1
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Kalabekova R, Quinn CM, Movellan KT, Gronenborn AM, Akke M, Polenova T. 19F Fast Magic-Angle Spinning NMR Spectroscopy on Microcrystalline Complexes of Fluorinated Ligands and the Carbohydrate Recognition Domain of Galectin-3. Biochemistry 2024; 63:2207-2216. [PMID: 39008798 DOI: 10.1021/acs.biochem.4c00232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
Structural characterization of protein-ligand binding interfaces at atomic resolution is essential for improving the design of specific and potent inhibitors. Herein, we explored fast 19F- and 1H-detected magic angle spinning NMR spectroscopy to investigate the interaction between two fluorinated ligand diastereomers with the microcrystalline galectin-3 carbohydrate recognition domain. The detailed environment around the fluorine atoms was mapped by 2D 13C-19F and 1H-19F dipolar correlation experiments and permitted characterization of the binding interface. Our results demonstrate that 19F MAS NMR is a powerful tool for detailed characterization of protein-ligand interfaces and protein interactions at the atomic level.
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Affiliation(s)
- Roza Kalabekova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Caitlin M Quinn
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Kumar Tekwani Movellan
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Angela M Gronenborn
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Ave., Pittsburgh, Pennsylvania 15261, United States
| | - Mikael Akke
- Division of Biophysical Chemistry, Center for Molecular Protein Science, Department of Chemistry, Lund University, P.O. Box 124, Lund SE-22100, Sweden
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Ave., Pittsburgh, Pennsylvania 15261, United States
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2
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Porat-Dahlerbruch G, Struppe J, Quinn CM, Gronenborn AM, Polenova T. 19F fast MAS (60-111 kHz) dipolar and scalar based correlation spectroscopy of organic molecules and pharmaceutical formulations. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2022; 122:101831. [PMID: 36182713 DOI: 10.1016/j.ssnmr.2022.101831] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 06/16/2023]
Abstract
19F magic angle spinning (MAS) NMR spectroscopy is a powerful tool for characterization of fluorinated solids. The recent development of 19F MAS NMR probes, operating at spinning frequencies of 60-111 kHz, enabled analysis of systems spanning from organic molecules to pharmaceutical formulations to biological assemblies, with unprecedented resolution. Herein, we systematically evaluate the benefits of high MAS frequencies (60-111 kHz) for 1D and 2D 19F-detected experiments in two pharmaceuticals, the antimalarial drug mefloquine and a formulation of the cholesterol-lowering drug atorvastatin calcium. We demonstrate that 1H decoupling is essential and that scalar-based, heteronuclear single quantum coherence (HSQC) and heteronuclear multiple quantum coherence (HMQC) correlation experiments become feasible and efficient at the MAS frequency of 100 kHz. This study opens doors for the applications of high frequency 19F MAS NMR to a wide range of problems in chemistry and biology.
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Affiliation(s)
- Gal Porat-Dahlerbruch
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States
| | - Jochem Struppe
- Bruker Biospin Corporation, 15 Fortune Drive, Billerica, MA, 01821, United States
| | - Caitlin M Quinn
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States
| | - Angela M Gronenborn
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States; Department of Structural Biology, University of Pittsburgh, School of Medicine, 3501 Fifth Ave., Pittsburgh, PA, 15261, United States; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA, 15261, United States
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States; Department of Structural Biology, University of Pittsburgh, School of Medicine, 3501 Fifth Ave., Pittsburgh, PA, 15261, United States; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA, 15261, United States.
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3
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Duan P, Dregni AJ, Hong M. Solid-State NMR 19F- 1H- 15N Correlation Experiments for Resonance Assignment and Distance Measurements of Multifluorinated Proteins. J Phys Chem A 2022; 126:7021-7032. [PMID: 36150071 PMCID: PMC10867861 DOI: 10.1021/acs.jpca.2c05154] [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] [Indexed: 11/28/2022]
Abstract
Several solid-state NMR techniques have been introduced recently to measure nanometer distances involving 19F, whose high gyromagnetic ratio makes it a potent nuclear spin for structural investigation. These solid-state NMR techniques either use 19F correlation with 1H or 13C to obtain qualitative interatomic contacts or use the rotational-echo double-resonance (REDOR) pulse sequence to measure quantitative distances. However, no NMR technique is yet available for disambiguating 1H-19F distances in multiply fluorinated proteins and protein-ligand complexes. Here, we introduce a three-dimensional (3D) 19F-15N-1H correlation experiment that resolves the distances of multiple fluorines to their adjacent amide protons. We show that optimal polarization transfer between 1H and 19F spins is achieved using an out-and-back 1H-19F REDOR sequence. We demonstrate this 3D correlation experiment on the model protein GB1 and apply it to the multidrug-resistance transporter, EmrE, complexed to a tetrafluorinated substrate. This technique should be useful for resolving and assigning distance constraints in multiply fluorinated proteins, leading to significant savings of time and precious samples compared to producing several singly fluorinated samples. Moreover, the method enables structural determination of protein-ligand complexes for ligands that contain multiple fluorines.
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Affiliation(s)
- Pu Duan
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Aurelio J. Dregni
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
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4
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Du Y, Su Y. 19F Solid-state NMR characterization of pharmaceutical solids. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2022; 120:101796. [PMID: 35688018 DOI: 10.1016/j.ssnmr.2022.101796] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 05/18/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Solid-state NMR has been increasingly recognized as a high-resolution and versatile spectroscopic tool to characterize drug substances and products. However, the analysis of pharmaceutical materials is often carried out at natural isotopic abundance and a relatively low drug loading in multi-component systems and therefore suffers from challenges of low sensitivity. The fact that fluorinated therapeutics are well represented in pipeline drugs and commercial products offers an excellent opportunity to utilize fluorine as a molecular probe for pharmaceutical analysis. We aim to review recent advancements of 19F magic angle spinning NMR methods in modern drug research and development. Applications to polymorph screening at the micromolar level, structural elucidation, and investigation of molecular interactions at the Ångström to submicron resolution in drug delivery, stability, and quality will be discussed.
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Affiliation(s)
- Yong Du
- Analytical Research and Development, Merck & Co., Inc., Rahway, NJ, 07065, United States
| | - Yongchao Su
- Analytical Research and Development, Merck & Co., Inc., Rahway, NJ, 07065, United States; Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, IN, 47907, United States; Division of Molecular Pharmaceutics and Drug Delivery, College of Pharmacy, The University of Texas at Austin, Austin, TX, 78712, United States; Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, CT, 06269, United States.
