusettsUSA
| | - Haribabu Arthanari
- Department of Cancer BiologyDana‐Farber Cancer InstituteBostonMassachusettsUSA
- Department of Biological Chemistry and Molecular PharmacologyHarvard Medical SchoolBostonMassachusettsUSA
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3
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Prosser RS, Alonzi NA. Discerning conformational dynamics and binding kinetics of GPCRs by 19F NMR. Curr Opin Pharmacol 2023; 72:102377. [PMID: 37612172 DOI: 10.1016/j.coph.2023.102377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/08/2023] [Accepted: 03/13/2023] [Indexed: 08/25/2023]
Abstract
19F NMR provides a way of monitoring conformational dynamics of G-protein coupled receptors (GPCRs) from the perspective of an ensemble. While X-ray crystallography provides exquisitely resolved high-resolution structures of specific states, it generally does not recapitulate the true ensemble of functional states. Fluorine (19F) NMR provides a highly sensitive spectroscopic window into the conformational ensemble, generally permitting the direct quantification of resolvable states. Moreover, straightforward T1- and T2-based relaxation experiments allow for the study of fluctuations within a given state and exchange between states, on timescales spanning nanoseconds to seconds. Conveniently, most biological systems are free of fluorine. Thus, via fluorinated amino acid analogues or thiol-reactive fluorinated tags, F or CF3 reporters can be site specifically incorporated into proteins of interest. In this review, fluorine labeling protocols and 19F NMR experiments will be presented, from the perspective of small molecule NMR (i.e. drug or small molecule interactions with receptors) or macromolecular NMR (i.e. conformational dynamics of receptors and receptor-G-protein complexes).
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Affiliation(s)
- R S Prosser
- Chemistry Department, University of Toronto, CPS UTM, Davis Building, Rm 4052, 3359 Mississauga Rd North, Mississauga, Ontario, L5L 1C6, Canada; Biochemistry Department, University of Toronto, CPS UTM, Davis Building, Rm 4052, 3359 Mississauga Rd North, Mississauga, Ontario, L5L 1C6, Canada.
| | - Nicholas A Alonzi
- Chemistry Department, University of Toronto, CPS UTM, Davis Building, Rm 4052, 3359 Mississauga Rd North, Mississauga, Ontario, L5L 1C6, Canada
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4
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Nag R, Joshi S, Rathore AS, Majumder S. Profiling Enzyme Activity of l-Asparaginase II by NMR-Based Methyl Fingerprinting at Natural Abundance. J Am Chem Soc 2023; 145:10826-10838. [PMID: 37154467 DOI: 10.1021/jacs.3c02154] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
l-asparaginase II (MW 135 kDa) from E. coli is an FDA-approved protein drug used for the treatment of childhood leukemia. Despite its long history as a chemotherapeutic, the structural basis of enzyme action, in solution, remains widely contested. In this work, methyl-based 2D [1H-13C]-heteronuclear single-quantum correlation (HSQC) NMR, at natural abundance, has been used to profile the enzymatic activity of the commercially available enzyme drug. The [1H-13C]-HSQC NMR spectra of the protein reveal the role of a flexible loop segment in the activity of the enzyme, in solution. Addition of asparagine to the protein results in distinct conformational changes of the loop that could be signatures of intermediates formed in the catalytic reaction. To this end, an isothermal titration calorimetry (ITC)-based assay has been developed to measure the enzymatic reaction enthalpy, as a marker for its activity. Combining both ITC and NMR, it was shown that the disruption of the protein conformation can result in the loss of function. The scope, robustness, and validity of the loop fingerprints in relation to enzyme activity have been tested under different solution conditions. Overall, our results indicate that 2D NMR can be used reliably to gauge the structure-function of this enzyme, bypassing the need to label the protein. Such natural abundant NMR methods can be potentially extended to probe the structure-function aspects of high-molecular-weight protein therapeutics (glycosylated protein drugs, enzymes, therapeutic monoclonal antibodies, antibody-drug conjugates, and Fc-fusion proteins), where (a) flexible loops are required for their function and (b) isotope labeling may not be straightforward.
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Affiliation(s)
- Rachayita Nag
- Biophysics & Structural Genomics, Saha Institute of Nuclear Physics, Kolkata 700064, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Srishti Joshi
- Department of Chemical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India
| | - Anurag Singh Rathore
- Department of Chemical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India
| | - Subhabrata Majumder
- Biophysics & Structural Genomics, Saha Institute of Nuclear Physics, Kolkata 700064, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
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5
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Nedielkov R, Möller HM. Detecting and Characterizing Interactions of Metabolites with Proteins by Saturation Transfer Difference Nuclear Magnetic Resonance (STD NMR) Spectroscopy. Methods Mol Biol 2023; 2554:123-139. [PMID: 36178624 DOI: 10.1007/978-1-0716-2624-5_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Saturation transfer difference (STD) nuclear magnetic resonance (NMR) spectroscopy is an established technique for detecting and characterizing the binding of small molecules, such as metabolites, to biological macromolecules like proteins and nucleic acids. STD NMR allows detection of binding in complex mixtures of potential ligands, which is often used for library screening in the pharmaceutical industry but may also be beneficial for binding studies with metabolite mixtures. The nature of the ligand is normally restricted to small molecules in terms of NMR spectroscopy, and the size of the macromolecule on the other side should be larger than 10-15 kDa. This technique is especially applicable to detecting binders of intermediate to low affinity with the dissociation constant (KD) above 1 μM. In this chapter, we focus on recent developments and the applications of STD NMR to studying interactions of natural products and metabolites, in particular. The reader is also referred to excellent reviews of the field and the literature cited therein. This chapter also provides a detailed experimental protocol for performing the STD NMR measurement based on the example of the subunit A of the Na+-transporting NADH/ubiquinone oxidoreductase (Na+-NQR) from V. cholerae interacting with its natural quinone substrate and inhibitors.
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Affiliation(s)
- Ruslan Nedielkov
- University of Potsdam, Institute for Chemistry, Potsdam, Germany.
| | - Heiko M Möller
- University of Potsdam, Institute for Chemistry, Potsdam, Germany
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6
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Aguion PI, Marchanka A, Carlomagno T. Nucleic acid-protein interfaces studied by MAS solid-state NMR spectroscopy. J Struct Biol X 2022; 6:100072. [PMID: 36090770 PMCID: PMC9449856 DOI: 10.1016/j.yjsbx.2022.100072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/11/2022] [Accepted: 08/15/2022] [Indexed: 11/20/2022] Open
Abstract
Solid-state NMR (ssNMR) has become a well-established technique to study large and insoluble protein assemblies. However, its application to nucleic acid-protein complexes has remained scarce, mainly due to the challenges presented by overlapping nucleic acid signals. In the past decade, several efforts have led to the first structure determination of an RNA molecule by ssNMR. With the establishment of these tools, it has become possible to address the problem of structure determination of nucleic acid-protein complexes by ssNMR. Here we review first and more recent ssNMR methodologies that study nucleic acid-protein interfaces by means of chemical shift and peak intensity perturbations, direct distance measurements and paramagnetic effects. At the end, we review the first structure of an RNA-protein complex that has been determined from ssNMR-derived intermolecular restraints.
