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Mishra SK, Suryaprakash N. Pure shift edited NMR methodologies for the extraction of Homo- and heteronuclear couplings with ultra-high resolution. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2023; 136-137:1-60. [PMID: 37716754 DOI: 10.1016/j.pnmrs.2023.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 01/20/2023] [Accepted: 02/01/2023] [Indexed: 09/18/2023]
Abstract
The scalar couplings that result in the splitting of the signals in the NMR spectrum arise due to the interaction of the nuclear spins, whereby the spin polarization is transmitted through chemical bonds. The interaction strengths depend inter alia on the number of consecutive chemical bonds intervening between the two interacting spins and on the molecular conformation. The pairwise interaction of many spins in a molecule resulting in a complex spectrum poses a severe challenge to analyse the spectrum and hence the determination of magnitudes and signs of homo- and heteronuclear couplings. The problem is more severe in the analysis of 1H spectra than the spectra of most of the other nuclei due to the often very small chemical shift dispersion. As a consequence, the straightforward analysis and the accurate extraction of the coupling constants from the 1H spectrum of a complex spin system continues to remain a challenge, and often may be a formidable task. Over the years, the several pure shift-based one-dimensional and two-dimensional methodologies have been developed by workers in the field, which provide broadband homonuclear decoupling of proton spectra, removing the complexity but at the cost of the very informative scalar couplings. To circumvent this problem, several one-dimensional and two-dimensional NMR experiments have been developed for the determination of homonuclear and heteronuclear couplings (nJHX, where n = 1,2,3) while retaining the high resolution obtained by implementing pure shift strategies. This review attempts to summarize the extensive work reported by a large number of researchers over the years for the accurate determination of homo- and heteronuclear scalar couplings.
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Affiliation(s)
- Sandeep Kumar Mishra
- Department of Physics and NMR Research Centre, Indian Institute of Science Education and Research, Pune 411008, India.
| | - N Suryaprakash
- NMR Research Centre and Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India.
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2
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Raics M, Timári I, Szilágyi L, Gabius HJ, Kövér KE. Introducing 77Se NMR Spectroscopy to Analyzing Galectin -Ligand Interaction. Methods Mol Biol 2022; 2442:105-123. [PMID: 35320522 DOI: 10.1007/978-1-0716-2055-7_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Their emerging nature as multifunctional effectors explains the large interest to monitor glycan binding to galectins and to define bound-state conformer(s) of their ligands in solution. Basically, NMR spectroscopy facilitates respective experiments. Towards developing new and even better approaches for these purposes, extending the range of exploitable isotopes beyond 1H, 13C, and 15N offers promising perspectives. Having therefore prepared selenodigalactoside and revealed its bioactivity as galectin ligand, monitoring of its binding by 77Se NMR spectroscopy at a practical level becomes possible by setting up a 2D 1H, 77Se CPMG-HSQBMC experiment including CPMG-INEPT long-range transfer. This first step into applying 77Se as sensor for galectin binding substantiates its potential for screening relative to inhibitory potencies in compound mixtures and for achieving sophisticated epitope mapping. The documented strategic combination of synthetic carbohydrate chemistry and NMR spectroscopy prompts to envision to work with isotopically pure 77Se-containing β-galactosides and to build on the gained experience with 77Se by adding 19F as second sensor in doubly labeled glycosides.
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Affiliation(s)
- Mária Raics
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Debrecen, Hungary
| | - István Timári
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Debrecen, Hungary
| | - László Szilágyi
- Department of Organic Chemistry, University of Debrecen, Debrecen, Hungary
| | - Hans-Joachim Gabius
- Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Munich, Germany.
| | - Katalin E Kövér
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Debrecen, Hungary.
- MTA-DE Molecular Recognition and Interaction Research Group, University of Debrecen, Debrecen, Hungary.