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5
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Duan P, Chen KJ, Wijegunawardena G, Dregni AJ, Wang HK, Wu H, Hong M. Binding Sites of a Positron Emission Tomography Imaging Agent in Alzheimer's β-Amyloid Fibrils Studied Using 19F Solid-State NMR. J Am Chem Soc 2022; 144:1416-1430. [PMID: 35015530 PMCID: PMC8855532 DOI: 10.1021/jacs.1c12056] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Amyloid imaging by positron emission tomography (PET) is an important method for diagnosing neurodegenerative disorders such as Alzheimer's disease. Many 11C- and 18F-labeled PET tracers show varying binding capacities, specificities, and affinities for their target proteins. The structural basis of these variations is poorly understood. Here we employ 19F and 13C solid-state NMR to investigate the binding sites of a PET ligand, flutemetamol, to the 40-residue Alzheimer's β-amyloid peptide (Aβ40). Analytical high-performance liquid chromatography and 19F NMR spectra show that flutemetamol binds the current Aβ40 fibril polymorph with a stoichiometry of one ligand per four to five peptides. Half of the ligands are tightly bound while the other half are loosely bound. 13C and 15N chemical shifts indicate that this Aβ40 polymorph has an immobilized N-terminus, a non-β-sheet His14, and a non-β-sheet C-terminus. We measured the proximity of the ligand fluorine to peptide residues using 19F-13C and 19F-1H rotational-echo double-resonance (REDOR) experiments. The spectra show that three segments in the peptide, 12VHH14, 18VFF20, and 39VV40, lie the closest to the ligand. REDOR-constrained docking simulations indicate that these three segments form multiple binding sites, and the ligand orientations and positions at these sites are similar across different Aβ polymorphs. Comparison of the flutemetamol-interacting residues in Aβ40 with the small-molecule binding sites in other amyloid proteins suggest that conjugated aromatic compounds preferentially bind β-sheet surface grooves lined by aromatic, polar, and charged residues. These motifs may explain the specificity of different PET tracers to different amyloid proteins.
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Affiliation(s)
- Pu Duan
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States
| | - Kelly J. Chen
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States
| | - Gayani Wijegunawardena
- Department of Chemistry and Biochemistry, Wichita State University, 1845 Fairmount St, Wichita, KS 67260, United States
| | - Aurelio J. Dregni
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States
| | - Harrison K. Wang
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States
| | - Haifan Wu
- Department of Chemistry and Biochemistry, Wichita State University, 1845 Fairmount St, Wichita, KS 67260, United States
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States
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6
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Klein A, Rovó P, Sakhrani VV, Wang Y, Holmes JB, Liu V, Skowronek P, Kukuk L, Vasa SK, Güntert P, Mueller LJ, Linser R. Atomic-resolution chemical characterization of (2x)72-kDa tryptophan synthase via four- and five-dimensional 1H-detected solid-state NMR. Proc Natl Acad Sci U S A 2022; 119:e2114690119. [PMID: 35058365 PMCID: PMC8795498 DOI: 10.1073/pnas.2114690119] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 12/13/2021] [Indexed: 02/07/2023] Open
Abstract
NMR chemical shifts provide detailed information on the chemical properties of molecules, thereby complementing structural data from techniques like X-ray crystallography and electron microscopy. Detailed analysis of protein NMR data, however, often hinges on comprehensive, site-specific assignment of backbone resonances, which becomes a bottleneck for molecular weights beyond 40 to 45 kDa. Here, we show that assignments for the (2x)72-kDa protein tryptophan synthase (665 amino acids per asymmetric unit) can be achieved via higher-dimensional, proton-detected, solid-state NMR using a single, 1-mg, uniformly labeled, microcrystalline sample. This framework grants access to atom-specific characterization of chemical properties and relaxation for the backbone and side chains, including those residues important for the catalytic turnover. Combined with first-principles calculations, the chemical shifts in the β-subunit active site suggest a connection between active-site chemistry, the electrostatic environment, and catalytically important dynamics of the portal to the β-subunit from solution.
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Affiliation(s)
- Alexander Klein
- Department of Chemistry and Pharmacy, Ludwig Maximilians University, 81377 Munich, Germany
- Department of Chemistry and Chemical Biology, TU Dortmund University, 44227 Dortmund, Germany
| | - Petra Rovó
- Department of Chemistry and Pharmacy, Ludwig Maximilians University, 81377 Munich, Germany
| | - Varun V Sakhrani
- Department of Chemistry, University of California, Riverside, CA 92521
| | - Yangyang Wang
- Department of Chemistry, University of California, Riverside, CA 92521
| | - Jacob B Holmes
- Department of Chemistry, University of California, Riverside, CA 92521
| | - Viktoriia Liu
- Department of Chemistry, University of California, Riverside, CA 92521
| | - Patricia Skowronek
- Department of Chemistry and Pharmacy, Ludwig Maximilians University, 81377 Munich, Germany
| | - Laura Kukuk
- Department of Chemistry and Chemical Biology, TU Dortmund University, 44227 Dortmund, Germany
| | - Suresh K Vasa
- Department of Chemistry and Pharmacy, Ludwig Maximilians University, 81377 Munich, Germany
- Department of Chemistry and Chemical Biology, TU Dortmund University, 44227 Dortmund, Germany
| | - Peter Güntert
- Institute of Biophysical Chemistry, Goethe University, 60438 Frankfurt am Main, Germany
- Laboratory of Physical Chemistry, Eidgenössische Technische Hochschule (ETH) Zürich, 8093 Zürich, Switzerland
- Department of Chemistry, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Leonard J Mueller
- Department of Chemistry, University of California, Riverside, CA 92521
| | - Rasmus Linser
- Department of Chemistry and Pharmacy, Ludwig Maximilians University, 81377 Munich, Germany;
- Department of Chemistry and Chemical Biology, TU Dortmund University, 44227 Dortmund, Germany
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7
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Ghassemi N, Poulhazan A, Deligey F, Mentink-Vigier F, Marcotte I, Wang T. Solid-State NMR Investigations of Extracellular Matrixes and Cell Walls of Algae, Bacteria, Fungi, and Plants. Chem Rev 2021; 122:10036-10086. [PMID: 34878762 DOI: 10.1021/acs.chemrev.1c00669] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Extracellular matrixes (ECMs), such as the cell walls and biofilms, are important for supporting cell integrity and function and regulating intercellular communication. These biomaterials are also of significant interest to the production of biofuels and the development of antimicrobial treatment. Solid-state nuclear magnetic resonance (ssNMR) and magic-angle spinning-dynamic nuclear polarization (MAS-DNP) are uniquely powerful for understanding the conformational structure, dynamical characteristics, and supramolecular assemblies of carbohydrates and other biomolecules in ECMs. This review highlights the recent high-resolution investigations of intact ECMs and native cells in many organisms spanning across plants, bacteria, fungi, and algae. We spotlight the structural principles identified in ECMs, discuss the current technical limitation and underexplored biochemical topics, and point out the promising opportunities enabled by the recent advances of the rapidly evolving ssNMR technology.
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Affiliation(s)
- Nader Ghassemi
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Alexandre Poulhazan
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.,Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Fabien Deligey
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | | | - Isabelle Marcotte
- Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Tuo Wang
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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8
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Shcherbakov AA, Medeiros-Silva J, Tran N, Gelenter MD, Hong M. From Angstroms to Nanometers: Measuring Interatomic Distances by Solid-State NMR. Chem Rev 2021; 122:9848-9879. [PMID: 34694769 DOI: 10.1021/acs.chemrev.1c00662] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Internuclear distances represent one of the main structural constraints in molecular structure determination using solid-state NMR spectroscopy, complementing chemical shifts and orientational restraints. Although a large number of magic-angle-spinning (MAS) NMR techniques have been available for distance measurements, traditional 13C and 15N NMR experiments are inherently limited to distances of a few angstroms due to the low gyromagnetic ratios of these nuclei. Recent development of fast MAS triple-resonance 19F and 1H NMR probes has stimulated the design of MAS NMR experiments that measure distances in the 1-2 nm range with high sensitivity. This review describes the principles and applications of these multiplexed multidimensional correlation distance NMR experiments, with an emphasis on 19F- and 1H-based distance experiments. Representative applications of these long-distance NMR methods to biological macromolecules as well as small molecules are reviewed.