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Affiliation(s)
- Philipp Innig Aguion
- Institute for Organic Chemistry and Centre of Biomolecular Drug Research (BMWZ), Leibniz University Hannover, Schneiderberg 38, 30167 Hannover, Germany
| | - Alexander Marchanka
- Institute for Organic Chemistry and Centre of Biomolecular Drug Research (BMWZ), Leibniz University Hannover, Schneiderberg 38, 30167 Hannover, Germany
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Teresa Carlomagno
- School of Biosciences/College of Life and Enviromental Sciences, Institute of Cancer and Genomic Sciences/College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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7
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Mühlberg L, Alarcin T, Maass T, Creutznacher R, Küchler R, Mallagaray A. Ligand-induced structural transitions combined with paramagnetic ions facilitate unambiguous NMR assignments of methyl groups in large proteins. JOURNAL OF BIOMOLECULAR NMR 2022; 76:59-74. [PMID: 35397749 PMCID: PMC9247001 DOI: 10.1007/s10858-022-00394-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 03/24/2022] [Indexed: 06/14/2023]
Abstract
NMR spectroscopy allows the study of biomolecules in close-to-native conditions. Structural information can be inferred from the NMR spectra when an assignment is available. Protein assignment is usually a time-consuming task, being specially challenging in the case of large, supramolecular systems. Here, we present an extension of existing state-of-the-art strategies for methyl group assignment that partially overcomes signal overlapping and other difficulties associated to isolated methyl groups. Our approach exploits the ability of proteins to populate two or more conformational states, allowing for unique NOE restraints in each protein conformer. The method is compatible with automated assignment algorithms, granting assignments beyond the limits of a single protein state. The approach also benefits from long-range structural restraints obtained from metal-induced pseudocontact shifts (PCS) and paramagnetic relaxation enhancements (PREs). We illustrate the method with the complete assignment of the 199 methyl groups of a MILproSVproSAT methyl-labeled sample of the UDP-glucose pyrophosphorylase enzyme from Leishmania major (LmUGP). Protozoan parasites of the genus Leishmania causes Leishmaniasis, a neglected disease affecting over 12 million people worldwide. LmUGP is responsible for the de novo biosynthesis of uridine diphosphate-glucose, a precursor in the biosynthesis of the dense surface glycocalyx involved in parasite survival and infectivity. NMR experiments with LmUGP and related enzymes have the potential to unravel new insights in the host resistance mechanisms used by Leishmania major. Our efforts will help in the development of selective and efficient drugs against Leishmania.
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Affiliation(s)
- Lars Mühlberg
- Institute for Chemistry and Metabolomics, Centre for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany
| | - Tuncay Alarcin
- Institute for Chemistry and Metabolomics, Centre for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany
| | - Thorben Maass
- Institute for Chemistry and Metabolomics, Centre for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany
| | - Robert Creutznacher
- Institute for Chemistry and Metabolomics, Centre for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany
| | - Richard Küchler
- Institute for Chemistry and Metabolomics, Centre for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany
| | - Alvaro Mallagaray
- Institute for Chemistry and Metabolomics, Centre for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany.
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8
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Felli IC, Bermel W, Pierattelli R. Exclusively heteronuclear NMR experiments for the investigation of intrinsically disordered proteins: focusing on proline residues. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:511-522. [PMID: 37904768 PMCID: PMC10539766 DOI: 10.5194/mr-2-511-2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 06/02/2021] [Indexed: 11/01/2023]
Abstract
NMR represents a key spectroscopic technique that contributes to the emerging field of highly flexible, intrinsically disordered proteins (IDPs) or protein regions (IDRs) that lack a stable three-dimensional structure. A set of exclusively heteronuclear NMR experiments tailored for proline residues, highly abundant in IDPs/IDRs, are presented here. They provide a valuable complement to the widely used approach based on amide proton detection, filling the gap introduced by the lack of amide protons in proline residues within polypeptide chains. The novel experiments have very interesting properties for the investigations of IDPs/IDRs of increasing complexity.
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Affiliation(s)
- Isabella C. Felli
- CERM and Department of Chemistry “Ugo Schiff”, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Wolfgang Bermel
- Bruker BioSpin GmbH, Silberstreifen 4, 76287 Rheinstetten, Germany
| | - Roberta Pierattelli
- CERM and Department of Chemistry “Ugo Schiff”, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
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9
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Abstract
The 26S proteasome is the most complex ATP-dependent protease machinery, of ~2.5 MDa mass, ubiquitously found in all eukaryotes. It selectively degrades ubiquitin-conjugated proteins and plays fundamentally indispensable roles in regulating almost all major aspects of cellular activities. To serve as the sole terminal "processor" for myriad ubiquitylation pathways, the proteasome evolved exceptional adaptability in dynamically organizing a large network of proteins, including ubiquitin receptors, shuttle factors, deubiquitinases, AAA-ATPase unfoldases, and ubiquitin ligases, to enable substrate selectivity and processing efficiency and to achieve regulation precision of a vast diversity of substrates. The inner working of the 26S proteasome is among the most sophisticated, enigmatic mechanisms of enzyme machinery in eukaryotic cells. Recent breakthroughs in three-dimensional atomic-level visualization of the 26S proteasome dynamics during polyubiquitylated substrate degradation elucidated an extensively detailed picture of its functional mechanisms, owing to progressive methodological advances associated with cryogenic electron microscopy (cryo-EM). Multiple sites of ubiquitin binding in the proteasome revealed a canonical mode of ubiquitin-dependent substrate engagement. The proteasome conformation in the act of substrate deubiquitylation provided insights into how the deubiquitylating activity of RPN11 is enhanced in the holoenzyme and is coupled to substrate translocation. Intriguingly, three principal modes of coordinated ATP hydrolysis in the heterohexameric AAA-ATPase motor were discovered to regulate intermediate functional steps of the proteasome, including ubiquitin-substrate engagement, deubiquitylation, initiation of substrate translocation and processive substrate degradation. The atomic dissection of the innermost working of the 26S proteasome opens up a new era in our understanding of the ubiquitin-proteasome system and has far-reaching implications in health and disease.
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Affiliation(s)
- Youdong Mao
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, 02215, Massachusetts, USA. .,School of Physics, Center for Quantitative Biology, Peking University, Beijing, 100871, China.
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10
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Lacabanne D, Boudet J, Malär AA, Wu P, Cadalbert R, Salmon L, Allain FHT, Meier BH, Wiegand T. Protein Side-Chain-DNA Contacts Probed by Fast Magic-Angle Spinning NMR. J Phys Chem B 2020; 124:11089-11097. [PMID: 33238710 PMCID: PMC7734624 DOI: 10.1021/acs.jpcb.0c08150] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
![]()
Protein–nucleic
acid interactions are essential in a variety
of biological events ranging from the replication of genomic DNA to
the synthesis of proteins. Noncovalent interactions guide such molecular
recognition events, and protons are often at the center of them, particularly
due to their capability of forming hydrogen bonds to the nucleic acid
phosphate groups. Fast magic-angle spinning experiments (100 kHz)
reduce the proton NMR line width in solid-state NMR of fully protonated
protein–DNA complexes to such an extent that resolved proton
signals from side-chains coordinating the DNA can be detected. We
describe a set of NMR experiments focusing on the detection of protein
side-chains from lysine, arginine, and aromatic amino acids and discuss
the conclusions that can be obtained on their role in DNA coordination.
We studied the 39 kDa enzyme of the archaeal pRN1 primase complexed
with DNA and characterize protein–DNA contacts in the presence
and absence of bound ATP molecules.
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Affiliation(s)
| | - Julien Boudet
- Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | | | - Pengzhi Wu
- Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.,Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | | | - Loic Salmon
- Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Frédéric H-T Allain
- Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.,Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Beat H Meier
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Thomas Wiegand
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
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11
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Behera SP, Dubey A, Chen WN, De Paula VS, Zhang M, Sgourakis NG, Bermel W, Wagner G, Coote PW, Arthanari H. Nearest-neighbor NMR spectroscopy: categorizing spectral peaks by their adjacent nuclei. Nat Commun 2020; 11:5547. [PMID: 33144564 PMCID: PMC7642304 DOI: 10.1038/s41467-020-19325-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 10/01/2020] [Indexed: 01/12/2023] Open
Abstract
Methyl-NMR enables atomic-resolution studies of structure and dynamics of large proteins in solution. However, resonance assignment remains challenging. The problem is to combine existing structural informational with sparse distance restraints and search for the most compatible assignment among the permutations. Prior classification of peaks as either from isoleucine, leucine, or valine reduces the search space by many orders of magnitude. However, this is hindered by overlapped leucine and valine frequencies. In contrast, the nearest-neighbor nuclei, coupled to the methyl carbons, resonate in distinct frequency bands. Here, we develop a framework to imprint additional information about passively coupled resonances onto the observed peaks. This depends on simultaneously orchestrating closely spaced bands of resonances along different magnetization trajectories, using principles from control theory. For methyl-NMR, the method is implemented as a modification to the standard fingerprint spectrum (the 2D-HMQC). The amino acid type is immediately apparent in the fingerprint spectrum. There is no additional relaxation loss or an increase in experimental time. The method is validated on biologically relevant proteins. The idea of generating new spectral information using passive, adjacent resonances is applicable to other contexts in NMR spectroscopy.
