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Toke O. Three Decades of REDOR in Protein Science: A Solid-State NMR Technique for Distance Measurement and Spectral Editing. Int J Mol Sci 2023; 24:13637. [PMID: 37686450 PMCID: PMC10487747 DOI: 10.3390/ijms241713637] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 08/30/2023] [Accepted: 09/01/2023] [Indexed: 09/10/2023] Open
Abstract
Solid-state NMR (ss-NMR) is a powerful tool to investigate noncrystallizable, poorly soluble molecular systems, such as membrane proteins, amyloids, and cell walls, in environments that closely resemble their physical sites of action. Rotational-echo double resonance (REDOR) is an ss-NMR methodology, which by reintroducing heteronuclear dipolar coupling under magic angle spinning conditions provides intramolecular and intermolecular distance restraints at the atomic level. In addition, REDOR can be exploited as a selection tool to filter spectra based on dipolar couplings. Used extensively as a spectroscopic ruler between isolated spins in site-specifically labeled systems and more recently as a building block in multidimensional ss-NMR pulse sequences allowing the simultaneous measurement of multiple distances, REDOR yields atomic-scale information on the structure and interaction of proteins. By extending REDOR to the determination of 1H-X dipolar couplings in recent years, the limit of measurable distances has reached ~15-20 Å, making it an attractive method of choice for the study of complex biomolecular assemblies. Following a methodological introduction including the most recent implementations, examples are discussed to illustrate the versatility of REDOR in the study of biological systems.
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Affiliation(s)
- Orsolya Toke
- Laboratory for NMR Spectroscopy, Structural Research Centre, Research Centre for Natural Sciences, 2 Magyar tudósok körútja, H-1117 Budapest, Hungary
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2
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de Oliveira FFM, Mamillapalli S, Gonti S, Brey RN, Li H, Schiffer J, Casadevall A, Bann JG. Binding of the von Willebrand Factor A Domain of Capillary Morphogenesis Protein 2 to Anthrax Protective Antigen Vaccine Reduces Immunogenicity in Mice. mSphere 2020; 5:e00556-19. [PMID: 31941807 PMCID: PMC6968648 DOI: 10.1128/msphere.00556-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 12/09/2019] [Indexed: 11/24/2022] Open
Abstract
Protective antigen (PA) is a component of anthrax toxin that can elicit toxin-neutralizing antibody responses. PA is also the major antigen in the current vaccine to prevent anthrax, but stability problems with recombinant proteins have complicated the development of new vaccines containing recombinant PA. The relationship between antigen physical stability and immunogenicity is poorly understood, but there are theoretical reasons to think that this parameter can affect immune responses. We investigated the immunogenicity of anthrax PA, in the presence and absence of the soluble von Willebrand factor A domain of the human form of receptor capillary morphogenesis protein 2 (sCMG2), to elicit antibodies to PA in BALB/c mice. Prior studies showed that sCMG2 stabilizes the 83-kDa PA structure to pH, chemical denaturants, temperature, and proteolysis and slows the hydrogen-deuterium exchange rate of histidine residues far from the binding interface. In contrast to a vaccine containing PA without adjuvant, we found that mice immunized with PA in stable complex with sCMG2 showed markedly reduced antibody responses to PA, including toxin-neutralizing antibodies and antibodies to domain 4, which correlated with fewer toxin-neutralizing antibodies. In contrast, mice immunized with PA in concert with a nonbinding mutant of sCMG2 (D50A) showed anti-PA antibody responses similar to those observed with PA alone. Our results suggest that addition of sCMG2 to a PA vaccine formulation is likely to result in a significantly diminished immune response, but we discuss the multitude of factors that could contribute to reduced immunogenicity.IMPORTANCE The anthrax toxin PA is the major immunogen in the current anthrax vaccine (anthrax vaccine adsorbed). Improving the anthrax vaccine for avoidance of a cold chain necessitates improvements in the thermodynamic stability of PA. We address how stabilizing PA using sCMG2 affects PA immunogenicity in BALB/c mice. Although the stability of PA is increased by binding to sCMG2, PA immunogenicity is decreased. This study emphasizes that, while binding of a ligand retains or improves conformational stability without affecting the native sequence, epitope recognition or processing may be affected, abrogating an effective immune response.