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Affiliation(s)
- Alexander A Shcherbakov
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States
| | - João Medeiros-Silva
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States
| | - Nhi Tran
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States
| | - Martin D Gelenter
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States
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9
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Guo C, Fritz MP, Struppe J, Wegner S, Stringer J, Sergeyev IV, Quinn CM, Gronenborn AM, Polenova T. Fast 19F Magic Angle Spinning NMR Crystallography for Structural Characterization of Fluorine-Containing Pharmaceutical Compounds. Anal Chem 2021; 93:8210-8218. [PMID: 34080855 DOI: 10.1021/acs.analchem.1c00784] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Fluorine-containing compounds comprise 20 to 30 percent of all commercial drugs, and the proportion of fluorinated pharmaceuticals is rapidly growing. While magic angle spinning (MAS) NMR spectroscopy is a popular technique for analysis of solid pharmaceutical compounds, fluorine has been underutilized as a structural probe so far. Here, we report a fast (40-60 kHz) MAS 19F NMR approach for structural characterization of fluorine-containing crystalline pharmaceutical compounds at natural abundance, using the antimalarial fluorine-containing drug mefloquine as an example. We demonstrate the utility of 2D 19F-13C and 19F-19F dipolar-coupling-based correlation experiments for 19F and 13C resonance frequency assignment, which permit identification of crystallographically inequivalent sites. The efficiency of 19F-13C cross-polarization and the effect of 1H and 19F decoupling on spectral resolution and sensitivity were evaluated in a broad range of experimental conditions. We further demonstrate a protocol for measuring accurate interfluorine distances based on 1D DANTE-RFDR experiments combined with multispin numerical simulations.
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Affiliation(s)
- Changmiao Guo
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States.,Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, Pennsylvania 15261, United States
| | - Matthew P Fritz
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States.,Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, Pennsylvania 15261, United States
| | - Jochem Struppe
- Bruker Biospin Corporation, 15 Fortune Drive, Billerica, Massachusetts 01821, United States
| | | | - John Stringer
- PhoenixNMR, 510 E. 5th Street, Loveland, Colorado 80537, United States
| | - Ivan V Sergeyev
- Bruker Biospin Corporation, 15 Fortune Drive, Billerica, Massachusetts 01821, United States
| | - Caitlin M Quinn
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Angela M Gronenborn
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, Pennsylvania 15261, United States.,Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, Pennsylvania 15261, United States
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States.,Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, Pennsylvania 15261, United States
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10
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Reif B, Ashbrook SE, Emsley L, Hong M. Solid-state NMR spectroscopy. NATURE REVIEWS. METHODS PRIMERS 2021; 1:2. [PMID: 34368784 PMCID: PMC8341432 DOI: 10.1038/s43586-020-00002-1] [Citation(s) in RCA: 182] [Impact Index Per Article: 60.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/29/2020] [Indexed: 12/18/2022]
Abstract
Solid-state nuclear magnetic resonance (NMR) spectroscopy is an atomic-level method used to determine the chemical structure, three-dimensional structure, and dynamics of solids and semi-solids. This Primer summarizes the basic principles of NMR as applied to the wide range of solid systems. The fundamental nuclear spin interactions and the effects of magnetic fields and radiofrequency pulses on nuclear spins are the same as in liquid-state NMR. However, because of the anisotropy of the interactions in the solid state, the majority of high-resolution solid-state NMR spectra is measured under magic-angle spinning (MAS), which has profound effects on the types of radiofrequency pulse sequences required to extract structural and dynamical information. We describe the most common MAS NMR experiments and data analysis approaches for investigating biological macromolecules, organic materials, and inorganic solids. Continuing development of sensitivity-enhancement approaches, including 1H-detected fast MAS experiments, dynamic nuclear polarization, and experiments tailored to ultrahigh magnetic fields, is described. We highlight recent applications of solid-state NMR to biological and materials chemistry. The Primer ends with a discussion of current limitations of NMR to study solids, and points to future avenues of development to further enhance the capabilities of this sophisticated spectroscopy for new applications.
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Affiliation(s)
- Bernd Reif
- Technische Universität München, Department Chemie, Lichtenbergstr. 4, D-85747 Garching, Germany
| | - Sharon E. Ashbrook
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, UK
| | - Lyndon Emsley
- École Polytechnique Fédérale de Lausanne (EPFL), Institut des sciences et ingénierie chimiques, CH-1015 Lausanne, Switzerland
| | - Mei Hong
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
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11
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Shcherbakov AA, Roos M, Kwon B, Hong M. Two-dimensional 19F- 13C correlation NMR for 19F resonance assignment of fluorinated proteins. JOURNAL OF BIOMOLECULAR NMR 2020; 74:193-204. [PMID: 32088840 PMCID: PMC7445029 DOI: 10.1007/s10858-020-00306-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 02/13/2020] [Indexed: 05/09/2023]
Abstract
19F solid-state NMR is an excellent approach for measuring long-range distances for structure determination and for studying molecular motion. For multi-fluorinated proteins, assignment of 19F chemical shifts has been traditionally carried out using mutagenesis. Here we show 2D 19F-13C correlation experiments that allow efficient assignment of the 19F chemical shifts. We have compared several rotational-echo double-resonance-based pulse sequences and 19F-13C cross polarization (CP) for 2D 19F-13C correlation. We found that direct transferred-echo double-resonance (TEDOR) transfer from 19F to 13C and vice versa outperforms out-and-back coherence transfer schemes. 19F detection gives twofold higher sensitivity over 13C detection for the 2D correlation experiment. At MAS frequencies of 25-35 kHz, double-quantum 19F-13C CP has higher coherence transfer efficiencies than zero-quantum CP. The most efficient TEDOR transfer experiment has higher sensitivity than the most efficient double-quantum CP experiment. We demonstrate these 2D 19F-13C correlation experiments on the model compounds t-Boc-4F-phenylalanine and GB1. Application of the 2D 19F-13C TEDOR correlation experiment to the tetrameric influenza BM2 transmembrane peptide shows intermolecular 13C-19F cross peaks that indicate that the BM2 tetramers cluster in the lipid bilayer in an antiparallel fashion. This clustering may be relevant for the virus budding function of this protein.
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Affiliation(s)
- Alexander A Shcherbakov
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA, 02139, USA
| | - Matthias Roos
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA, 02139, USA
| | - Byungsu Kwon
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA, 02139, USA
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA, 02139, USA.