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Affiliation(s)
- Soumya P Behera
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Abhinav Dubey
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - Wan-Na Chen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Viviane S De Paula
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, 95064, USA
| | - Meng Zhang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Nikolaos G Sgourakis
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, 95064, USA
| | - Wolfgang Bermel
- Magnetic Resonance Spectroscopy NMR Application, Bruker BioSpin GmbH, 76287, Rheinstetten, Germany
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Paul W Coote
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.
| | - Haribabu Arthanari
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.
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12
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Beikzadeh M, Latham MP. The dynamic nature of the Mre11-Rad50 DNA break repair complex. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 163:14-22. [PMID: 33121960 DOI: 10.1016/j.pbiomolbio.2020.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 10/02/2020] [Accepted: 10/23/2020] [Indexed: 01/18/2023]
Abstract
The Mre11-Rad50-Nbs1/Xrs2 protein complex plays a pivotal role in the detection and repair of DNA double strand breaks. Through traditional and emerging structural biology techniques, various functional structural states of this complex have been visualized; however, relatively little is known about the transitions between these states. Indeed, it is these structural transitions that are important for Mre11-Rad50-mediated DNA unwinding at a break and the activation of downstream repair signaling events. Here, we present a brief overview of the current understanding of the structure of the core Mre11-Rad50 complex. We then highlight our recent studies emphasizing the contributions of solution state NMR spectroscopy and other biophysical techniques in providing insight into the structures and dynamics associated with Mre11-Rad50 functions.
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Affiliation(s)
- Mahtab Beikzadeh
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Michael P Latham
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA.
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13
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Sarkar D, Olejniczak ET, Phan J, Coker JA, Sai J, Arnold A, Beesetty Y, Waterson AG, Fesik SW. Discovery of Sulfonamide-Derived Agonists of SOS1-Mediated Nucleotide Exchange on RAS Using Fragment-Based Methods. J Med Chem 2020; 63:8325-8337. [PMID: 32673492 DOI: 10.1021/acs.jmedchem.0c00511] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The nucleotide exchange factor Son of Sevenless (SOS) catalyzes the activation of RAS by converting it from its inactive GDP-bound state to its active GTP-bound state. Recently, we have reported the discovery of small-molecule allosteric activators of SOS1 that can increase the amount of RAS-GTP in cells. The compounds can inhibit ERK phosphorylation at higher concentrations by engaging a feedback mechanism. To further study this process, we sought different chemical matter from an NMR-based fragment screen using selective methyl labeling. To aid this process, several Ile methyl groups located in different binding sites of the protein were assigned and used to categorize the NMR hits into different classes. Hit to lead optimization using an iterative structure-based design paradigm resulted in compounds with improvements in binding affinity. These improved molecules of a different chemical class increase SOS1cat-mediated nucleotide exchange on RAS and display cellular action consistent with our prior results.
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Affiliation(s)
- Dhruba Sarkar
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
| | - Edward T Olejniczak
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
| | - Jason Phan
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
| | - Jesse A Coker
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
| | - Jiqing Sai
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
| | - Allison Arnold
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
| | - Yugandhar Beesetty
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
| | - Alex G Waterson
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States.,Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37232-0146, United States
| | - Stephen W Fesik
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States.,Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States.,Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37232-0146, United States
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14
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Danmaliki GI, Hwang PM. Solution NMR spectroscopy of membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183356. [PMID: 32416193 DOI: 10.1016/j.bbamem.2020.183356] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 05/08/2020] [Accepted: 05/10/2020] [Indexed: 02/06/2023]
Abstract
Integral membrane proteins (IMPs) perform unique and indispensable functions in the cell, making them attractive targets for fundamental research and drug discovery. Developments in protein production, isotope labeling, sample preparation, and pulse sequences have extended the utility of solution NMR spectroscopy for studying IMPs with multiple transmembrane segments. Here we review some recent applications of solution NMR for studying structure, dynamics, and interactions of polytopic IMPs, emphasizing strategies used to overcome common technical challenges.
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Affiliation(s)
- Gaddafi I Danmaliki
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Peter M Hwang
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada; Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
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15
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Wiegand T. A solid-state NMR tool box for the investigation of ATP-fueled protein engines. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 117:1-32. [PMID: 32471533 DOI: 10.1016/j.pnmrs.2020.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 06/11/2023]
Abstract
Motor proteins are involved in a variety of cellular processes. Their main purpose is to convert the chemical energy released during adenosine triphosphate (ATP) hydrolysis into mechanical work. In this review, solid-state Nuclear Magnetic Resonance (NMR) approaches are discussed allowing studies of structures, conformational events and dynamic features of motor proteins during a variety of enzymatic reactions. Solid-state NMR benefits from straightforward sample preparation based on sedimentation of the proteins directly into the Magic-Angle Spinning (MAS) rotor. Protein resonance assignment is the crucial and often time-limiting step in interpreting the wealth of information encoded in the NMR spectra. Herein, potentials, challenges and limitations in resonance assignment for large motor proteins are presented, focussing on both biochemical and spectroscopic approaches. This work highlights NMR tools available to study the action of the motor domain and its coupling to functional processes, as well as to identify protein-nucleotide interactions during events such as DNA replication. Arrested protein states of reaction coordinates such as ATP hydrolysis can be trapped for NMR studies by using stable, non-hydrolysable ATP analogues that mimic the physiological relevant states as accurately as possible. Recent advances in solid-state NMR techniques ranging from Dynamic Nuclear Polarization (DNP), 31P-based heteronuclear correlation experiments, 1H-detected spectra at fast MAS frequencies >100 kHz to paramagnetic NMR are summarized and their applications to the bacterial DnaB helicase from Helicobacter pylori are discussed.
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Affiliation(s)
- Thomas Wiegand
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland.
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16
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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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17
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Arthanari H, Takeuchi K, Dubey A, Wagner G. Emerging solution NMR methods to illuminate the structural and dynamic properties of proteins. Curr Opin Struct Biol 2019; 58:294-304. [PMID: 31327528 PMCID: PMC6778509 DOI: 10.1016/j.sbi.2019.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 06/03/2019] [Accepted: 06/10/2019] [Indexed: 12/20/2022]
Abstract
The first recognition of protein breathing was more than 50 years ago. Today, we are able to detect the multitude of interaction modes, structural polymorphisms, and binding-induced changes in protein structure that direct function. Solution-state NMR spectroscopy has proved to be a powerful technique, not only to obtain high-resolution structures of proteins, but also to provide unique insights into the functional dynamics of proteins. Here, we summarize recent technical landmarks in solution NMR that have enabled characterization of key biological macromolecular systems. These methods have been fundamental to atomic resolution structure determination and quantitative analysis of dynamics over a wide range of time scales by NMR. The ability of NMR to detect lowly populated protein conformations and transiently formed complexes plays a critical role in its ability to elucidate functionally important structural features of proteins and their dynamics.
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Affiliation(s)
- Haribabu Arthanari
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, United States; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, United States.
| | - Koh Takeuchi
- Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, 135-0064 Tokyo, Japan.
| | - Abhinav Dubey
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, United States; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, United States
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, United States.