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3
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Raics M, Timári I, Diercks T, Szilágyi L, Gabius H, Kövér KE. Selenoglycosides as Lectin Ligands: 77 Se-Edited CPMG-HSQMBC NMR Spectroscopy To Monitor Biomedically Relevant Interactions. Chembiochem 2019; 20:1688-1692. [PMID: 30828921 PMCID: PMC6618100 DOI: 10.1002/cbic.201900088] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Indexed: 12/25/2022]
Abstract
The fundamental importance of protein-glycan recognition calls for specific and sensitive high-resolution techniques for their detailed analysis. After the introduction of 19 F NMR spectroscopy to study the recognition of fluorinated glycans, a new 77 Se NMR spectroscopy method is presented for complementary studies of selenoglycans with optimised resolution and sensitivity, in which direct NMR spectroscopy detection on 77 Se is replaced by its indirect observation in a 2D 1 H,77 Se HSQMBC spectrum. In contrast to OH/F substitution, O/Se exchange allows the glycosidic bond to be targeted. As an example, selenodigalactoside recognition by three human galectins and a plant toxin is readily indicated by signal attenuation and line broadening in the 2D 1 H,77 Se HSQMBC spectrum, in which CPMG-INEPT long-range transfer ensures maximal detection sensitivity, clean signal phases, and reliable ligand ranking. By monitoring competitive displacement of a selenated spy ligand, the selective 77 Se NMR spectroscopy approach may also be used to screen non-selenated compounds. Finally, 1 H,77 Se CPMG-INEPT transfer allows further NMR sensors of molecular interaction to be combined with the specificity and resolution of 77 Se NMR spectroscopy.
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Affiliation(s)
- Mária Raics
- Department of Inorganic and Analytical ChemistryUniversity of DebrecenEgyetem tér 14032DebrecenHungary
| | - István Timári
- Department of Inorganic and Analytical ChemistryUniversity of DebrecenEgyetem tér 14032DebrecenHungary
| | - Tammo Diercks
- NMR FacilityCIC bioGUNEBizkaia Technology Park, Bld 80048170DerioSpain
| | - László Szilágyi
- Department of Organic ChemistryUniversity of DebrecenEgyetem tér 14032DebrecenHungary
| | - Hans‐Joachim Gabius
- Tierärztliche Fakultät, Institut für Physiologische ChemieLudwig-Maximilians-Universität MünchenVeterinärstrasse 1380539MunichGermany
| | - Katalin E. Kövér
- Department of Inorganic and Analytical ChemistryUniversity of DebrecenEgyetem tér 14032DebrecenHungary
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4
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Lin Y, Zeng Q, Lin L, Chen Z, Barker PB. High-resolution methods for the measurement of scalar coupling constants. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:135-159. [PMID: 30527134 DOI: 10.1016/j.pnmrs.2018.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 08/14/2018] [Accepted: 08/14/2018] [Indexed: 06/09/2023]
Abstract
Scalar couplings provide important information regarding molecular structure and dynamics. The measurement of scalar coupling constants constitutes a topic of interest and significance in NMR spectroscopy. However, the measurement of J values is often not straightforward because of complex signal splitting patterns and signal overlap. Many methods have been proposed for the measurement of scalar coupling constants, both for homonuclear and heteronuclear cases. Different approaches to the measurement of scalar coupling constants are reviewed here with several applications presented. The accurate measurement of scalar coupling constants can greatly facilitate molecular structure elucidation and the study of molecule dynamics.
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Affiliation(s)
- Yanqin Lin
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China.
| | - Qing Zeng
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Liangjie Lin
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Zhong Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Peter B Barker
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; F. M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
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5
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Bigler P, Furrer J. Why is HMBC superior to LR-HSQC? Influence of homonuclear couplings J HH' on the intensity of long-range correlations. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:1101-1116. [PMID: 29907970 DOI: 10.1002/mrc.4762] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 05/16/2018] [Accepted: 06/05/2018] [Indexed: 06/08/2023]
Abstract
Long-range heteronuclear single quantum correlation (LR-HSQC) experiments may be applied as an alternative to heteronuclear multiple-bond correlation (HMBC) experiments for detecting long-range correlations but has never enjoyed popularity for that purpose. To the best of our knowledge, the exact reasons have not yet been fully established. For both experiments, it is widely accepted that the evolution of proton-proton homonuclear couplings JHH' during the polarization transfer delays Δ leads to significant losses, and that the intensity of the observable coherence is zero when JHH' matches the condition Δ = 0.5/JHH' . Here, we analyze the influence of JHH' on the intensity of long-range correlations in HMBC and LR-HSQC spectra. We show that for both experiments long-range correlations will not be canceled because of homonuclear couplings JHH' . Our theoretical and experimental results definitely establish and validate the superiority of HMBC-based experiments among the family of heteronuclear long-range correlation experiments: (a) the overall cross peak's intensity is higher, and (b) in LR-HSQC experiments, the intensity of the long-range cross peaks is additionally influenced in an unwanted way by the magnitude and number of passive homonuclear proton-proton couplings JHH' .