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12
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Fritz M, Kraus J, Quinn CM, Yap GPA, Struppe J, Sergeyev IV, Gronenborn AM, Polenova T. Measurement of Accurate Interfluorine Distances in Crystalline Organic Solids: A High-Frequency Magic Angle Spinning NMR Approach. J Phys Chem B 2019; 123:10680-10690. [PMID: 31682453 DOI: 10.1021/acs.jpcb.9b08919] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Long-range interatomic distance restraints are critical for the determination of molecular structures by NMR spectroscopy, both in solution and in the solid state. Fluorine is a powerful NMR probe in a wide variety of contexts, owing to its favorable magnetic properties, ease of incorporation into biological molecules, and ubiquitous use in synthetic organic molecules designed for diverse applications. Because of the large gyromagnetic ratio of the 100% naturally abundant 19F isotope, interfluorine distances as long as 20 Å are accessible in magic-angle spinning (MAS) dipolar recoupling experiments. Herein, we present an approach for the determination of accurate interfluorine distances in multispin systems, using the finite pulse radio frequency driven recoupling (fpRFDR) at high MAS frequencies of 40-60 kHz. We use a series of crystalline "molecular ruler" solids, difluorobenzoic acids and 7F-L-tryptophan, for which the intra- and intermolecular interfluorine distances are known. We describe the optimal experimental conditions for accurate distance determinations, including the choice of a phase cycle, the relative advantages of selective inversion one-dimensional versus two-dimensional correlation experiments, and the appropriate numerical simulation protocols. An optimal strategy for the analysis of RFDR exchange curves in organic solids with extended spin interaction networks is presented, which, even in the absence of crystal structures, can be potentially incorporated into NMR structure determination.
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Affiliation(s)
- Matthew Fritz
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States.,Pittsburgh Center for HIV Protein Interactions , University of Pittsburgh School of Medicine , 1051 Biomedical Science Tower 3, 3501 Fifth Avenue , Pittsburgh , Pennsylvania 15261 , United States
| | - Jodi Kraus
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States.,Pittsburgh Center for HIV Protein Interactions , University of Pittsburgh School of Medicine , 1051 Biomedical Science Tower 3, 3501 Fifth Avenue , Pittsburgh , Pennsylvania 15261 , United States
| | - Caitlin M Quinn
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Glenn P A Yap
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Jochem Struppe
- Bruker Biospin Corporation , 15 Fortune Drive , Billerica , Massachusetts 01821 , United States
| | - Ivan V Sergeyev
- Bruker Biospin Corporation , 15 Fortune Drive , Billerica , Massachusetts 01821 , United States
| | - Angela M Gronenborn
- Pittsburgh Center for HIV Protein Interactions , University of Pittsburgh School of Medicine , 1051 Biomedical Science Tower 3, 3501 Fifth Avenue , Pittsburgh , Pennsylvania 15261 , United States.,Department of Structural Biology , University of Pittsburgh School of Medicine , 3501 Fifth Avenue , Pittsburgh , Pennsylvania 15261 , United States
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States.,Pittsburgh Center for HIV Protein Interactions , University of Pittsburgh School of Medicine , 1051 Biomedical Science Tower 3, 3501 Fifth Avenue , Pittsburgh , Pennsylvania 15261 , United States
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13
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Salnikov ES, De Zotti M, Bobone S, Mazzuca C, Raya J, Siano AS, Peggion C, Toniolo C, Stella L, Bechinger B. Trichogin GA IV Alignment and Oligomerization in Phospholipid Bilayers. Chembiochem 2019; 20:2141-2150. [PMID: 31125169 DOI: 10.1002/cbic.201900263] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Indexed: 12/21/2022]
Abstract
Trichogin GA IV is a short peptaibol with antimicrobial activity. This uncharged, but amphipathic, sequence is aligned at the membrane interface and undergoes a transition to an aggregated state that inserts more deeply into the membrane, an assembly that predominates at a peptide-to-lipid ratio (P/L) of 1:20. In this work, the natural trichogin sequence was prepared and reconstituted into oriented lipid bilayers. The 15 N NMR chemical shift is indicative of a well-defined alignment of the peptide parallel to the membrane surface at P/Ls of 1:120 and 1:20. When the P/L is increased to 1:8, an additional peptide topology is observed that is indicative of a heterogeneous orientation, with helix alignments ranging from around the magic angle to perfectly in-plane. The topological preference of the trichogin helix for an orientation parallel to the membrane surface was confirmed by attenuated total reflection FTIR spectroscopy. Furthermore, 19 F CODEX experiments were performed on a trichogin sequence with 19 F-Phe at position 10. The CODEX decay is in agreement with a tetrameric complex, in which the 19 F sites are about 9-9.5 Å apart. Thus, a model emerges in which the monomeric peptide aligns along the membrane surface. When the peptide concentration increases, first dimeric and then tetrameric assemblies form, made up from helices oriented predominantly parallel to the membrane surface. The formation of these aggregates correlates with the release of vesicle contents including relatively large molecules.
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Affiliation(s)
- Evgeniy S Salnikov
- Institut de Chimie, University of Strasbourg, CNRS, UMR 7177, 4, rue Blaise Pascal, 67070, Strasbourg, France
| | - Marta De Zotti
- ICB, Padova Unit, CNR', Department of Chemistry, University of Padova, via Marzolo 1, 35131, Padova, Italy
| | - Sara Bobone
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Claudia Mazzuca
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Jesus Raya
- Institut de Chimie, University of Strasbourg, CNRS, UMR 7177, 4, rue Blaise Pascal, 67070, Strasbourg, France
| | - Alvaro S Siano
- Departamento de Química Organica, Facultad de Bioquímica y Ciencias Biologicas, Universidad Nacional del Litoral, Ciudad Universitaria UNL, Ruta Nacional N° 168, Km 472, Santa Fe, 3000, Argentina
| | - Cristina Peggion
- ICB, Padova Unit, CNR', Department of Chemistry, University of Padova, via Marzolo 1, 35131, Padova, Italy
| | - Claudio Toniolo
- ICB, Padova Unit, CNR', Department of Chemistry, University of Padova, via Marzolo 1, 35131, Padova, Italy
| | - Lorenzo Stella
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Burkhard Bechinger
- Institut de Chimie, University of Strasbourg, CNRS, UMR 7177, 4, rue Blaise Pascal, 67070, Strasbourg, France
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14
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Lu X, Skomski D, Thompson KC, McNevin MJ, Xu W, Su Y. Three-Dimensional NMR Spectroscopy of Fluorinated Pharmaceutical Solids under Ultrafast Magic Angle Spinning. Anal Chem 2019; 91:6217-6224. [DOI: 10.1021/acs.analchem.9b00884] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Xingyu Lu
- Merck Research Laboratories (MRLs), Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Daniel Skomski
- Merck Research Laboratories (MRLs), Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Karen C. Thompson
- Merck Research Laboratories (MRLs), Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Michael J. McNevin
- Merck Research Laboratories (MRLs), Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Wei Xu
- Merck Research Laboratories (MRLs), Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Yongchao Su
- Merck Research Laboratories (MRLs), Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
- Division of Molecular Pharmaceutics and Drug Delivery, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, United States
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15
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Wang M, Lu M, Fritz MP, Quinn CM, Byeon IJL, Byeon CH, Struppe J, Maas W, Gronenborn AM, Polenova T. Fast Magic-Angle Spinning 19 F NMR Spectroscopy of HIV-1 Capsid Protein Assemblies. Angew Chem Int Ed Engl 2018; 57:16375-16379. [PMID: 30225969 PMCID: PMC6279522 DOI: 10.1002/anie.201809060] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Indexed: 01/18/2023]
Abstract
19 F NMR spectroscopy is an attractive and growing area of research with broad applications in biochemistry, chemical biology, medicinal chemistry, and materials science. We have explored fast magic angle spinning (MAS) 19 F solid-state NMR spectroscopy in assemblies of HIV-1 capsid protein. Tryptophan residues with fluorine substitution at the 5-position of the indole ring were used as the reporters. The 19 F chemical shifts for the five tryptophan residues are distinct, reflecting differences in their local environment. Spin-diffusion and radio-frequency-driven-recoupling experiments were performed at MAS frequencies of 35 kHz and 40-60 kHz, respectively. Fast MAS frequencies of 40-60 kHz are essential for consistently establishing 19 F-19 F correlations, yielding interatomic distances of the order of 20 Å. Our results demonstrate the potential of fast MAS 19 F NMR spectroscopy for structural analysis in large biological assemblies.