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18
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Mallis RJ, Brazin KN, Duke-Cohan JS, Hwang W, Wang JH, Wagner G, Arthanari H, Lang MJ, Reinherz EL. NMR: an essential structural tool for integrative studies of T cell development, pMHC ligand recognition and TCR mechanobiology. JOURNAL OF BIOMOLECULAR NMR 2019; 73:319-332. [PMID: 30815789 PMCID: PMC6693947 DOI: 10.1007/s10858-019-00234-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 02/06/2019] [Indexed: 05/05/2023]
Abstract
Early studies of T cell structural biology using X-ray crystallography, surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) focused on a picture of the αβT cell receptor (αβTCR) component domains and their cognate ligands (peptides bound to MHC molecules, i.e. pMHCs) as static interaction partners. Moving forward requires integrating this corpus of data with dynamic technologies such as NMR, molecular dynamics (MD) simulations and real-time single molecule (SM) studies exemplified by optical tweezers (OT). NMR bridges relevant timescales and provides the potential for an all-atom dynamic description of αβTCR components prior to and during interactions with binding partners. SM techniques have opened up vistas in understanding the non-equilibrium nature of T cell signaling through the introduction of force-mediated binding measurements into the paradigm for T cell function. In this regard, bioforces consequent to T-lineage cell motility are now perceived as placing piconewton (pN)-level loads on single receptor-pMHC bonds to impact structural change and αβT-lineage biology, including peptide discrimination, cellular activation, and developmental progression. We discuss herein essential NMR technologies in illuminating the role of ligand binding in the preT cell receptor (preTCR), the αβTCR developmental precursor, and convergence of NMR, SM and MD data in advancing our comprehension of T cell development. More broadly we review the central hypothesis that the αβTCR is a mechanosensor, fostered by breakthrough NMR-based structural insights. Collectively, elucidating dynamic aspects through the integrative use of NMR, SM, and MD shall advance fundamental appreciation of the mechanism of T cell signaling as well as inform translational efforts in αβTCR and chimeric T cell (CAR-T) immunotherapies and T cell vaccinology.
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Affiliation(s)
- Robert J Mallis
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Department of Dermatology, Harvard Medical School, Boston, MA, 02115, USA
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
| | - Kristine N Brazin
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Jonathan S Duke-Cohan
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Wonmuk Hwang
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843, USA
- Department of Materials Science & Engineering, Texas A&M University, College Station, TX, 77843, USA
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, 02455, Republic of Korea
| | - Jia-Huai Wang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Haribabu Arthanari
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
| | - Matthew J Lang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37235, USA.
| | - Ellis L Reinherz
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA.
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19
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Casiraghi M, Point E, Pozza A, Moncoq K, Banères JL, Catoire LJ. NMR analysis of GPCR conformational landscapes and dynamics. Mol Cell Endocrinol 2019; 484:69-77. [PMID: 30690069 DOI: 10.1016/j.mce.2018.12.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/13/2018] [Accepted: 12/24/2018] [Indexed: 12/22/2022]
Abstract
Understanding the signal transduction mechanism mediated by the G Protein-Coupled Receptors (GPCRs) in eukaryote cells represents one of the main issues in modern biology. At the molecular level, various biophysical approaches have provided important insights on the functional plasticity of these complex allosteric machines. In this context, X-ray crystal structures published during the last decade represent a major breakthrough in GPCR structural biology, delivering important information on the activation process of these receptors through the description of the three-dimensional organization of their active and inactive states. In complement to crystals and cryo-electronic microscopy structures, information on the probability of existence of different GPCR conformations and the dynamic barriers separating those structural sub-states is required to better understand GPCR function. Among the panel of techniques available, nuclear magnetic resonance (NMR) spectroscopy represents a powerful tool to characterize both conformational landscapes and dynamics. Here, we will outline the potential of NMR to address such biological questions, and we will illustrate the functional insights that NMR has brought in the field of GPCRs in the recent years.
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Affiliation(s)
- Marina Casiraghi
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, UMR7099, CNRS/Université; Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique (FRC 550), 13 rue Pierre et Marie Curie, 75005, Paris, France
| | - Elodie Point
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, UMR7099, CNRS/Université; Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique (FRC 550), 13 rue Pierre et Marie Curie, 75005, Paris, France
| | - Alexandre Pozza
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, UMR7099, CNRS/Université; Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique (FRC 550), 13 rue Pierre et Marie Curie, 75005, Paris, France
| | - Karine Moncoq
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, UMR7099, CNRS/Université; Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique (FRC 550), 13 rue Pierre et Marie Curie, 75005, Paris, France
| | - Jean-Louis Banères
- Institut des Biomoléćules Max Mousseron (IBMM), UMR 5247 CNRS, Université; Montpellier, ENSCM, 15 av. Charles Flahault, 34093, Montpellier, France
| | - Laurent J Catoire
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, UMR7099, CNRS/Université; Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique (FRC 550), 13 rue Pierre et Marie Curie, 75005, Paris, France.
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20
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Li Y, Soubias O, Li J, Sun S, Randazzo PA, Byrd RA. Functional Expression and Characterization of Human Myristoylated-Arf1 in Nanodisc Membrane Mimetics. Biochemistry 2019; 58:1423-1431. [PMID: 30735034 DOI: 10.1021/acs.biochem.8b01323] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lipidated small GTP-binding proteins of the Arf family interact with multiple cellular partners and with membranes to regulate intracellular traffic and organelle structure. Here, we focus on the ADP-ribosylation factor 1 (Arf1), which interacts with numerous proteins in the Arf pathway, such as the ArfGAP ASAP1 that is highly expressed and activated in several cancer cell lines and associated with enhanced migration, invasiveness, and poor prognosis. Understanding the molecular and mechanistic details of Arf1 regulation at the membrane via structural and biophysical studies requires large quantities of fully functional protein bound to lipid bilayers. Here, we report on the production of a functional human Arf1 membrane platform on nanodiscs for biophysical studies. Large scale bacterial production of highly pure, N-myristoylated human Arf1 has been achieved, including complex isotopic labeling for nuclear magnetic resonance (NMR) studies, and the myr-Arf1 can be readily assembled in small nanoscale lipid bilayers (nanodiscs, NDs). It is determined that myr-Arf1 requires a minimum binding surface in the NDs of ∼20 lipids. Fluorescence and NMR were used to establish nucleotide exchange and ArfGAP-stimulated GTP hydrolysis at the membrane, indicating that phophoinositide stimulation of the activity of the ArfGAP ASAP1 is ≥2000-fold. Differences in nonhydrolyzable GTP analogues are observed, and GMPPCP is found to be the most stable. Combined, these observations establish a functional environment for biophysical studies of Arf1 effectors and interactions at the membrane.
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Affiliation(s)
- Yifei Li
- Structural Biophysics Laboratory, Center for Cancer Research , National Cancer Institute , Frederick , Maryland 21702-1201 , United States
| | - Olivier Soubias
- Structural Biophysics Laboratory, Center for Cancer Research , National Cancer Institute , Frederick , Maryland 21702-1201 , United States
| | - Jess Li
- Structural Biophysics Laboratory, Center for Cancer Research , National Cancer Institute , Frederick , Maryland 21702-1201 , United States
| | - Shangjin Sun
- Structural Biophysics Laboratory, Center for Cancer Research , National Cancer Institute , Frederick , Maryland 21702-1201 , United States
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research , National Cancer Institute , Bethesda , Maryland 20892 , United States
| | - R Andrew Byrd
- Structural Biophysics Laboratory, Center for Cancer Research , National Cancer Institute , Frederick , Maryland 21702-1201 , United States
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21
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22
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Demers JP, Fricke P, Shi C, Chevelkov V, Lange A. Structure determination of supra-molecular assemblies by solid-state NMR: Practical considerations. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:51-78. [PMID: 30527136 DOI: 10.1016/j.pnmrs.2018.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 06/15/2018] [Accepted: 06/15/2018] [Indexed: 05/26/2023]
Abstract
In the cellular environment, biomolecules assemble in large complexes which can act as molecular machines. Determining the structure of intact assemblies can reveal conformations and inter-molecular interactions that are only present in the context of the full assembly. Solid-state NMR (ssNMR) spectroscopy is a technique suitable for the study of samples with high molecular weight that allows the atomic structure determination of such large protein assemblies under nearly physiological conditions. This review provides a practical guide for the first steps of studying biological supra-molecular assemblies using ssNMR. The production of isotope-labeled samples is achievable via several means, which include recombinant expression, cell-free protein synthesis, extraction of assemblies directly from cells, or even the study of assemblies in whole cells in situ. Specialized isotope labeling schemes greatly facilitate the assignment of chemical shifts and the collection of structural data. Advanced strategies such as mixed, diluted, or segmental subunit labeling offer the possibility to study inter-molecular interfaces. Detailed and practical considerations are presented with respect to first setting up magic-angle spinning (MAS) ssNMR experiments, including the selection of the ssNMR rotor, different methods to best transfer the sample and prepare the rotor, as well as common and robust procedures for the calibration of the instrument. Diagnostic spectra to evaluate the resolution and sensitivity of the sample are presented. Possible improvements that can reduce sample heterogeneity and improve the quality of ssNMR spectra are reviewed.
