Topic
Multidimensional NMR Techniques
About: Multidimensional NMR Techniques is a research topic. Over the lifetime, 32 publications have been published within this topic receiving 1398 citations.
Papers
Book•
25 Jun 1998
TL;DR: In this paper, the authors discuss the use of NMR data for structural analysis of nuclei and discuss some of the most common NMR techniques in the literature, as well as their application in the field of molecular structural analysis.
Abstract: CHAPTER 1.USING SPECTROSCOPIC DATA IN ORGANIC STRUCTURE ANALYSIS 1.1 A Glimpse of the Methods in Common Use 1.2 Characteristics of the Methods in Common Use 1.3 Steps in Establishing a Molecular Structure 1.4 Molecular Formula (MF) and Unsaturation Number (UN) 1.5 Substructures, Working Structures, and Final Structures 1.6 Limitations of Spectroscopic Data in Structure Analysis CHAPTER 2. INTRODUCTION TO NUCLEAR MAGNETIC RESONANCE 2.1 A Glimpse of the NMR Phenomenon 2.2 Commonly Studied Nuclei 2.3 Obtaining an NMR Spectrum 2.4 Magnetic Shielding 2.5 Relaxation Effects 2.6 Effect of Relaxation and NOE on Peak Intensities 2.7 Electric Quadrupole Effects 2.8 Measurement and Presentation of Data 2.9 Sample Preparation and Sample Size 2.10 Common Impurities in NMR Spectra 2.11 Other Useful Nuclei CHAPTER 3. INTERPRETATION AND USE OF PROTON AND CARBON CHEMICAL SHIFTS 3.1 A Glimpse of Chemical Shifts and Peak Areas 3.2 Terms and Conventions 3.3 Factors That Determine Chemical Shifts 3.4 Chemical Shift Positions of 'H/'3C Attached to Common Functional Groups 3.5 Chemical Shift Equivalence 3.6 Characteristic Chemical Shifts for Different Protons and Carbons 3.7 Using Databases to Estimate '3C NMR Chemical Shifts 3.8 Making Configurational Assignments Based on Chemical Shifts: Case Examples CHAPTER 4. INTERPRETATION AND USE OF PROTON AND CARBON COUPLING CONSTANTS 4.1 A Glimpse of Coupling Constants 4.2 First-Order Spectra and the n + 1 Rule 4.3 Terms and Conventions 4.4 Common Coupled Spin Systems 4.5 Magnetic Nonequivalence 4.6 Using Coupling Constants to Understand the Appearance of Spectra and Make Assignments 4.7 Coupling Constant Values for Different Carbon and Proton Types 4.8 Using Coupling Constants to Make Configurational Assignments 4.9 Ways to Simplify or Eliminate Coupling Effects 4.10 The Nuclear Overhauser effect 4.11 Additional Ways to Obtain J Values CHAPTER 5. MULTIPLE-PULSE AND MULTIDIMENSIONAL NMR TECHNIQUES 5.1 A Glimpse of Multiple-Pulse NMR Methods 5.2 Elements of Multiple-Pulse NMR 5.3 One-Dimensional NMR Techniques 5.4 Two-Dimensional NMR Techniques 5.5 Using Two-Dimensional NMR in Assigning Spectra 5.6 Using Two-Dimensional NMR Data to Determine an Unknown Structure 5.7 Strategies for Using 2D NMR in Structure Determination 5.8 Use of NOESY and ROESY to Determine Relative Stereochemistry and Conformations 5.9 Specialized Pulse Sequences 5.10 Configurational Analysis Based on Coupling Constants: Experimental Measurement of .3 J[CH 5.11 Computer-Assisted Structure Elucidation 5.12 Future Prospects in Multidimensional NMR CHAPTER 6. MASS SPECTROMETRY: CORE TECHNIQUES AND IONIZATION PROCESSES 6.1 A Glimpse of Mass Spectrometry 6.2 Measurement, Presentation of Data, and Nomenclature 6.3 Isotopes, Atomic Composition, Molecular Formulas, and Ionic Mass: Low and High Resolution and Measurements 6.4 Different Ionization Techniques in Mass Spectrometry 6.5 