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Affiliation(s)
- Peter Bigler
- Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012, Bern, Switzerland
| | - Julien Furrer
- Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012, Bern, Switzerland
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6
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Timári I, Kövér KE. Broadband homonuclear decoupled HSQMBC methods. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:910-917. [PMID: 29240977 DOI: 10.1002/mrc.4700] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 12/03/2017] [Accepted: 12/05/2017] [Indexed: 06/07/2023]
Abstract
Long-range heteronuclear coupling constants convey invaluable information for stereochemical and conformational analysis of molecules from synthetic and natural origin. Here, we report a real-time Zangger-Sterk CPMG-HSQMBC method for the precise and direct measurement of multiple-bond heteronuclear couplings. It is demonstrated that the real-time acquisition strategy combined with multiple slice selective excitation can provide substantial improvement in sensitivity (or reduction of experimental time) as compared to other variants of broadband homonuclear decoupled HSQMBC methods published previously. Scope and limitations of the different strategies applied for decoupling are reviewed. Moreover, practical guidelines for the choice of the most appropriate method are also presented. Applications are given on a metal complex incorporating P-heterocycles and two diglycosyl-selenides for the extraction of n J(1 H, 31 P) and n J(1 H, 77 Se), respectively.
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Affiliation(s)
- István Timári
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H-4032, Debrecen, Hungary
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, 43210, Columbus, OH, USA
| | - Katalin E Kövér
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H-4032, Debrecen, Hungary
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7
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Koskela H, Kilpeläinen I, Heikkinen S. ME-CAGEBIRD r,X-CPMG-HSQMBC. A phase sensitive, multiplicity edited long range HSQC with absorptive line shapes. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 272:114-122. [PMID: 27689530 DOI: 10.1016/j.jmr.2016.09.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/15/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
ME-CAGEBIRDr,X-CPMG-HSMBC pulse sequence is a phase sensitive, carbon multiplicity edited 2D-experiment for detecting heteronuclear correlations originating from long-range 1H, 13C-couplings, nJCH. The presented method allows measurement of nJCH-values as well as is capable of separating different carbon types in subspectra (13C/13CH2 and 13CH/13CH3) with minimal amount of cross talk i.e. cross peaks from wrong carbon multiplicity. Pure lineshapes and clean subspectra are achieved by utilizing CPMG in polarization transfer period, CRISIS-approach in multiplicity editing period and zero-quantum filtration. The obtained spectral properties together with simple setup of the experiment make ME-CAGEBIRDr,X-CPMG-HSMBC a useful addition into synthetic organic chemistry oriented NMR-tool collection.
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Affiliation(s)
- Harri Koskela
- VERIFIN, Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland
| | - Ilkka Kilpeläinen
- Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland
| | - Sami Heikkinen
- Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland.
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8
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Glanzer S, Kunert O, Zangger K. Determination of unresolved heteronuclear scalar coupling constants by J(up)-HSQMBC. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 268:88-94. [PMID: 27183090 DOI: 10.1016/j.jmr.2016.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 02/25/2016] [Accepted: 05/05/2016] [Indexed: 06/05/2023]
Abstract
Long-range heteronuclear scalar coupling constants provide important structural information, which is necessary for obtaining stereospecific assignment or dihedral angle information. The measurement of small proton-carbon splittings is particularly difficult due to the low natural abundance of carbon-13 and the presence of homonuclear couplings of similar size. Here we present a real-time J-upscaled HSQMBC, which allows the measurement of heteronuclear coupling constants even if they are hidden in the signal linewidth of a regular spectrum.
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Affiliation(s)
- Simon Glanzer
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Austria
| | - Olaf Kunert
- Institute of Pharmaceutical Sciences/Pharmaceutical Chemistry, University of Graz, Austria
| | - Klaus Zangger
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Austria.
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9
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Saurí J, Frédérich M, Tchinda AT, Parella T, Williamson RT, Martin GE. Carbon Multiplicity Editing in Long-Range Heteronuclear Correlation NMR Experiments: A Valuable Tool for the Structure Elucidation of Natural Products. JOURNAL OF NATURAL PRODUCTS 2015; 78:2236-2241. [PMID: 26305494 DOI: 10.1021/acs.jnatprod.5b00447] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A recently developed NMR method to simultaneously obtain both long-range heteronuclear correlations and carbon multiplicity information in a single experiment, ME-selHSQMBC, is demonstrated as a potentially useful technique for chemical shift assignment and structure elucidation of natural products presenting complicated NMR spectra. Carbon multiplicities, even for C/CH2 and odd for CH/CH3 resonances, can be distinguished directly from the relative positive/negative phase of cross-peaks. In addition, connectivity networks can be further extended by incorporating a TOCSY propagation step. Staurosporine (1) and sungucine (2) are utilized as model compounds to demonstrate these techniques.