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Affiliation(s)
- Jean-Philippe Demers
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany; Laboratory of Cell Biology, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Pascal Fricke
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Chaowei Shi
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Veniamin Chevelkov
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Adam Lange
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany; Institut für Biologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany.
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23
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Suzuki R, Sakakura M, Mori M, Fujii M, Akashi S, Takahashi H. Methyl-selective isotope labeling using α-ketoisovalerate for the yeast Pichia pastoris recombinant protein expression system. JOURNAL OF BIOMOLECULAR NMR 2018; 71:213-223. [PMID: 29869771 DOI: 10.1007/s10858-018-0192-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 05/29/2018] [Indexed: 06/08/2023]
Abstract
Methyl-detected NMR spectroscopy is a useful tool for investigating the structures and interactions of large macromolecules such as membrane proteins. The procedures for preparation of methyl-specific isotopically-labeled proteins were established for the Escherichia coli (E. coli) expression system, but typically it is not feasible to express eukaryotic proteins using E. coli. The Pichia pastoris (P. pastoris) expression system is the most common yeast expression system, and is known to be superior to the E. coli system for the expression of mammalian proteins, including secretory and membrane proteins. However, this system has not yet been optimized for methyl-specific isotope labeling, especially for Val/Leu-methyl specific isotope incorporation. To overcome this difficulty, we explored various culture conditions for the yeast cells to efficiently uptake Val/Leu precursors. Among the searched conditions, we found that the cultivation pH has a critical effect on Val/Leu precursor uptake. At an acidic cultivation pH, the uptake of the Val/Leu precursor was increased, and methyl groups of Val and Leu in the synthesized recombinant protein yielded intense 1H-13C correlation signals. Based on these results, we present optimized protocols for the Val/Leu-methyl-selective 13C incorporation by the P. pastoris expression system.
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Affiliation(s)
- Rika Suzuki
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Masayoshi Sakakura
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Masaki Mori
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Moe Fujii
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Satoko Akashi
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Hideo Takahashi
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
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24
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Huang C, Kalodimos CG. Structures of Large Protein Complexes Determined by Nuclear Magnetic Resonance Spectroscopy. Annu Rev Biophys 2017; 46:317-336. [DOI: 10.1146/annurev-biophys-070816-033701] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Chengdong Huang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
| | - Charalampos G. Kalodimos
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
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25
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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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26
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Cassaignau AME, Launay HMM, Karyadi ME, Wang X, Waudby CA, Deckert A, Robertson AL, Christodoulou J, Cabrita LD. A strategy for co-translational folding studies of ribosome-bound nascent chain complexes using NMR spectroscopy. Nat Protoc 2016; 11:1492-507. [PMID: 27466710 DOI: 10.1038/nprot.2016.101] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
During biosynthesis on the ribosome, an elongating nascent polypeptide chain can begin to fold, in a process that is central to all living systems. Detailed structural studies of co-translational protein folding are now beginning to emerge; such studies were previously limited, at least in part, by the inherently dynamic nature of emerging nascent chains, which precluded most structural techniques. NMR spectroscopy is able to provide atomic-resolution information for ribosome-nascent chain complexes (RNCs), but it requires large quantities (≥10 mg) of homogeneous, isotopically labeled RNCs. Further challenges include limited sample working concentration and stability of the RNC sample (which contribute to weak NMR signals) and resonance broadening caused by attachment to the large (2.4-MDa) ribosomal complex. Here, we present a strategy to generate isotopically labeled RNCs in Escherichia coli that are suitable for NMR studies. Uniform translational arrest of the nascent chains is achieved using a stalling motif, and isotopically labeled RNCs are produced at high yield using high-cell-density E. coli growth conditions. Homogeneous RNCs are isolated by combining metal affinity chromatography (to isolate ribosome-bound species) with sucrose density centrifugation (to recover intact 70S monosomes). Sensitivity-optimized NMR spectroscopy is then applied to the RNCs, combined with a suite of parallel NMR and biochemical analyses to cross-validate their integrity, including RNC-optimized NMR diffusion measurements to report on ribosome attachment in situ. Comparative NMR studies of RNCs with the analogous isolated proteins permit a high-resolution description of the structure and dynamics of a nascent chain during its progressive biosynthesis on the ribosome.
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Affiliation(s)
- Anaïs M E Cassaignau
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, University of London, London, UK
| | - Hélène M M Launay
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, University of London, London, UK
| | - Maria-Evangelia Karyadi
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, University of London, London, UK
| | - Xiaolin Wang
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, University of London, London, UK
| | - Christopher A Waudby
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, University of London, London, UK
| | - Annika Deckert
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, University of London, London, UK
| | - Amy L Robertson
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, University of London, London, UK
| | - John Christodoulou
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, University of London, London, UK
| | - Lisa D Cabrita
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, University of London, London, UK
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Alderson TR, Kim JH, Markley JL. Dynamical Structures of Hsp70 and Hsp70-Hsp40 Complexes. Structure 2016; 24:1014-30. [PMID: 27345933 DOI: 10.1016/j.str.2016.05.011] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 05/05/2016] [Accepted: 05/10/2016] [Indexed: 12/25/2022]
Abstract
Protein misfolding and aggregation are pathological events that place a significant amount of stress on the maintenance of protein homeostasis (proteostasis). For prevention and repair of protein misfolding and aggregation, cells are equipped with robust mechanisms that mainly rely on molecular chaperones. Two classes of molecular chaperones, heat shock protein 70 kDa (Hsp70) and Hsp40, recognize and bind to misfolded proteins, preventing their toxic biomolecular aggregation and enabling refolding or targeted degradation. Here, we review the current state of structural biology of Hsp70 and Hsp40-Hsp70 complexes and examine the link between their structures, dynamics, and functions. We highlight the power of nuclear magnetic resonance spectroscopy to untangle complex relationships behind molecular chaperones and their mechanism(s) of action.
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Affiliation(s)
- Thomas Reid Alderson
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3TA, UK; Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Jin Hae Kim
- National Magnetic Resonance Facility at Madison, Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - John Lute Markley
- National Magnetic Resonance Facility at Madison, Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA
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Martelli T, Ravera E, Louka A, Cerofolini L, Hafner M, Fragai M, Becker CFW, Luchinat C. Atomic-Level Quality Assessment of Enzymes Encapsulated in Bioinspired Silica. Chemistry 2015; 22:425-32. [DOI: 10.1002/chem.201503613] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Indexed: 12/23/2022]
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Ardenkjaer-Larsen JH, Boebinger GS, Comment A, Duckett S, Edison AS, Engelke F, Griesinger C, Griffin RG, Hilty C, Maeda H, Parigi G, Prisner T, Ravera E, van Bentum J, Vega S, Webb A, Luchinat C, Schwalbe H, Frydman L. Facing and Overcoming Sensitivity Challenges in Biomolecular NMR Spectroscopy. Angew Chem Int Ed Engl 2015; 54:9162-85. [PMID: 26136394 PMCID: PMC4943876 DOI: 10.1002/anie.201410653] [Citation(s) in RCA: 216] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 01/26/2015] [Indexed: 11/07/2022]
Abstract
In the Spring of 2013, NMR spectroscopists convened at the Weizmann Institute in Israel to brainstorm on approaches to improve the sensitivity of NMR experiments, particularly when applied in biomolecular settings. This multi-author interdisciplinary Review presents a state-of-the-art description of the primary approaches that were considered. Topics discussed included the future of ultrahigh-field NMR systems, emerging NMR detection technologies, new approaches to nuclear hyperpolarization, and progress in sample preparation. All of these are orthogonal efforts, whose gains could multiply and thereby enhance the sensitivity of solid- and liquid-state experiments. While substantial advances have been made in all these areas, numerous challenges remain in the quest of endowing NMR spectroscopy with the sensitivity that has characterized forms of spectroscopies based on electrical or optical measurements. These challenges, and the ways by which scientists and engineers are striving to solve them, are also addressed.