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Affiliation(s)
- Fabiana Freire Mendes de Oliveira
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | | | - Srinivas Gonti
- Department of Chemistry, Wichita State University, Wichita, Kansas, USA
| | | | - Han Li
- Division of Bacterial Disease, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Jarad Schiffer
- Division of Bacterial Disease, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - James G Bann
- Department of Chemistry, Wichita State University, Wichita, Kansas, USA
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Yang H, Staveness D, Ryckbosch SM, Axtman AD, Loy BA, Barnes AB, Pande VS, Schaefer J, Wender PA, Cegelski L. REDOR NMR Reveals Multiple Conformers for a Protein Kinase C Ligand in a Membrane Environment. ACS Cent Sci 2018; 4:89-96. [PMID: 29392180 PMCID: PMC5785774 DOI: 10.1021/acscentsci.7b00475] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Indexed: 05/05/2023]
Abstract
Bryostatin 1 (henceforth bryostatin) is in clinical trials for the treatment of Alzheimer's disease and for HIV/AIDS eradication. It is also a preclinical lead for cancer immunotherapy and other therapeutic indications. Yet nothing is known about the conformation of bryostatin bound to its protein kinase C (PKC) target in a membrane microenvironment. As a result, efforts to design more efficacious, better tolerated, or more synthetically accessible ligands have been limited to structures that do not include PKC or membrane effects known to influence PKC-ligand binding. This problem extends more generally to many membrane-associated proteins in the human proteome. Here, we use rotational-echo double-resonance (REDOR) solid-state NMR to determine the conformations of PKC modulators bound to the PKCδ-C1b domain in the presence of phospholipid vesicles. The conformationally limited PKC modulator phorbol diacetate (PDAc) is used as an initial test substrate. While unanticipated partitioning of PDAc between an immobilized protein-bound state and a mobile state in the phospholipid assembly was observed, a single conformation in the bound state was identified. In striking contrast, a bryostatin analogue (bryolog) was found to exist exclusively in a protein-bound state, but adopts a distribution of conformations as defined by three independent distance measurements. The detection of multiple PKCδ-C1b-bound bryolog conformers in a functionally relevant phospholipid complex reveals the inherent dynamic nature of cellular systems that is not captured with single-conformation static structures. These results indicate that binding, selectivity, and function of PKC modulators, as well as the design of new modulators, are best addressed using a dynamic multistate model, an analysis potentially applicable to other membrane-associated proteins.
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Affiliation(s)
- Hao Yang
- Department
of Chemistry, Washington University in St.
Louis, St. Louis, Missouri 63130, United
States
| | - Daryl Staveness
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Steven M. Ryckbosch
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Alison D. Axtman
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Brian A. Loy
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Alexander B. Barnes
- Department
of Chemistry, Washington University in St.
Louis, St. Louis, Missouri 63130, United
States
| | - Vijay S. Pande
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jacob Schaefer
- Department
of Chemistry, Washington University in St.
Louis, St. Louis, Missouri 63130, United
States
| | - Paul A. Wender
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
- Department
of Chemical and Systems Biology, Stanford
University, Stanford, California 94305, United States
| | - Lynette Cegelski
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
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Patrick GJ, Fang L, Schaefer J, Singh S, Bowman GR, Wencewicz TA. Mechanistic Basis for ATP-Dependent Inhibition of Glutamine Synthetase by Tabtoxinine-β-lactam. Biochemistry 2018; 57:117-135. [PMID: 29039929 PMCID: PMC5934995 DOI: 10.1021/acs.biochem.7b00838] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Tabtoxinine-β-lactam (TβL), also known as wildfire toxin, is a time- and ATP-dependent inhibitor of glutamine synthetase produced by plant pathogenic strains of Pseudomonas syringae. Here we demonstrate that recombinant glutamine synthetase from Escherichia coli phosphorylates the C3-hydroxyl group of the TβL 3-(S)-hydroxy-β-lactam (3-HβL) warhead. Phosphorylation of TβL generates a stable, noncovalent enzyme-ADP-inhibitor complex that resembles the glutamine synthetase tetrahedral transition state. The TβL β-lactam ring remains intact during enzyme inhibition, making TβL mechanistically distinct from traditional β-lactam antibiotics such as penicillin. Our findings could enable the design of new 3-HβL transition state inhibitors targeting enzymes in the ATP-dependent carboxylate-amine ligase superfamily with broad therapeutic potential in many disease areas.
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Affiliation(s)
- Garrett J. Patrick
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO, 63130, USA
| | - Luting Fang
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO, 63130, USA
| | - Jacob Schaefer
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO, 63130, USA
| | - Sukrit Singh
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
| | - Gregory R. Bowman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
| | - Timothy A. Wencewicz
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO, 63130, USA
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Vosegaard T, Kamihira-Ishijima M, Watts A, Nielsen NC. Helix conformations in 7TM membrane proteins determined using oriented-sample solid-state NMR with multiple residue-specific 15N labeling. Biophys J 2007; 94:241-50. [PMID: 17827220 PMCID: PMC2134869 DOI: 10.1529/biophysj.107.116004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Oriented solid-state NMR in combination with multiple-residue-specific (15)N labeling and extensive numerical spectral analysis is proposed to determine helix conformations of large membrane proteins in native membranes. The method is demonstrated on uniaxially oriented samples of (15)N-methionine, -valine, and -glycine-labeled bacteriorhopsin in native purple membranes. Experimental two-dimensional (1)H-(15)N dipole-dipole coupling versus (15)N chemical shift spectra for all samples are analyzed numerically to establish combined constraints on the orientation of the seven transmembrane helices relative to the membrane bilayer normal. Since the method does not depend on specific resonance assignments and proves robust toward nonidealities in the sample alignment, it may be generally feasible for the study of conformational arrangement and function-induced conformation changes of large integral membrane proteins.