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Affiliation(s)
- Josep Saurí
- NMR Structure Elucidation, Process and Analytical Chemistry, Merck & Co. Inc. , Rahway, New Jersey 07065, United States
| | - Michel Frédérich
- Laboratory of Pharmacognosy, Department of Pharmacy, CIRM, University of Liège , B36, 4000 Liège, Belgium
| | - Alembert T Tchinda
- Center for Studies on Medicinal Plants and Traditional Medicine, Institute of Medical Research and Medicinal Plants Studies (IMPM) , P.O. Box 6163, Yaoundé, Cameroon
| | - Teodor Parella
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona , E-08193 Bellaterra, Barcelona, Spain
| | - R Thomas Williamson
- NMR Structure Elucidation, Process and Analytical Chemistry, Merck & Co. Inc. , Rahway, New Jersey 07065, United States
| | - Gary E Martin
- NMR Structure Elucidation, Process and Analytical Chemistry, Merck & Co. Inc. , Rahway, New Jersey 07065, United States
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10
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Timári I, Szilágyi L, Kövér KE. PSYCHE CPMG–HSQMBC: An NMR Spectroscopic Method for Precise and Simple Measurement of Long‐Range Heteronuclear Coupling Constants. Chemistry 2015; 21:13939-42. [DOI: 10.1002/chem.201502641] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Indexed: 11/08/2022]
Affiliation(s)
- István Timári
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H‐4032 Debrecen (Hungary)
| | - László Szilágyi
- Department of Organic Chemistry, University of Debrecen, Egyetem tér 1, H‐4032 Debrecen (Hungary)
| | - Katalin E. Kövér
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H‐4032 Debrecen (Hungary)
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11
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Saurí J, Sistaré E, Thomas Williamson R, Martin GE, Parella T. Implementing multiplicity editing in selective HSQMBC experiments. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 252:170-175. [PMID: 25702573 DOI: 10.1016/j.jmr.2015.01.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 01/07/2015] [Accepted: 01/11/2015] [Indexed: 06/04/2023]
Abstract
Even C/CH(2) and odd CH/CH(3) carbon-multiplicity information can be directly distinguished from the relative positive/negative phase of cross-peaks in a novel ME (Multiplicity-Edited)-selHSQMBC experiment. The method can be extended by a TOCSY propagation step, and it is fully compatible for the simultaneous and precise determination of long-range heteronuclear coupling constants. Broadband homonuclear decoupling techniques can also be incorporated to enhance sensitivity and signal resolution by effective collapse of J(HH) multiplets.
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Affiliation(s)
- Josep Saurí
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, Facultat de Ciències, E-08193 Bellaterra (Barcelona), Catalonia, Spain; NMR Structure Elucidation, Process and Analytical Chemistry, Merck & Co. Inc., 126 E. Lincoln Avenue, Rahway, NJ 07065, USA
| | - Eduard Sistaré
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, Facultat de Ciències, E-08193 Bellaterra (Barcelona), Catalonia, Spain
| | - R Thomas Williamson
- NMR Structure Elucidation, Process and Analytical Chemistry, Merck & Co. Inc., 126 E. Lincoln Avenue, Rahway, NJ 07065, USA
| | - Gary E Martin
- NMR Structure Elucidation, Process and Analytical Chemistry, Merck & Co. Inc., 126 E. Lincoln Avenue, Rahway, NJ 07065, USA
| | - Teodor Parella
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, Facultat de Ciències, E-08193 Bellaterra (Barcelona), Catalonia, Spain.
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12
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Timári I, Illyés TZ, Adams RW, Nilsson M, Szilágyi L, Morris GA, Kövér KE. Precise measurement of long-range heteronuclear coupling constants by a novel broadband proton-proton-decoupled CPMG-HSQMBC method. Chemistry 2015; 21:3472-9. [PMID: 25573660 PMCID: PMC4338765 DOI: 10.1002/chem.201405535] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Indexed: 11/17/2022]
Abstract
A broadband proton–proton-decoupled CPMG-HSQMBC method for the precise and direct measurement of long-range heteronuclear coupling constants is presented. The Zangger–Sterk-based homodecoupling scheme reported herein efficiently removes unwanted proton–proton splittings from the heteronuclear multiplets, so that the desired heteronuclear couplings can be determined simply by measuring frequency differences between singlet maxima in the resulting spectra. The proposed pseudo-1D/2D pulse sequences were tested on nucleotides, a metal complex incorporating P heterocycles, and diglycosyl (di)selenides, as well as on other carbohydrate derivatives, for the extraction of nJ(1H,31P), nJ(1H,77Se), and nJ(1H,13C) values, respectively.