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Affiliation(s)
- Jan-Henrik Ardenkjaer-Larsen
- GE Healthcare, Broendby, Denmark; Department of Electrical Engineering, Technical University of Denmark, Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre (Denmark)
| | - Gregory S Boebinger
- U.S. National High Magnetic Field Lab, Florida State University, Tallahassee, FL 32310 (USA)
| | - Arnaud Comment
- Institute of Physics of Biological Systems, Ecole Polytechnique Fédérale de Lausanne, Lausanne (Switzerland)
| | - Simon Duckett
- Department of Chemistry, University of York, Heslington, York, YO10 5DD (UK)
| | - Arthur S Edison
- Department of Biochemistry & Molecular Biology, University of Florida, Gainesville, FL 32610 (USA)
| | | | | | - Robert G Griffin
- Department of Chemistry and Francis Bitter Magnet Lab, MIT, Cambridge, MA 02139-4703 (USA)
| | - Christian Hilty
- Department of Chemistry, Texas A&M University, College Station (USA)
| | - Hidaeki Maeda
- Riken Center for Life Science Technologies, Yokohama, Kanagawa (Japan)
| | - Giacomo Parigi
- CERM and Department of Chemistry, University of Florence, Sesto Fiorentino (Italy)
| | - Thomas Prisner
- Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt am Main (Germany)
| | - Enrico Ravera
- CERM and Department of Chemistry, University of Florence, Sesto Fiorentino (Italy)
| | | | - Shimon Vega
- Chemical Physics Department, Weizmann Institute of Science, Rehovot (Israel)
| | - Andrew Webb
- Department of Radiology, C. J. Gorter Center for High Field MRI, Leiden University Medical Center (The Netherlands)
| | - Claudio Luchinat
- CERM and Department of Chemistry, University of Florence, Sesto Fiorentino (Italy).
| | - Harald Schwalbe
- Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt am Main (Germany).
| | - Lucio Frydman
- Chemical Physics Department, Weizmann Institute of Science, Rehovot (Israel).
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30
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Ardenkjaer-Larsen JH, Boebinger GS, Comment A, Duckett S, Edison AS, Engelke F, Griesinger C, Griffin RG, Hilty C, Maeda H, Parigi G, Prisner T, Ravera E, van Bentum J, Vega S, Webb A, Luchinat C, Schwalbe H, Frydman L. Neue Ansätze zur Empfindlichkeitssteigerung in der biomolekularen NMR-Spektroskopie. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201410653] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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31
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Burmann BM, Hiller S. Chaperones and chaperone-substrate complexes: Dynamic playgrounds for NMR spectroscopists. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2015; 86-87:41-64. [PMID: 25919198 DOI: 10.1016/j.pnmrs.2015.02.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/19/2015] [Accepted: 02/19/2015] [Indexed: 05/20/2023]
Abstract
The majority of proteins depend on a well-defined three-dimensional structure to obtain their functionality. In the cellular environment, the process of protein folding is guided by molecular chaperones to avoid misfolding, aggregation, and the generation of toxic species. To this end, living cells contain complex networks of molecular chaperones, which interact with substrate polypeptides by a multitude of different functionalities: transport them towards a target location, help them fold, unfold misfolded species, resolve aggregates, or deliver them towards a proteolysis machinery. Despite the availability of high-resolution crystal structures of many important chaperones in their substrate-free apo forms, structural information about how substrates are bound by chaperones and how they are protected from misfolding and aggregation is very sparse. This lack of information arises from the highly dynamic nature of chaperone-substrate complexes, which so far has largely hindered their crystallization. This highly dynamic nature makes chaperone-substrate complexes good targets for NMR spectroscopy. Here, we review the results achieved by NMR spectroscopy to understand chaperone function in general and details of chaperone-substrate interactions in particular. We assess the information content and applicability of different NMR techniques for the characterization of chaperones and chaperone-substrate complexes. Finally, we highlight three recent studies, which have provided structural descriptions of chaperone-substrate complexes at atomic resolution.
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Affiliation(s)
- Björn M Burmann
- Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
| | - Sebastian Hiller
- Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland.
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32
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Michel E, Allain FHT. Selective Amino Acid Segmental Labeling of Multi-Domain Proteins. Methods Enzymol 2015; 565:389-422. [DOI: 10.1016/bs.mie.2015.05.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Prosser RS, Kim TH. Nuts and Bolts of CF3 and CH 3 NMR Toward the Understanding of Conformational Exchange of GPCRs. Methods Mol Biol 2015; 1335:39-51. [PMID: 26260593 DOI: 10.1007/978-1-4939-2914-6_4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
With the advent of efficient protein expression and functional purification protocols, it is now possible to reconstitute many G protein-coupled receptors (GPCRs) in detergent micelles at concentrations of 25 μM or more. Such concentrations are sufficient for studies of conformational states and dynamics relating to function and the mechanism of activation of GPCRs, using solution state NMR. In particular, methyl spectroscopy, in the form of one-dimensional (19)F NMR or two-dimensional ((1)H,(13)C) NMR, provides high fidelity spectra which reveal detailed features associated with conformational states and their lifetimes, as a function of ligand. While X-ray crystallography provides exquisitely detailed structures of lowest energy states associated with ligands, G proteins, and other proteins, NMR is able to validate such states, while providing insight into higher energy states that form part of the conformational landscape and are involved in activation. Through relaxation experiments spanning microseconds to seconds, lifetimes of these functional states can often be measured. By determining the effect of ligands on both equilibrium populations and rates of interconversion between states, it becomes possible to understand activation in terms of an ensemble description and in turn relate the ensemble to pharmaceutical phenomena.
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Affiliation(s)
- R Scott Prosser
- Department of Chemistry, University of Toronto (UTM), 3359 Mississauga Road North, Mississauga, ON, Canada, L5L 1C6,
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Barb AW. Intramolecular N-glycan/polypeptide interactions observed at multiple N-glycan remodeling steps through [(13)C,(15)N]-N-acetylglucosamine labeling of immunoglobulin G1. Biochemistry 2014; 54:313-22. [PMID: 25551295 PMCID: PMC4302832 DOI: 10.1021/bi501380t] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
Asparagine-linked (N) glycosylation
is a common eukaryotic protein
modification that affects protein folding, function, and stability
through intramolecular interactions between N-glycan
and polypeptide residues. Attempts to characterize the structure–activity
relationship of each N-glycan are hindered by inherent
properties of the glycoprotein, including glycan conformational and
compositional heterogeneity. These limitations can be addressed by
using a combination of nuclear magnetic resonance techniques following
enzymatic glycan remodeling to simultaneously generate homogeneous
glycoforms. However, widely applicable methods do not yet exist. To
address this technological gap, immature glycoforms of the immunoglobulin
G1 fragment crystallizable (Fc) were isolated in a homogeneous state
and enzymatically remodeled with [13C,15N]-N-acetylglucosamine (GlcNAc). UDP-[13C,15N]GlcNAc was synthesized enzymatically in a one-pot reaction from
[13C]glucose and [15N-amido]glutamine. Modifying Fc with recombinantly expressed glycosyltransferases
(Gnt1 and Gnt2) and UDP-[13C,15N]GlcNAc resulted
in complete glycoform conversion as judged by mass spectrometry. Two-dimensional
heteronuclear single-quantum coherence spectra of the Gnt1 product,
containing a single [13C,15N]GlcNAc residue
on each N-glycan, showed that the N-glycan is stabilized through interactions with polypeptide residues.
Similar spectra of homogeneous glycoforms, halted at different points
along the N-glycan remodeling pathway, revealed the
presence of an increased level of interaction between the N-glycan and polypeptide at each step, including mannose
trimming, as the N-glycan was converted to a complex-type,
biantennary form. Thus, conformational restriction increases as Fc N-glycan maturation proceeds. Gnt1 and Gnt2 catalyze fundamental
reactions in the synthesis of every glycoprotein with a complex-type N-glycan; thus, the strategies presented herein can be applied
to a broad range of glycoprotein studies.