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Affiliation(s)
- Mingzhang Wang
- Department of Chemistry and Biochemistry, University of Delaware, Brown Laboratories; Newark, DE 19716, United States,
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States,
| | - Manman Lu
- Department of Chemistry and Biochemistry, University of Delaware, Brown Laboratories; Newark, DE 19716, United States,
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States,
- Department of Structural Biology, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Matthew P. Fritz
- Department of Chemistry and Biochemistry, University of Delaware, Brown Laboratories; Newark, DE 19716, United States,
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States,
| | - Caitlin M. Quinn
- Department of Chemistry and Biochemistry, University of Delaware, Brown Laboratories; Newark, DE 19716, United States,
| | - In-Ja L. Byeon
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States,
- Department of Structural Biology, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Chang-Hyeock Byeon
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States,
- Department of Structural Biology, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Jochem Struppe
- Bruker Biospin Corporation, 15 Fortune Drive, Billerica, MA, United States
| | - Werner Maas
- Bruker Biospin Corporation, 15 Fortune Drive, Billerica, MA, United States
| | - Angela M. Gronenborn
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States,
- Department of Structural Biology, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, Brown Laboratories; Newark, DE 19716, United States,
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States,
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16
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Wang M, Lu M, Fritz MP, Quinn CM, Byeon IL, Byeon C, Struppe J, Maas W, Gronenborn AM, Polenova T. Fast Magic‐Angle Spinning
19
F NMR Spectroscopy of HIV‐1 Capsid Protein Assemblies. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201809060] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Mingzhang Wang
- Department of Chemistry and Biochemistry University of Delaware Brown Laboratories Newark DE 19716 USA
- Pittsburgh Center for HIV Protein Interactions University of Pittsburgh School of Medicine 1051 Biomedical Science Tower 3, 3501 Fifth Avenue Pittsburgh PA 15261 USA
| | - Manman Lu
- Department of Chemistry and Biochemistry University of Delaware Brown Laboratories Newark DE 19716 USA
- Pittsburgh Center for HIV Protein Interactions University of Pittsburgh School of Medicine 1051 Biomedical Science Tower 3, 3501 Fifth Avenue Pittsburgh PA 15261 USA
- Department of Structural Biology University of Pittsburgh School of Medicine 1051 Biomedical Science Tower 3, 3501 Fifth Avenue Pittsburgh PA 15261 USA
| | - Matthew P. Fritz
- Department of Chemistry and Biochemistry University of Delaware Brown Laboratories Newark DE 19716 USA
- Pittsburgh Center for HIV Protein Interactions University of Pittsburgh School of Medicine 1051 Biomedical Science Tower 3, 3501 Fifth Avenue Pittsburgh PA 15261 USA
| | - Caitlin M. Quinn
- Department of Chemistry and Biochemistry University of Delaware Brown Laboratories Newark DE 19716 USA
| | - In‐Ja L. Byeon
- Pittsburgh Center for HIV Protein Interactions University of Pittsburgh School of Medicine 1051 Biomedical Science Tower 3, 3501 Fifth Avenue Pittsburgh PA 15261 USA
- Department of Structural Biology University of Pittsburgh School of Medicine 1051 Biomedical Science Tower 3, 3501 Fifth Avenue Pittsburgh PA 15261 USA
| | - Chang‐Hyeock Byeon
- Pittsburgh Center for HIV Protein Interactions University of Pittsburgh School of Medicine 1051 Biomedical Science Tower 3, 3501 Fifth Avenue Pittsburgh PA 15261 USA
- Department of Structural Biology University of Pittsburgh School of Medicine 1051 Biomedical Science Tower 3, 3501 Fifth Avenue Pittsburgh PA 15261 USA
| | - Jochem Struppe
- Bruker Biospin Corporation 15 Fortune Drive Billerica MA USA
| | - Werner Maas
- Bruker Biospin Corporation 15 Fortune Drive Billerica MA USA
| | - Angela M. Gronenborn
- Pittsburgh Center for HIV Protein Interactions University of Pittsburgh School of Medicine 1051 Biomedical Science Tower 3, 3501 Fifth Avenue Pittsburgh PA 15261 USA
- Department of Structural Biology University of Pittsburgh School of Medicine 1051 Biomedical Science Tower 3, 3501 Fifth Avenue Pittsburgh PA 15261 USA
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry University of Delaware Brown Laboratories Newark DE 19716 USA
- Pittsburgh Center for HIV Protein Interactions University of Pittsburgh School of Medicine 1051 Biomedical Science Tower 3, 3501 Fifth Avenue Pittsburgh PA 15261 USA
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17
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Roos M, Mandala VS, Hong M. Determination of Long-Range Distances by Fast Magic-Angle-Spinning Radiofrequency-Driven 19F- 19F Dipolar Recoupling NMR. J Phys Chem B 2018; 122:9302-9313. [PMID: 30211552 DOI: 10.1021/acs.jpcb.8b06878] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nanometer-range distances are important for restraining the three-dimensional structure and oligomeric assembly of proteins and other biological molecules. Solid-state NMR determination of protein structures typically utilizes 13C-13C and 13C-15N distance restraints, which can only be measured up to ∼7 Å because of the low gyromagnetic ratios of these nuclear spins. To extend the distance reach of NMR, one can harvest the power of 19F, whose large gyromagnetic ratio in principle allows distances up to 2 nm to be measured. However, 19F possesses large chemical shift anisotropies (CSAs) as well as large isotropic chemical shift dispersions, which pose challenges to dipolar coupling measurements. Here, we demonstrate 19F-19F distance measurements at high magnetic fields under fast magic-angle spinning (MAS) using radiofrequency-driven dipolar recoupling (RFDR). We show that 19F-19F cross-peaks for distances up to 1 nm can be readily observed in two-dimensional 19F-19F correlation spectra using less than 5 ms of RFDR mixing. This efficient 19F-19F dipolar recoupling is achieved using practically accessible MAS frequencies of 15-55 kHz, moderate 19F radio frequency field strengths, and no 1H decoupling. Experiments and simulations show that the fastest polarization transfer for aromatic fluorines with the highest distance accuracy is achieved using either fast MAS (e.g., 60 kHz) with large pulse duty cycles (>50%) or slow MAS with strong 19F pulses. Fast MAS considerably reduces relaxation losses during the RFDR π-pulse train, making finite-pulse RFDR under fast-MAS the method of choice. Under intermediate MAS frequencies (25-40 kHz) and intermediate pulse duty cycles (15-30%), the 19F CSA tensor orientation has a quantifiable effect on the polarization transfer rate; thus, the RFDR buildup curves encode both distance and orientation information. At fast MAS, the impact of CSA orientation is minimized, allowing pure distance restraints to be extracted. We further investigate how relayed transfer and dipolar truncation in multifluorine environments affect polarization transfer. This fast-MAS 19F RFDR approach is complementary to 19F spin diffusion for distance measurements and will be the method of choice under high-field fast-MAS conditions that are increasingly important for protein structure determination by solid-state NMR.