Different Techniques for Analyzing Ions in Mass Spectrometry 6.6 Detectors in Mass Spectrometry 6.7 Hyphenated Mass Spectrometry 6.8 Tandem Mass Spectrometry 6.9 Future Prospects CHAPTER 7. MASS SPECTROMETRY ANALYSIS OF SMALL AND LARGE MOLECULES 7.1 A Glimpse of Molecular Ions Revisited 7.2 Small-Molecule Mass Spectral Analysis 7.3 Large-Molecule Mass Spectrometry 7.4 Future Prospects CHAPTER 8. FRAGMENTATION PROCESSES IN ELECTRON IONIZATION MASS SPECTROMETRY 8.1 A Glimpse of Fragmentation in Mass Spectrometry 8.2 Interpreting a Low Resolution Electron Ionization Mass Spectrum 8.3 Fragmentation Processes 8.4 Identification of Functionality from Fragmentation Processes 8.5 Schematic Approach for the Interpretation of an EIMS CHAPTER 9. INFRARED SPECTROSCOPY 9.1 A Glimpse of Infrared Spectroscopy 9.2 Measurement and Presentation of Data 9.3 The Fundamentals 9.4 Identifying Functional Groups 9.5 Interpreted Infrared Spectra 9.6 Use of Infrared Databases CHAPTER 10. OPTICAL AND CHIROPTICAL TECHNIQUES: ULTRAVIOLET SPECTROSCOPY 10.1 A Glimpse of Ultraviolet Spectroscopy 10.2 Measurement and Presentation of Data 10.3 The Fundamentals for Interpreting Spectra 10.4 Identifying Functional Groups 10.5 Theoretical Simulations of UV Spectra 10.6 The Behavior of Chiral Chromophores ORD/CD 10.7 The Exciton Chirality Method 10.8 Other Ways to Examine Chiral Chromophores CHAPTER 11. STRATEGIES OF DETERMINING STRUCTURE AND STEREOCHEMISTRY: SPECTROSCOPIC DATA TRANSLATED INTO STRUCTURES 11.1 A Glimpse of the Combined Use of Spectroscopic Data 11.2 The Strategies of Determining Structure and Stereochemistry 11.3 Dereplication Strategies 11.4 Worked Examples of Deriving Structures from Spectroscopic Data CHAPTER 12. PROBLEMS IN ORGANIC STRUCTURE ANALYSIS 12.1 A Glimpse of the Scope of the 51 Unknowns 12.2 Using the Spectra, Accompanying Information, and Other Resources APPENDICES A. COLLECTIONS OF SPECTRA OR DATA TABLES B. SHAPE OF MS CLUSTERS C. CAS REGISTRY NUMBERS FOR UNKNOWNS D. GLOSSARY AND ABBREVIATIONS
369 citations
TL;DR: Multidimensional NMR techniques are providing new information on the structure and dynamics of protein folding intermediates and both partly folded and unfolded states.
Abstract: NMR has emerged as an important tool for studies of protein folding because of the unique structural insights it can provide into many aspects of the folding process. Applications include measurements of kinetic folding events and structural characterization of folding intermediates, partly folded states, and unfolded states. Kinetic information on a time scale of milliseconds or longer can be obtained by real-time NMR experiments and by quench-flow hydrogen-exchange pulse labeling. Although NMR cannot provide direct information on the very rapid processes occurring during the earliest stages of protein folding, studies of isolated peptide fragments provide insights into likely protein folding initiation events. Multidimensional NMR techniques are providing new information on the structure and dynamics of protein folding intermediates and both partly folded and unfolded states.
136 citations
TL;DR: Ultrafast multidimensional NMR techniques are used to monitor the adenine-induced folding of an adenin-sensing riboswitch in real time, with nucleotide-resolved resolution, to determine the structure of RNA folding intermediates and conformational trajectories.