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Affiliation(s)
- István Timári
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, 4032 Debrecen (Hungary)
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Castañar L, Saurí J, Williamson RT, Virgili A, Parella T. Pure In-Phase Heteronuclear Correlation NMR Experiments. Angew Chem Int Ed Engl 2014; 53:8379-82. [DOI: 10.1002/anie.201404136] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Indexed: 11/09/2022]
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14
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Castañar L, Saurí J, Williamson RT, Virgili A, Parella T. Pure In-Phase Heteronuclear Correlation NMR Experiments. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201404136] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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15
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Baishya B, Khetrapal CL. "Perfect echo" INEPT: more efficient heteronuclear polarization transfer by refocusing homonuclear J-coupling interaction. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 242:143-154. [PMID: 24650727 DOI: 10.1016/j.jmr.2014.02.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 02/10/2014] [Accepted: 02/12/2014] [Indexed: 06/03/2023]
Abstract
A "perfect echo" based INEPT experiment that demonstrates more efficient heteronuclear polarization transfer over conventional INEPT has been developed. This scheme refocuses the effect of homonuclear (1)H-(1)H J-evolution and simultaneously allows heteronuclear (13)C-(1)H J-evolution to continue during INEPT. This improves one bond heteronuclear polarization transfer efficiency at longer INEPT transfer delays and also enhances the sensitivity of long range INEPT. The refocusing of homonuclear (1)H-(1)H J-coupling could be achieved by doubling the INEPT transfer period leading to a doubling of T2 losses. Therefore, the sensitivity gain is observed when loss of magnetization due to homonuclear (1)H-(1)H J-modulation is more severe than that of T2 decay. However, in general, INEPT transfer period is rather short compared to the longer T2 observed in small molecules. The long range PE-INEPT transfer to carbonyl carbon in beta-butyrolactone, showed much faster build up of C-13 signal than conventional long range INEPT as the long range heteronuclear J-coupling is comparable in magnitude to homonuclear (1)H-(1)H J-coupling in this case. For one bond heteronuclear polarization transfer at shorter delay, PE-INEPT and conventional INEPT displays equal transfer efficiency. Efficient polarization transfer is observed for small molecules dissolved in isotropic as well as weakly aligned media. Further, simulation results obtained using the full propagator and product operator analysis agree well with the experimental observations.
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Affiliation(s)
- Bikash Baishya
- Center of Biomedical Research (Formerly Centre of Biomedical Magnetic Resonance), SGPGIMS Campus, Raebareli Road, Lucknow 226014, India.
| | - C L Khetrapal
- Center of Biomedical Research (Formerly Centre of Biomedical Magnetic Resonance), SGPGIMS Campus, Raebareli Road, Lucknow 226014, India
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16
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Saurí J, Parella T. On the interference of J(HH) modulation in HSQMBC-IPAP and HMBC-IPAP experiments. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2013; 51:509-516. [PMID: 23780917 DOI: 10.1002/mrc.3977] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 03/22/2013] [Accepted: 05/19/2013] [Indexed: 06/02/2023]
Abstract
The effects of phase modulation due to homonuclear proton-proton coupling constants in HSQMBC-IPAP and HMBC-IPAP experiments are experimentally evaluated. We show that accurate values of small proton-carbon coupling constants, (n)J(CH), can be extracted even for phase-distorted cross-peaks obtained from a selHSQMBC experiment applied simultaneously on two mutually J-coupled protons. On the other hand, an assessment of the reliability of (n)J(CH) measurement from distorted cross-peaks obtained in broadband IPAP versions of equivalent HMBC and HSQMBC experiments is also presented. Finally, we show that HMBC-COSY experiments could be an excellent complement to HMBC for the measurement of small (n)J(CH) values.
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Affiliation(s)
- Josep Saurí
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Catalonia, Spain
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17
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Parella T, Espinosa JF. Long-range proton-carbon coupling constants: NMR methods and applications. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 73:17-55. [PMID: 23962883 DOI: 10.1016/j.pnmrs.2013.07.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 07/03/2013] [Accepted: 07/03/2013] [Indexed: 06/02/2023]
Abstract
A general review of novel NMR methods to measure heteronuclear long-range proton-carbon coupling constants ((n)JCH; n>1) in small molecules is made. NMR experiments are classified in terms of NMR pulse scheme and cross-peak nature. A discussion about simplicity, general applicability and accuracy for each particular NMR experiment is presented and exemplified. Important aspects such as the sign determination and measurement of very small coupling values involving protonated and non-protonated carbons as well as the complementarity between different experiments are also discussed. Finally, a compilation of applications in structural and conformational analysis of different types of molecules since 2000 is surveyed.