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Affiliation(s)
- Matthias Roos
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
| | - Venkata S Mandala
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
| | - Mei Hong
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
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18
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Roos M, Wang T, Shcherbakov AA, Hong M. Fast Magic-Angle-Spinning 19F Spin Exchange NMR for Determining Nanometer 19F- 19F Distances in Proteins and Pharmaceutical Compounds. J Phys Chem B 2018; 122:2900-2911. [PMID: 29486126 PMCID: PMC6312665 DOI: 10.1021/acs.jpcb.8b00310] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Internuclear distances measured using NMR provide crucial constraints of three-dimensional structures but are often restricted to about 5 Å due to the weakness of nuclear-spin dipolar couplings. For studying macromolecular assemblies in biology and materials science, distance constraints beyond 1 nm will be extremely valuable. Here we present an extensive and quantitative analysis of the feasibility of 19F spin exchange NMR for precise and robust measurements of interatomic distances up to 1.6 nm at a magnetic field of 14.1 T, under 20-40 kHz magic-angle spinning (MAS). The measured distances are comparable to those achievable from paramagnetic relaxation enhancement but have higher precision, which is better than ±1 Å for short distances and ±2 Å for long distances. For 19F spins with the same isotropic chemical shift but different anisotropic chemical shifts, intermediate MAS frequencies of 15-25 kHz without 1H irradiation accelerate spin exchange. For spectrally resolved 19F-19F spin exchange, 1H-19F dipolar recoupling significantly speeds up 19F-19F spin exchange. On the basis of data from five fluorinated synthetic, pharmaceutical, and biological compounds, we obtained two general curves for spin exchange between CF groups and between CF3 and CF groups. These curves allow 19F-19F distances to be extracted from the measured spin exchange rates after taking into account 19F chemical shifts. These results demonstrate the robustness of 19F spin exchange NMR for distance measurements in a wide range of biological and chemical systems.
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Affiliation(s)
- Matthias Roos
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
| | - Tuo Wang
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
| | - Alexander A Shcherbakov
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
| | - Mei Hong
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
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19
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Salnikov ES, Raya J, De Zotti M, Zaitseva E, Peggion C, Ballano G, Toniolo C, Raap J, Bechinger B. Alamethicin Supramolecular Organization in Lipid Membranes from 19F Solid-State NMR. Biophys J 2017; 111:2450-2459. [PMID: 27926846 DOI: 10.1016/j.bpj.2016.09.048] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 09/10/2016] [Accepted: 09/29/2016] [Indexed: 11/24/2022] Open
Abstract
Alamethicins (ALMs) are antimicrobial peptides of fungal origin. Their sequences are rich in hydrophobic amino acids and strongly interact with lipid membranes, where they cause a well-defined increase in conductivity. Therefore, the peptides are thought to form transmembrane helical bundles in which the more hydrophilic residues line a water-filled pore. Whereas the peptide has been well characterized in terms of secondary structure, membrane topology, and interactions, much fewer data are available regarding the quaternary arrangement of the helices within lipid bilayers. A new, to our knowledge, fluorine-labeled ALM derivative was prepared and characterized when reconstituted into phospholipid bilayers. As a part of these studies, C19F3-labeled compounds were characterized and calibrated for the first time, to our knowledge, for 19F solid-state NMR distance and oligomerization measurements by centerband-only detection of exchange (CODEX) experiments, which opens up a large range of potential labeling schemes. The 19F-19F CODEX solid-state NMR experiments performed with ALM in POPC lipid bilayers and at peptide/lipid ratios of 1:13 are in excellent agreement with molecular-dynamics calculations of dynamic pentameric assemblies. When the peptide/lipid ratio was lowered to 1:30, ALM was found in the dimeric form, indicating that the supramolecular organization is tuned by equilibria that can be shifted by changes in environmental conditions.
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Affiliation(s)
- Evgeniy S Salnikov
- Institute of Chemistry, University of Strasbourg/CNRS, UMR7177, Strasbourg, France
| | - Jesus Raya
- Institute of Chemistry, University of Strasbourg/CNRS, UMR7177, Strasbourg, France
| | - Marta De Zotti
- ICB, Padova Unit, CNR, Department of Chemistry, University of Padova, Padova, Italy
| | - Ekaterina Zaitseva
- Department of Membrane Physiology and Technology, Institute of Physiology, University of Freiburg, Freiburg, Germany
| | - Cristina Peggion
- ICB, Padova Unit, CNR, Department of Chemistry, University of Padova, Padova, Italy
| | - Gema Ballano
- ICB, Padova Unit, CNR, Department of Chemistry, University of Padova, Padova, Italy
| | - Claudio Toniolo
- ICB, Padova Unit, CNR, Department of Chemistry, University of Padova, Padova, Italy
| | - Jan Raap
- Leiden Institute of Chemistry, Gorlaeus Laboratories, University of Leiden, Leiden, the Netherlands
| | - Burkhard Bechinger
- Institute of Chemistry, University of Strasbourg/CNRS, UMR7177, Strasbourg, France.
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20
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Ren J, Eckert H. Measurement of homonuclear magnetic dipole-dipole interactions in multiple 1/2-spin systems using constant-time DQ-DRENAR NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 260:46-53. [PMID: 26397219 DOI: 10.1016/j.jmr.2015.08.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 08/22/2015] [Accepted: 08/28/2015] [Indexed: 06/05/2023]
Abstract
A new pulse sequence entitled DQ-DRENAR (Double-Quantum based Dipolar Recoupling Effects Nuclear Alignment Reduction) was recently described for the quantitative measurement of magnetic dipole-dipole interactions in homonuclear spin-1/2 systems involving multiple nuclei. As described in the present manuscript, the efficiency and performance of this sequence can be significantly improved, if the measurement is done in the constant-time mode. We describe both the theoretical analysis of this method and its experimental validation of a number of crystalline model compounds, considering both symmetry-based and back-to-back (BABA) DQ-coherence excitation schemes. Based on the combination of theoretical analysis and experimental results we discuss the effect of experimental parameters such as the chemical shift anisotropy (CSA), the spinning rate, and the radio frequency field inhomogeneity upon its performance. Our results indicate that constant-time (CT-) DRENAR is a method of high efficiency and accuracy for compounds with multiple homonuclear spin systems with particular promise for the analysis of stronger-coupled and short T2 spin systems.