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Affiliation(s)
- Adam W Barb
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States
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35
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Nematollahi LA, Garza-Garcia A, Bechara C, Esposito D, Morgner N, Robinson CV, Driscoll PC. Flexible stoichiometry and asymmetry of the PIDDosome core complex by heteronuclear NMR spectroscopy and mass spectrometry. J Mol Biol 2014; 427:737-752. [PMID: 25528640 PMCID: PMC4332690 DOI: 10.1016/j.jmb.2014.11.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 11/14/2014] [Accepted: 11/22/2014] [Indexed: 11/24/2022]
Abstract
Homotypic death domain (DD)–DD interactions are important in the assembly of oligomeric signaling complexes such as the PIDDosome that acts as a platform for activation of caspase-2-dependent apoptotic signaling. The structure of the PIDDosome core complex exhibits an asymmetric three-layered arrangement containing five PIDD-DDs in one layer, five RAIDD-DDs in a second layer and an additional two RAIDD-DDs. We addressed complex formation between PIDD-DD and RAIDD-DD in solution using heteronuclear nuclear magnetic resonance (NMR) spectroscopy, nanoflow electrospray ionization mass spectrometry and size-exclusion chromatography with multi-angle light scattering. The DDs assemble into complexes displaying molecular masses in the range 130–158 kDa and RAIDD-DD:PIDD-DD stoichiometries of 5:5, 6:5 and 7:5. These data suggest that the crystal structure is representative of only the heaviest species in solution and that two RAIDD-DDs are loosely attached to the 5:5 core. Two-dimensional 1H,15N-NMR experiments exhibited signal loss upon complexation consistent with the formation of high-molecular-weight species. 13C-Methyl-transverse relaxation optimized spectroscopy measurements of the PIDDosome core exhibit signs of differential line broadening, cross-peak splitting and chemical shift heterogeneity that reflect the presence of non-equivalent sites at interfaces within an asymmetric complex. Experiments using a mutant RAIDD-DD that forms a monodisperse 5:5 complex with PIDD-DD show that the spectroscopic signature derives from the quasi- but non-exact equivalent environments of each DD. Since this characteristic was previously demonstrated for the complex between the DDs of CD95 and FADD, the NMR data for this system are consistent with the formation of a structure homologous to the PIDDosome core. The PIDDosome core particle that has been crystallized as a 7:5 complex displays heterogeneous stoichiometry in solution. Methyl-transverse relaxation optimized spectroscopy NMR spectra for the complex suggest that individual PIDD-DDs and RAIDD-DDs experience non-equivalent environments in the PIDDosome core. A mutant PIDDosome core particle that is monodisperse displays similar NMR features, suggesting that the complexity of the spectra is a reflection of the absence of formal symmetry consistent with the crystal structure. The NMR characteristics are reminiscent of those reported for the complex formed between the DDs of CD95 and FADD, suggesting that this latter complex has similar architecture to the PIDDosome core.
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Affiliation(s)
- Lily A Nematollahi
- Division of Molecular Structure, Medical Research Council, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Acely Garza-Garcia
- Division of Molecular Structure, Medical Research Council, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Chérine Bechara
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Diego Esposito
- Division of Molecular Structure, Medical Research Council, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Nina Morgner
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Carol V Robinson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Paul C Driscoll
- Division of Molecular Structure, Medical Research Council, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK.
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36
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Kalverda AP, Gowdy J, Thompson GS, Homans SW, Henderson PJF, Patching SG. TROSY NMR with a 52 kDa sugar transport protein and the binding of a small-molecule inhibitor. Mol Membr Biol 2014; 31:131-40. [DOI: 10.3109/09687688.2014.911980] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Lee JH, Okuno Y, Cavagnero S. Sensitivity enhancement in solution NMR: emerging ideas and new frontiers. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 241:18-31. [PMID: 24656077 PMCID: PMC3967054 DOI: 10.1016/j.jmr.2014.01.005] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/14/2014] [Accepted: 01/17/2014] [Indexed: 05/05/2023]
Abstract
Modern NMR spectroscopy has reached an unprecedented level of sophistication in the determination of biomolecular structure and dynamics at atomic resolution in liquids. However, the sensitivity of this technique is still too low to solve a variety of cutting-edge biological problems in solution, especially those that involve viscous samples, very large biomolecules or aggregation-prone systems that need to be kept at low concentration. Despite the challenges, a variety of efforts have been carried out over the years to increase sensitivity of NMR spectroscopy in liquids. This review discusses basic concepts, recent developments and future opportunities in this exciting area of research.
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Affiliation(s)
- Jung Ho Lee
- Department of Chemistry and Biophysics Program, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322, USA
| | - Yusuke Okuno
- Department of Chemistry and Biophysics Program, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322, USA
| | - Silvia Cavagnero
- Department of Chemistry and Biophysics Program, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322, USA.
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39
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Hass MAS, Ubbink M. Structure determination of protein–protein complexes with long-range anisotropic paramagnetic NMR restraints. Curr Opin Struct Biol 2014; 24:45-53. [DOI: 10.1016/j.sbi.2013.11.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 11/22/2013] [Accepted: 11/22/2013] [Indexed: 10/25/2022]
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Abstract
This chapter describes reports of the structural characterization of death ligands and death receptors (DRs) from the tumor necrosis factor (TNF) and TNF receptor families. The review discusses the interactions of these proteins with agonist ligands, inhibitors, and downstream signaling molecules. Though historically labeled as being implicated in programmed cell death, the function of these proteins extends to nonapoptotic pathways. The review highlights, from a structural biology perspective, the complexity of DR signaling and the ongoing challenge to discern the precise mechanisms that occur at the point of DR activation, including how the degree to which the receptors are induced to cluster may be related to the nature of the impact upon the cell. The potential for posttranslational modification and receptor internalization to play roles in DR signaling is briefly discussed.
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Affiliation(s)
- Paul C Driscoll
- Division of Molecular Structure, Medical Research Council, National Institute for Medical Research, London, United Kingdom.
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41
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Chang YG, Tseng R, Kuo NW, LiWang A. Nuclear magnetic resonance spectroscopy of the circadian clock of cyanobacteria. Integr Comp Biol 2013; 53:93-102. [PMID: 23667047 DOI: 10.1093/icb/ict054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The most well-understood circadian clock at the level of molecular mechanisms is that of cyanobacteria. This overview is on how solution-state nuclear magnetic resonance (NMR) spectroscopy has contributed to this understanding. By exciting atomic spin-½ nuclei in a strong magnetic field, NMR obtains information on their chemical environments, inter-nuclear distances, orientations, and motions. NMR protein samples are typically aqueous, often at near-physiological pH, ionic strength, and temperature. The level of information obtainable by NMR depends on the quality of the NMR sample, by which we mean the solubility and stability of proteins. Here, we use examples from our laboratory to illustrate the advantages and limitations of the technique.
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Affiliation(s)
- Yong-Gang Chang
- School of Natural Sciences, University of California at Merced, Merced, CA 95343, USA
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42
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Lichtenecker RJ, Coudevylle N, Konrat R, Schmid W. Selective isotope labelling of leucine residues by using α-ketoacid precursor compounds. Chembiochem 2013; 14:818-21. [PMID: 23564734 DOI: 10.1002/cbic.201200737] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Indexed: 01/26/2023]
Abstract
You can have one without the other: A new metabolic precursor compound can selectively introduce (13)C and (2)H patterns at leucine residues in proteins in cell-based expression systems without interfering with valine metabolism. The protocol provides selectively labelled macromolecules well suited for probing structure and dynamics in high-molecular-weight proteins by NMR spectroscopy.
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Affiliation(s)
- Roman J Lichtenecker
- Institute of Organic Chemistry, University of Vienna, Währingerstrasse 38, 1090 Vienna, Austria.
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43
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Skinner SP, Moshev M, Hass MAS, Keizers PHJ, Ubbink M. PARAssign--paramagnetic NMR assignments of protein nuclei on the basis of pseudocontact shifts. JOURNAL OF BIOMOLECULAR NMR 2013; 55:379-89. [PMID: 23526169 DOI: 10.1007/s10858-013-9722-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 03/14/2013] [Indexed: 05/07/2023]
Abstract
The use of paramagnetic NMR data for the refinement of structures of proteins and protein complexes is widespread. However, the power of paramagnetism for protein assignment has not yet been fully exploited. PARAssign is software that uses pseudocontact shift data derived from several paramagnetic centers attached to the protein to obtain amide and methyl assignments. The ability of PARAssign to perform assignment when the positions of the paramagnetic centers are known and unknown is demonstrated. PARAssign has been tested using synthetic data for methyl assignment of a 47 kDa protein, and using both synthetic and experimental data for amide assignment of a 14 kDa protein. The complex fitting space involved in such an assignment procedure necessitates that good starting conditions are found, both regarding placement and strength of paramagnetic centers. These starting conditions are obtained through automated tensor placement and user-defined tensor parameters. The results presented herein demonstrate that PARAssign is able to successfully perform resonance assignment in large systems with a high degree of reliability. This software provides a method for obtaining the assignments of large systems, which may previously have been unassignable, by using 2D NMR spectral data and a known protein structure.