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Affiliation(s)
- Teodor Parella
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
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18
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Ehni S, Luy B. BEBE(tr) and BUBI: J-compensated concurrent shaped pulses for 1H-13C experiments. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 232:7-17. [PMID: 23673080 DOI: 10.1016/j.jmr.2013.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 03/22/2013] [Accepted: 04/12/2013] [Indexed: 06/02/2023]
Abstract
Shaped pulses designed for broadband excitation, inversion and refocusing are important tools in modern NMR spectroscopy to achieve robust pulse sequences especially in heteronuclear correlation experiments. A large variety of mostly computer-optimized pulse shapes exist for different desired bandwidths, available rf-field strengths, and tolerance to B1-inhomogeneity. They are usually derived for a single spin 1/2, neglecting evolution due to J-couplings. While pulses with constant resulting phase are selfcompensated for heteronuclear coupling evolution as long as they are applied exclusively on a single nucleus, the situation changes for concurrently applied pulse shapes. Using the example of a (1)H,(13)C two spin system, two J-compensated pulse pairs for the application in INEPT-type transfer elements were optimized: a point-to-point pulse sandwich called BEBE(tr), consisting of a broadband excitation and time-reversed excitation pulse, and a combined universal rotation and point-to-point pulse pair called BUBI, which acts as a refocusing pulse on (1)H and a corresponding inversion pulse on (13)C. After a derivation of quality factors and optimization protocols, a theoretical and experimental comparison with conventionally derived BEBOP, BIBOP, and BURBOP-180° pulses is given. While the overall transfer efficiency of a single pulse pair is only reduced by approximately 0.1%, resulting transfer to undesired coherences is reduced by several percent. In experiments this can lead to undesired phase distortions for pairs of uncompensated pulse shapes and even differences in signal intensities of 5-10% in HSQC and up to 68% in more complex COB-HSQC experiments.
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Affiliation(s)
- Sebastian Ehni
- Institute of Organic Chemistry and Institute for Biological Interfaces, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
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19
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Saurí J, Nolis P, Castañar L, Virgili A, Parella T. P.E.HSQMBC: simultaneous measurement of proton-proton and proton-carbon coupling constants. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 224:101-106. [PMID: 23069350 DOI: 10.1016/j.jmr.2012.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 09/10/2012] [Accepted: 09/17/2012] [Indexed: 06/01/2023]
Abstract
A long-range optimized P.E.HSQC experiment, named P.E.HSQMBC, is proposed for the simultaneous measurement of a complete set of homonuclear and heteronuclear coupling constants from a single 2D cross-peak. The sign and the magnitude of proton-proton coupling constants are measured along the direct dimension from the relative E.COSY-type multiplet pattern displacement due to the passive one-bond coupling constant splitting generated in the indirect dimension. On the other hand, long-range proton-carbon coupling constants are independently determined in the detected dimension from a traditional fitting analysis of antiphase multiplet patterns or, more conveniently, from the IPAP multiplet displacement obtained from extended HSQMBC experiments.
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Affiliation(s)
- Josep Saurí
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain
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20
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Furihata K, Tashiro M. Selective COSY-J-resolved-HMBC, a new method for improving sensitivity of cross peaks of methine proton signals attached to a methyl group. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2012; 50:409-414. [PMID: 22528027 DOI: 10.1002/mrc.3816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 03/01/2012] [Accepted: 03/12/2012] [Indexed: 05/31/2023]
Abstract
Improved pulse sequences for measuring long-range C-H coupling constants ((n)J(C-H)), named selective COSY-J-resolved HMBC-1 and -2, have been developed. In the spin systems, such as -CH(C)-CH(A)(CH(3))-CH(B)-, a methine proton H(A) splits into a multiplet owing to several vicinal couplings with protons, resulting in attenuation of its cross-peak intensity. Therefore, the measurements of (n)J(C-H) with H(A) are generally difficult in the J-resolved HMBC or selective J-resolved HMBC spectrum. With the aim of accurate measurements of (n)J(C-H) in such a spin system, we have developed new pulse sequences, which transfer the magnetization of a methyl group to its adjacent methine proton. The proposed pulse sequences successfully enable to enhance the sensitivity of H(A) cross peak in comparison with the selective J-resolved HMBC pulse sequence.
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Affiliation(s)
- Kazuo Furihata
- Division of Agriculture and Agricultural Life Sciences, The University of Tokyo, Tokyo, Japan.