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Affiliation(s)
- Jinjun Ren
- Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.
| | - Hellmut Eckert
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstr. 30, D-48149 Münster, Germany; Instituto de Física de São Carlos, Universidade de São Paulo (USP), C.P. 369, CEP 13560-970, São Carlos, SP, Brazil.
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21
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Ren J, Eckert H. DQ-DRENAR with back-to-back (BABA) excitation: Measuring homonuclear dipole-dipole interactions in multiple spin-1/2 systems. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2015; 71:11-18. [PMID: 26483328 DOI: 10.1016/j.ssnmr.2015.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A new pulse sequence entitled DQ-DRENAR, (Double-Quantum based Dipolar Recoupling Effects Nuclear Alignment Reduction) was recently described for the quantitative measurement of magnetic dipole-dipole interactions in homonuclear spin-1/2 systems involving multiple nuclei. The double quantum coherences were created via a windowless symmetry-based pulse sequence (POST-C7). The present contribution evaluates the performance of the "Back-to-Back" excitation pulse scheme BABA-xy16 in such DRENAR experiments. Using SIMPSON simulations, special attention is given to finite pulse length effects, dipolar truncation, and chemical shift anisotropy interference. Experimental results on model compounds demonstrate good stability up to long mixing times (>10 ms) as well as high accuracy. As its dipolar coupling efficiency is relatively high (the dipolar coupling scaling factor is 4.24 times as high as that of POST-C7), DQ-DRENAR-BABA-xy16 is most appropriate for the measurement of relatively weak dipolar coupling strengths (<400 Hz). Different from POST-C7, for which the spinning rate is limited to 1/7 of the nutation frequency, DQ-DRENAR-BABA-xy16 experiments can take full advantage of ultrafast MAS experiments.
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Affiliation(s)
- Jinjun Ren
- Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.
| | - Hellmut Eckert
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstr. 30, D-48149 Münster, Germany; Instituto de Física de São Carlos, Universidade de São Paulo (USP), C.P. 369, CEP 13560-970, São Carlos, SP, Brazil.
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22
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Tkachenko AN, Mykhailiuk PK, Radchenko DS, Babii O, Afonin S, Ulrich AS, Komarov IV. Design and Synthesis of a Monofluoro-Substituted Aromatic Amino Acid as a Conformationally Restricted19F NMR Label for Membrane-Bound Peptides. European J Org Chem 2014. [DOI: 10.1002/ejoc.201301737] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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23
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Ren J, Eckert H. DQ-DRENAR: A new NMR technique to measure site-resolved magnetic dipole-dipole interactions in multispin-1/2 systems: Theory and validation on crystalline phosphates. J Chem Phys 2013; 138:164201. [DOI: 10.1063/1.4801634] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Shen M, Hu B, Lafon O, Trébosc J, Chen Q, Amoureux JP. Broadband finite-pulse radio-frequency-driven recoupling (fp-RFDR) with (XY8)4(1) super-cycling for homo-nuclear correlations in very high magnetic fields at fast and ultra-fast MAS frequencies. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 223:107-119. [PMID: 22985981 DOI: 10.1016/j.jmr.2012.07.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 07/10/2012] [Accepted: 07/16/2012] [Indexed: 06/01/2023]
Abstract
We demonstrate that inter-residue (13)C-(13)C proximities (of about 380 pm) in uniformly (13)C-labeled proteins can be probed by applying robust first-order recoupling during several milliseconds in single-quantum single-quantum dipolar homo-nuclear correlation (SQ-SQ D-HOMCOR) 2D experiments. We show that the intensity of medium-range homo-nuclear correlations in these experiments is enhanced using broadband first-order finite-pulse radio-frequency-driven recoupling (fp-RFDR) NMR sequence with a nested (XY8)4(1) super-cycling. The robustness and the efficiency of the fp-RFDR-(XY8)4(1) method is demonstrated at high magnetic field (21.1T) and high Magic-Angle Spinning (MAS) speeds (up to 60 kHz). The introduced super-cycling, formed by combining phase inversion and a global four-quantum phase cycle, improves the robustness of fp-RFDR to (i) chemical shift anisotropy (CSA), (ii) spread in isotropic chemical shifts, (iii) rf-inhomogeneity and (iv) hetero-nuclear dipolar couplings for long recoupling times. We show that fp-RFDR-(XY8)4(1) is efficient sans (1)H decoupling, which is beneficial for temperature-sensitive biomolecules. The efficiency and the robustness of fp-RFDR-(XY8)4(1) is investigated by spin dynamics numerical simulations as well as solid-state NMR experiments on [U-(13)C]-L-histidine·HCl, a tetra-peptide (Fmoc-[U-(13)C,(15)N]-Val-[U-(13)C,(15)N]-Ala-[U-(13)C,(15)N]-Phe-Gly-t-Boc) and Al(PO(3))(3).
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Affiliation(s)
- Ming Shen
- Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China
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25
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Dürr UHN, Afonin S, Hoff B, de Luca G, Emsley JW, Ulrich AS. Alignment of Druglike Compounds in Lipid Bilayers Analyzed by Solid-State 19F-NMR and Molecular Dynamics, Based on Dipolar Couplings of Adjacent CF3 Groups. J Phys Chem B 2012; 116:4769-82. [DOI: 10.1021/jp212339k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ulrich H. N. Dürr
- Institute
of Organic Chemistry
and CFN, Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg
6, 76131 Karlsruhe, Germany
| | - Sergii Afonin
- Institute
of Organic Chemistry
and CFN, Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg
6, 76131 Karlsruhe, Germany
| | - Barbara Hoff
- Bioprocess Engineering, IMVM, Fritz-Haber-Weg
2, 76131 Karlsruhe, Germany
| | - Giuseppina de Luca
- Dipartimento di Chimica, University of Calabria, Campus di Arcavacata, Via Pietro
Bucci Cubo 12C, I-87036 Rende (Cosenza), Italy
| | - James W. Emsley
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, U.K
| | - Anne S. Ulrich
- Institute
of Organic Chemistry
and CFN, Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg
6, 76131 Karlsruhe, Germany
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Wang Q, Hu B, Fayon F, Trébosc J, Legein C, Lafon O, Deng F, Amoureux JP. Double-quantum 19F–19F dipolar recoupling at ultra-fast magic angle spinning NMR: application to the assignment of 19F NMR spectra of inorganic fluorides. Phys Chem Chem Phys 2009; 11:10391-5. [DOI: 10.1039/b914468d] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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27
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Dürr UHN, Grage SL, Witter R, Ulrich AS. Solid state 19F NMR parameters of fluorine-labeled amino acids. Part I: aromatic substituents. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 191:7-15. [PMID: 18155936 DOI: 10.1016/j.jmr.2007.11.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 10/30/2007] [Accepted: 11/21/2007] [Indexed: 05/25/2023]
Abstract
Structural parameters of peptides and proteins in biomembranes can be directly measured by solid state NMR of selectively labeled amino acids. The 19F nucleus is a promising label to overcome the low sensitivity of 2H, 13C or 15N, and to serve as a background-free reporter group in biological compounds. To make the advantages of solid state 19F NMR fully available for structural studies of polypeptides, we have systematically measured the chemical shift anisotropies and relaxation properties of the most relevant aromatic and aliphatic 19F-labeled amino acids. In this first part of two consecutive contributions, six different 19F-substituents on representative aromatic side chains were characterized as polycrystalline powders by static and MAS experiments. The data are also compared with results on the same amino acids incorporated in synthetic peptides. The spectra show a wide variety of lineshapes, from which the principal values of the CSA tensors were extracted. In addition, temperature-dependent T(1) and T(2) relaxation times were determined by 19F NMR in the solid state, and isotropic chemical shifts and scalar couplings were obtained in solution.