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Affiliation(s)
- Thomas Vosegaard
- Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, University of Aarhus, Aarhus, Denmark.
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Matsuoka S, Schaefer J. Double-quantum filtered rotational-echo double resonance. J Magn Reson 2006; 183:252-8. [PMID: 17008112 DOI: 10.1016/j.jmr.2006.08.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 08/14/2006] [Accepted: 08/15/2006] [Indexed: 05/12/2023]
Abstract
The homonuclear scalar coupling of a directly bonded 13C-13C pair has been used to create a double-quantum filter (DQF) to remove the natural-abundance 13C background in 13C{15N} rotational-echo double-resonance (REDOR) experiments. The DQF scalar and REDOR dipolar evolution periods are coincident which is important for sensitivity in the event of weak 13C-15N dipolar coupling. Calculated and observed 13C{15N} DQF-REDOR dephasings were in agreement for a test sample of mixed recrystallized labeled alanines. Glycine metabolism in a single uniform-15N soybean leaf labeled for 6 min by 13CO2 was measured quantitatively by 13C{15N} DQF-REDOR with no background interferences.
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Affiliation(s)
- Shigeru Matsuoka
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA
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Jiang YL, McDowell LM, Poliks B, Studelska DR, Cao C, Potter GS, Schaefer J, Song F, Stivers JT. Recognition of an unnatural difluorophenyl nucleotide by uracil DNA glycosylase. Biochemistry 2005; 43:15429-38. [PMID: 15581354 DOI: 10.1021/bi0483864] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The DNA repair enzyme uracil DNA glycosylase (UDG) utilizes base flipping to recognize and remove unwanted uracil bases from the genome but does not react with its structural congener, thymine, which differs by a single methyl group. Two factors that determine whether an enzyme flips a base from the duplex are its shape and hydrogen bonding properties. To probe the role of these factors in uracil recognition by UDG, we have synthesized a DNA duplex that contains a single difluorophenyl (F) nucleotide analogue that is an excellent isostere of uracil but possesses no hydrogen bond donor or acceptor groups. By using binding affinity measurements, solution (19)F NMR, and solid state (31)P[(19)F] rotational-echo double-resonance (REDOR) NMR measurements, we establish that UDG partially unstacks F from the duplex. However, due to the lack of hydrogen bonding groups that are required to support an open-to-closed conformational transition in UDG, F cannot stably dock in the UDG active site. We propose that F attains a metastable unstacked state that mimics a previously detected intermediate on the uracil-flipping pathway and suggest structural models of the metastable state that are consistent with the REDOR NMR measurements.
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Affiliation(s)
- Yu Lin Jiang
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205-2185, USA
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Sinha N, Schmidt-Rohr K, Hong M. Compensation for pulse imperfections in rotational-echo double-resonance NMR by composite pulses and EXORCYCLE. J Magn Reson 2004; 168:358-365. [PMID: 15140448 DOI: 10.1016/j.jmr.2004.03.025] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2004] [Revised: 03/02/2004] [Indexed: 05/24/2023]
Abstract
We describe a simple method to compensate for pulse-angle errors in rotational-echo double resonance (REDOR) experiments for determining heteronuclear distances in solids. By using composite 180 degrees pulses on the unobserved dephasing spin and EXORCYCLE for the single pi pulse on the observed channel, the REDOR curve becomes much less sensitive to pulse-angle errors. Both improvements are demonstrated by experiments on the model compound, (15)N, (13)Calpha -labeled N-t-BOC-glycine, and are confirmed by numerical simulations. The advantage of EXORCYCLE is also shown analytically using the product operator formalism. The proposed simple schemes compensate for unavoidable pulse-angle errors that arise, for example, from radiofrequency field inhomogeneity. They also make REDOR experiments more accurate and robust for low-sensitivity samples where direct pulse-length calibration is difficult.
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Affiliation(s)
- Neeraj Sinha
- Department of Chemistry, Iowa State University, Ames, IA 50011, USA
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Abstract
Rotational-echo double resonance (REDOR) is a magic-angle spinning technique for measuring heteronuclear dipolar couplings. Rotor-synchronized pi pulses recouple the dipolar interaction. The accuracy of a REDOR determination of distance or orientation depends totally on the quality of the dephased (recoupled) and full-echo spectra. We present a scheme for measuring and compensating for the effects of pulse imperfections in REDOR experiments. No assumptions are made about the quality of the pi pulses, and no pulses are added or taken away in implementing the compensation for incomplete REDOR dephasing by imperfect pi pulses.
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