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21
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Espinosa JF, Vidal P, Parella T, Gil S. Measurement of long-range proton-carbon coupling constants from pure in-phase 1D multiplets. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2011; 49:502-507. [PMID: 21751246 DOI: 10.1002/mrc.2782] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 05/19/2011] [Accepted: 05/26/2011] [Indexed: 05/31/2023]
Abstract
The SELective INverse detection of carbon-proton CORrelation pulse sequence that yields a 1D spectrum of a proton directly bonded to a selected carbon resonance has been converted into a proton and carbon double-selective variant that provides a (1)H spectrum of a selected proton that is long-range coupled to a specific carbon resonance. The resulting 1D proton multiplet exhibits a pure absorptive in-phase lineshape for precise measurement of specific long-range proton-carbon coupling constants in small organic molecules at natural abundance.
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Affiliation(s)
- Juan F Espinosa
- Centro de Investigación Lilly, Avda. de la Industria 30, 28108-Alcobendas, Madrid, Spain.
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22
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Kövér KE, Kumar AA, Rusakov YY, Krivdin LB, Illyés TZ, Szilágyi L. Experimental and computational studies of nJ(77Se, 1H) selenium-proton couplings in selenoglycosides. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2011; 49:190-194. [PMID: 21387399 DOI: 10.1002/mrc.2731] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 12/30/2010] [Accepted: 01/10/2011] [Indexed: 05/30/2023]
Abstract
Selenoglycosides are important starting materials in synthetic carbohydrate chemistry and play a role in biological interactions as well. Both aspects are influenced by the conformation around the glycosidic bond. Here, we present a combined experimental and computational approach to measure and evaluate (n)J((77)Se, (1)H) coupling constants for their use in conformational analysis. The measurements were carried out using a modified CPMG-HSQMBC pulse scheme which yields pure absorption antiphase multiplets to allow accurate determination of the (n)J(XH) values regardless of the size of the proton-proton couplings. Theoretical calculations were performed at the Second-Order Polarization Propagator Approach (SOPPA) level. Population-averaged values calculated for geminal and vicinal couplings are in a good agreement with experiment indicating an adequate theoretical level of the calculations. Experimental observations and computations alike have indicated that two-bond (77)Se-(1)H couplings, (2)J((77)Se, (1)H), in a H1-C1-Se-X moiety are very sensitive to the torsion angle around the C1-Se-bond and will, therefore, be useful for conformational studies.
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Affiliation(s)
- Katalin E Kövér
- Department of Chemistry, University of Debrecen, Debrecen, Hungary.
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23
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Boros S, Kövér KE. Low-power composite CPMG HSQMBC experiment for accurate measurement of long-range heteronuclear coupling constants. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2011; 49:106-110. [PMID: 21246626 DOI: 10.1002/mrc.2717] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 11/29/2010] [Accepted: 11/30/2010] [Indexed: 05/30/2023]
Abstract
A modified version of CPMG-HSQMBC pulse scheme is presented for the measurement of long-range heteronuclear coupling constants. The method implements adiabatic inversion and refocusing pulses on the heteronucleus. Low-power composite 180° XY-16 CPMG pulse train is applied on both proton and X nuclei during the evolution of long-range couplings to eliminate phase distortions due to co-evolution of homonuclear proton-proton couplings. The pulse sequence yields pure absorption antiphase multiplets allowing precise and direct measurement of the (n)J(XH) coupling constants regardless from the size of the proton-proton couplings. The applicability of the method is demonstrated using strychnine as a model compound. The selective 1D version of the method is also presented.
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Affiliation(s)
- Sándor Boros
- Chinoin Chemical and Pharmaceutical Works Co. Ltd, Member of sanofi-aventis Group, R&D, Analytical Sciences, Budapest, Hungary.
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24
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Gil S, Espinosa JF, Parella T. IPAP-HSQMBC: measurement of long-range heteronuclear coupling constants from spin-state selective multiplets. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 207:312-321. [PMID: 20952232 DOI: 10.1016/j.jmr.2010.09.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 09/24/2010] [Accepted: 09/24/2010] [Indexed: 05/30/2023]
Abstract
A new NMR approach is proposed for the measurement of long-range heteronuclear coupling constants ((n)J(XH), n>1) in natural abundance molecules. Two complementary in-phase (IP) and anti-phase (AP) data are separately recorded from a modified HSQMBC experiment and then added/subtracted to provide spin-state-selective α/β-HSQMBC spectra. The magnitude of (n)J(XH) can be directly determined by simple analysis of the relative displacement between α- and β-cross-peaks. The robustness of this IPAP-HSQMBC experiment is evaluated experimentally and by simulation using a variety of different conditions. Important aspects such as signal intensity dependence and presence of unwanted cross-talk effects are discussed and examples on the measurement of small proton-carbon ((n)J(CH)) and proton-nitrogen ((n)J(NH)) coupling constants are provided.