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Affiliation(s)
- Ulrich H N Dürr
- Max-Planck-Institute for Biophysical Chemistry, Department of NMR-Based Structural Biology, Am Fassberg 11, 37077 Göttingen, Germany
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28
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Grage SL, Suleymanova AV, Afonin S, Wadhwani P, Ulrich AS. Solid state NMR analysis of the dipolar couplings within and between distant CF3-groups in a membrane-bound peptide. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 183:77-86. [PMID: 16919983 DOI: 10.1016/j.jmr.2006.07.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 07/11/2006] [Accepted: 07/14/2006] [Indexed: 05/11/2023]
Abstract
Dipolar couplings contain information on internuclear distances as well as orientational constraints. To characterize the structure of the antimicrobial peptide gramicidin S when bound to model membranes, two rigid 4-CF3-phenylglycine labels were attached to the cyclic backbone such that they reflect the behavior of the entire peptide. By solid state 19F NMR we measured the homonuclear dipolar couplings of the two trifluoromethyl-groups in oriented membrane samples. Using the CPMG experiment, both the strong couplings within each CF3-group as well as the weak coupling between the two CF3-groups could be detected. An intra-CF3-group dipolar coupling of 86 Hz and a weak inter-group coupling of 20 Hz were obtained by lineshape simulation of the complex dipolar spectrum. It is thus possible to explore the large distance range provided by 19F-labels and to resolve weak dipolar couplings even in the presence of strong intra-CF3 couplings. We applied this approach to distinguish and assign two epimers of the labeled gramicidin S peptide on the basis of their distinct 19F dipolar coupling patterns.
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Affiliation(s)
- Stephan L Grage
- Institute of Biological Interfaces, Forschungszentrum Karlsruhe, P.O. Box 3640, 76021 Karlsruhe, Germany
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29
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Louie EA, Chirakul P, Raghunathan V, Sigurdsson ST, Drobny GP. Using solid-state 31P{19F} REDOR NMR to measure distances between a trifluoromethyl group and a phosphodiester in nucleic acids. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 178:11-24. [PMID: 16213170 DOI: 10.1016/j.jmr.2005.06.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2005] [Revised: 06/25/2005] [Accepted: 06/29/2005] [Indexed: 05/04/2023]
Abstract
REDOR is a solid-state NMR technique frequently applied to biological structure problems. Through incorporation of phosphorothioate groups in the nucleic acid backbone and mono-fluorinated nucleotides, 31P{19F} REDOR has been used to study the binding of DNA to drugs and RNA to proteins through the detection of internuclear distances as large as 13-14 A. In this work, 31P{19F} REDOR is further refined for use in nucleic acids by the combined use of selective placement of phosphorothioate groups and the introduction of nucleotides containing trifluoromethyl (-CF3) groups. To ascertain the REDOR-detectable distance limit between an unique phosphorous spin and a trifluoromethyl group and to assess interference from intermolecular couplings, a series of model compounds and DNA dodecamers were synthesized each containing a unique phosphorous label and trifluoromethyl group or a single 19F nucleus. The dipolar coupling constants of the various 31P and 19F or -CF3 containing compounds were compared using experimental and theoretical dephasing curves involving several models for intermolecular interactions.
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Affiliation(s)
- Elizabeth A Louie
- University of Washington, Chemistry Department, Campus Box 351700, Seattle, WA 98195-1700, USA
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30
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Afonin S, Glaser RW, Berditchevskaia M, Wadhwani P, Gührs KH, Möllmann U, Perner A, Ulrich AS. 4-fluorophenylglycine as a label for 19F NMR structure analysis of membrane-associated peptides. Chembiochem 2004; 4:1151-63. [PMID: 14613106 DOI: 10.1002/cbic.200300568] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The non-natural amino acid 4-fluorophenylglycine (4F-Phg) was incorporated into several representative membrane-associated peptides for dual purpose. The (19)F-substituted ring is directly attached to the peptide backbone, so it not only provides a well-defined label for highly sensitive (19)F NMR studies but, in addition, the D and L enantiomers of the stiff side chain may serve as reporter groups on the transient peptide conformation during the biological function. Besides peptide synthesis, which is accompanied by racemisation of 4F-Phg, we also describe separation of the epimers by HPLC and removal of trifluoroacetic acid. As a first example, 18 different analogues of the fusogenic peptide "B18" were prepared and tested for induction of vesicle fusion; the results confirmed that hydrophobic sites tolerated 4F-Phg labelling. Similar fusion activities within each pair of epimers suggest that the peptide is less structured in the fusogenic transition state than in the helical ground state. In a second example, five doubly labelled analogues of the antimicrobial peptide gramicidin S were compared by using bacterial growth inhibition assays. This cyclic beta-sheet peptide could accommodate both L and D substituents on its hydrophobic face. As a third example, we tested six analogues of the antimicrobial peptide PGLa. The presence of d-4F-Phg reduced the biological activity of the peptide by interfering with its amphiphilic alpha-helical fold. Finally, to illustrate the numerous uses of l-4F-Phg in (19)F NMR spectroscopy, we characterised the interaction of labelled PGLa with uncharged and negatively charged membranes. Observing the signal of the free peptide in an aqueous suspension of unilamellar vesicles, we found a linear saturation behaviour that was dominated by electrostatic attraction of the cationic PGLa. Once the peptide is bound to the membrane, however, solid-state (19)F NMR spectroscopy of macroscopically oriented samples revealed that the charge density has virtually no further influence on the structure, alignment or mobility of the peptide.
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Affiliation(s)
- Sergii Afonin
- Forschungszentrum Karlsruhe, IFIA, P.O.B. 3640, 76021 Karlsruhe, Germany
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31
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Brinkmann A, Schmedt auf der Günne J, Levitt MH. Homonuclear zero-quantum recoupling in fast magic-angle spinning nuclear magnetic resonance. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2002; 156:79-96. [PMID: 12081445 DOI: 10.1006/jmre.2002.2525] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Solid-state magic-angle-spinning NMR pulse sequences which implement zero-quantum homonuclear dipolar recoupling are designed with the assistance of symmetry theory. The pulse sequences are compensated on a short time scale by the use of composite pulses and on a longer time scale by the use of supercycles. (13)C dipolar recoupling is demonstrated in powdered organic solids at high spinning frequencies. The new sequences are compared to existing pulse sequences by means of numerical simulations. Experimental two-dimensional magnetization exchange spectra are shown for [U-(13)C]-L-tyrosine.
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Affiliation(s)
- Andreas Brinkmann
- Division of Physical Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, 10691, Sweden
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