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Affiliation(s)
- Simon P Skinner
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
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Tugarinov V, Kay LE. Estimating side-chain order in [U-2H;13CH3]-labeled high molecular weight proteins from analysis of HMQC/HSQC spectra. J Phys Chem B 2013; 117:3571-7. [PMID: 23458382 DOI: 10.1021/jp401088c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A simple approach for quantification of methyl-containing side-chain mobility in high molecular weight methyl-protonated, uniformly deuterated proteins is described, based on the measurement of peak intensities in methyl (1)H-(13)C HMQC and HSQC correlation maps and relaxation rates of slowly decaying components of methyl (1)H-(13)C multiple-quantum coherences. A strength of the method is that [U-(2)H;(13)CH3]-labeled protein samples are required that are typically available at an early stage of any analysis. The utility of the methodology is demonstrated with applications to three protein systems ranging in molecular weight from 82 to 670 kDa. Although the approach is only semiquantitative, a high correlation between order parameters extracted via this scheme and other more established methods is nevertheless demonstrated.
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Affiliation(s)
- Vitali Tugarinov
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
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Abstract
The proteasome refers to a collection of complexes centered on the 20S proteasome core particle (20S CP), a complex of 28 subunits that houses proteolytic sites in its hollow interior. Proteasomes are found in eukaryotes, archaea, and some eubacteria, and their activity is critical for many cellular pathways. Important recent advances include inhibitor binding studies and the structure of the immunoproteasome, whose specificity is altered by the incorporation of inducible catalytic subunits. The inherent repression of the 20S CP is relieved by the ATP-independent activators 11S and Blm10/PA200, whose structures reveal principles of proteasome mechanism. The structure of the ATP-dependent 19S regulatory particle, which mediates degradation of polyubiquitylated proteins, is being revealed by a combination of crystal or NMR structures of individual subunits and electron microscopy reconstruction of the intact complex. Other recent structural advances inform us about mechanisms of assembly and the role of conformational changes in the functional cycle.
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Affiliation(s)
- Erik Kish-Trier
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112-5650, USA
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Barrett PJ, Chen J, Cho MK, Kim JH, Lu Z, Mathew S, Peng D, Song Y, Van Horn WD, Zhuang T, Sönnichsen FD, Sanders CR. The quiet renaissance of protein nuclear magnetic resonance. Biochemistry 2013; 52:1303-20. [PMID: 23368985 DOI: 10.1021/bi4000436] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
From roughly 1985 through the start of the new millennium, the cutting edge of solution protein nuclear magnetic resonance (NMR) spectroscopy was to a significant extent driven by the aspiration to determine structures. Here we survey recent advances in protein NMR that herald a renaissance in which a number of its most important applications reflect the broad problem-solving capability displayed by this method during its classical era during the 1970s and early 1980s.
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Affiliation(s)
- Paul J Barrett
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232-8725, United States
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Michel E, Skrisovska L, Wüthrich K, Allain FHT. Amino Acid-Selective Segmental Isotope Labeling of Multidomain Proteins for Structural Biology. Chembiochem 2013; 14:457-66. [DOI: 10.1002/cbic.201200732] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Indexed: 11/12/2022]
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48
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Hattori Y, Furuita K, Ohki I, Ikegami T, Fukada H, Shirakawa M, Fujiwara T, Kojima C. Utilization of lysine ¹³C-methylation NMR for protein-protein interaction studies. JOURNAL OF BIOMOLECULAR NMR 2013; 55:19-31. [PMID: 23224986 DOI: 10.1007/s10858-012-9675-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 09/10/2012] [Indexed: 05/20/2023]
Abstract
Chemical modification is an easy way for stable isotope labeling of non-labeled proteins. The reductive (13)C-methylation of the amino group of the lysine side-chain by (13)C-formaldehyde is a post-modification and is applicable to most proteins since this chemical modification specifically and quickly proceeds under mild conditions such as 4 °C, pH 6.8, overnight. (13)C-methylation has been used for NMR to study the interactions between the methylated proteins and various molecules, such as small ligands, nucleic acids and peptides. Here we applied lysine (13)C-methylation NMR to monitor protein-protein interactions. The affinity and the intermolecular interaction sites of methylated ubiquitin with three ubiquitin-interacting proteins were successfully determined using chemical-shift perturbation experiments via the (1)H-(13)C HSQC spectra of the (13)C-methylated-lysine methyl groups. The lysine (13)C-methylation NMR results also emphasized the importance of the usage of side-chain signals to monitor the intermolecular interaction sites, and was applicable to studying samples with concentrations in the low sub-micromolar range.
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Affiliation(s)
- Yoshikazu Hattori
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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Chan PHW, Weissbach S, Okon M, Withers SG, McIntosh LP. Nuclear magnetic resonance spectral assignments of α-1,4-galactosyltransferase LgtC from Neisseria meningitidis: substrate binding and multiple conformational states. Biochemistry 2012; 51:8278-92. [PMID: 22992161 DOI: 10.1021/bi3010279] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Lipopolysaccharide α-1,4-galactosyltransferase C (LgtC) from Neisseria meningitidis is responsible for a key step in lipooligosaccharide biosynthesis involving the transfer of α-galactose from the sugar donor UDP-galactose to a terminal acceptor lactose. Crystal structures of the complexes of LgtC with Mn(2+) and the sugar donor analogue UDP-2-deoxy-2-fluorogalactose in the absence and presence of the sugar acceptor analogue 4'-deoxylactose provided key insights into the galactosyl-transfer mechanism. Combined with kinetic analyses, the enzymatic mechanism of LgtC appears to involve a "front-side attack" S(N)i-like mechanism with a short-lived oxocarbenium-phosphate ion pair intermediate. As a prerequisite for investigating the required roles of structural dynamics in this catalytic mechanism by nuclear magnetic resonance techniques, the transverse relaxation-optimized amide (15)N heteronuclear single-quantum correlation and methyl (13)C heteronuclear multiple-quantum correlation spectra of LgtC in its apo, substrate analogue, and product complexes were partially assigned. This was accomplished using a suite of complementary spectroscopic approaches, combined with selective isotopic labeling and mutagenesis of all the isoleucine residues in the protein. Only ~70% of the amide signals could be detected, whereas more than the expected number of methyl signals were observed, indicating that LgtC adopts multiple interconverting conformational states. Chemical shift perturbation mapping provided insights into substrate and product binding, including the demonstration that the sugar donor analogue (UDP-2FGal) associates with LgtC only in the presence of a metal ion (Mg(2+)). These spectral assignments provide the foundation for detailed studies of the conformational dynamics of LgtC.
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Affiliation(s)
- Patrick H W Chan
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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Rhythmic ring-ring stacking drives the circadian oscillator clockwise. Proc Natl Acad Sci U S A 2012; 109:16847-51. [PMID: 22967510 DOI: 10.1073/pnas.1211508109] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The oscillator of the circadian clock of cyanobacteria is composed of three proteins, KaiA, KaiB, and KaiC, which together generate a self-sustained ∼24-h rhythm of phosphorylation of KaiC. The mechanism propelling this oscillator has remained elusive, however. We show that stacking interactions between the CI and CII rings of KaiC drive the transition from the phosphorylation-specific KaiC-KaiA interaction to the dephosphorylation-specific KaiC-KaiB interaction. We have identified the KaiB-binding site, which is on the CI domain. This site is hidden when CI domains are associated as a hexameric ring. However, stacking of the CI and CII rings exposes the KaiB-binding site. Because the clock output protein SasA also binds to CI and competes with KaiB for binding, ring stacking likely regulates clock output. We demonstrate that ADP can expose the KaiB-binding site in the absence of ring stacking, providing an explanation for how it can reset the clock.
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