Abstract: Conformational transitions and structural rearrangements are central to the function of many RNAs yet remain poorly understood. We have used ultrafast multidimensional NMR techniques to monitor the adenine-induced folding of an adenine-sensing riboswitch in real time, with nucleotide-resolved resolution. By following changes in 2D spectra at rates of approximately 0.5 Hz, we identify distinct steps associated with the ligand-induced folding of the riboswitch. Following recognition of the ligand, long range loop-loop interactions form and are then progressively stabilized before the formation of a fully stable complex over approximately 2–3 minutes. The application of these ultrafast multidimensional NMR methods provides the opportunity to determine the structure of RNA folding intermediates and conformational trajectories.
113 citations
TL;DR: The carotenoid profile of typical tomato juice was successfully determined with minimal purification procedures and the use of one-dimensional NMR enabled the rapid identification of lycopene isomers, thereby minimizing further isomerization of (all-E)-lycopene as compared to HPLC data.
Abstract: Epidemiological data have shown a link between dietary intake of tomatoes and tomato products (rich in carotenoids) and a decreased risk of chronic diseases. The carotenoid profile in tomato products depends on tomato variety as well as the thermal conditions used in processing. The final carotenoid profile may affect the bioaccessibility and bioavailability of these biomolecules. Therefore, nondestructive, reliable methods are needed to characterize the structural and stereochemical variation of carotenoids. CDCl(3) rapid extraction was used to extract carotenoids from tomato juice as an alternative rapid procedure that minimizes solvents and time consumption prior to NMR analysis. The profile of these biomolecules was characterized by application of high-resolution multidimensional NMR techniques using a cryogenic probe. The combination of homonuclear and heteronuclear two-dimensional NMR techniques served to identify (all-E)-, (5Z)-, (9Z)-, and (13Z)-lycopene isomers and other carotenoids such as (all-E)-beta-carotene and (15Z)-phytoene dissolved in the extracted lipid mixture. The use of one-dimensional NMR enabled the rapid identification of lycopene isomers, thereby minimizing further isomerization of (all-E)-lycopene as compared to HPLC data. On the basis of the assignments accomplished, the carotenoid profile of typical tomato juice was successfully determined with minimal purification procedures.
91 citations
TL;DR: This paper evaluated a series of NMR solvents for easy and versatile single-step extraction using the (13)C-labeled photosynthetic bacterium Rhodobacter sphaeroides, and chose methanol-d(4) (MeOD) as a semipolar extraction solvent that can sufficiently sharpen the line width and affords better-quality NMR spectra.
Abstract: Nuclear magnetic resonance (NMR) has become a key technology in metabolomics, with the use of stable isotope labeling and advanced heteronuclear multidimensional NMR techniques. In this paper, we focus on the evaluation of extraction solvents to improve NMR-based methodologies for metabolomics. Line broadening is a serious barrier to detecting signals and the annotation of metabolites using multidimensional NMR. We evaluated a series of NMR solvents for easy and versatile single-step extraction using the (13)C-labeled photosynthetic bacterium Rhodobacter sphaeroides, which shows pronounced broadening of NMR signals. The performance of each extraction solvent was judged using 2D (1)H-(13)C heteronuclear single quantum coherence (HSQC) spectra, considering three metrics: (1) distribution of the line width at half height, (2) number of observed signals, and (3) the total observed signal intensity. Considering the total rank values for the three metrics, we chose methanol-d(4) (MeOD) as a semipolar extraction solvent that can sufficiently sharpen the line width and affords better-quality NMR spectra. We also evaluated the series of extraction solvents by means of inductively coupled plasma optical emission spectroscopy (ICP-OES) based ionomics approach. It was also indicated that MeOD is useful for excluding paramagnetic ions as well as macromolecules in an easy single-step extraction. MeOD extraction also appeared to be effective for other bacterial and animal samples. An additional advantage of this semipolar solvent is that it supplements the aqueous (polar) buffer system reported by many groups. The flexible, appropriate application of polar and semipolar extraction should contribute to the large-scale analysis of metabolites.
72 citations
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