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Affiliation(s)
- Sergi Gil
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193-Bellaterra, Barcelona, Spain
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25
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Koskela H, Hakala U, Vanninen P. Structural Characterization of Chemical Warfare Agent Degradation Products in Decontamination Solutions with Proton Band-Selective 1H−31P NMR Spectroscopy. Anal Chem 2010; 82:5331-40. [DOI: 10.1021/ac100867x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Harri Koskela
- VERIFIN, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland
| | - Ullastiina Hakala
- VERIFIN, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland
| | - Paula Vanninen
- VERIFIN, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland
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26
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Kövér KE, Szilágyi L, Batta G, Uhrín D, Jiménez-Barbero J. Biomolecular Recognition by Oligosaccharides and Glycopeptides: The NMR Point of View. COMPREHENSIVE NATURAL PRODUCTS II 2010:197-246. [DOI: 10.1016/b978-008045382-8.00193-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
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27
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Koskela H, Heikkilä O, Kilpeläinen I, Heikkinen S. Quantitative two-dimensional HSQC experiment for high magnetic field NMR spectrometers. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 202:24-33. [PMID: 19853484 DOI: 10.1016/j.jmr.2009.09.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 09/11/2009] [Accepted: 09/26/2009] [Indexed: 05/10/2023]
Abstract
The finite RF power available on carbon channel in proton-carbon correlation experiments leads to non-uniform cross peak intensity response across carbon chemical shift range. Several classes of broadband pulses are available that alleviate this problem. Adiabatic pulses provide an excellent magnetization inversion over a large bandwidth, and very recently, novel phase-modulated pulses have been proposed that perform 90 degrees and 180 degrees magnetization rotations with good offset tolerance. Here, we present a study how these broadband pulses (adiabatic and phase-modulated) can improve quantitative application of the heteronuclear single quantum coherence (HSQC) experiment on high magnetic field strength NMR spectrometers. Theoretical and experimental examinations of the quantitative, offset-compensated, CPMG-adjusted HSQC (Q-OCCAHSQC) experiment are presented. The proposed experiment offers a formidable improvement to the offset performance; (13)C offset-dependent standard deviation of the peak intensity was below 6% in range of+/-20 kHz. This covers the carbon chemical shift range of 150 ppm, which contains the protonated carbons excluding the aldehydes, for 22.3 T NMR magnets. A demonstration of the quantitative analysis of a fasting blood plasma sample obtained from a healthy volunteer is given.
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28
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Wiench JW, Lin VSY, Pruski M. 29Si NMR in solid state with CPMG acquisition under MAS. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 193:233-42. [PMID: 18538601 DOI: 10.1016/j.jmr.2008.05.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 05/08/2008] [Accepted: 05/11/2008] [Indexed: 05/18/2023]
Abstract
A remarkable enhancement of sensitivity can be often achieved in 29Si solid-state NMR by applying the well-known Carr-Purcell-Meiboom-Gill (CPMG) train of rotor-synchronized pi pulses during the detection of silicon magnetization. Here, several one- and two-dimensional (1D and 2D) techniques are used to demonstrate the capabilities of this approach. Examples include 1D 29Si{X} CPMAS spectra and 2D 29Si{X} HETCOR spectra of mesoporous silicas, zeolites and minerals, where X=1H or 27Al. Data processing methods, experimental strategies and sensitivity limits are discussed and illustrated by experiments. The mechanisms of transverse dephasing of 29Si nuclei in solids are analyzed. Fast magic angle spinning, at rates between 25 and 40 kHz, is instrumental in achieving the highest sensitivity gain in some of these experiments. In the case of 29Si-29Si double-quantum techniques, CPMG detection can be exploited to measure homonuclear J-couplings.
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Affiliation(s)
- J W Wiench
- U.S. DOE Ames Laboratory, Iowa State University, Ames, IA 50011, USA
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29
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Enthart A, Freudenberger JC, Furrer J, Kessler H, Luy B. The CLIP/CLAP-HSQC: pure absorptive spectra for the measurement of one-bond couplings. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 192:314-322. [PMID: 18411067 DOI: 10.1016/j.jmr.2008.03.009] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 02/28/2008] [Accepted: 03/18/2008] [Indexed: 05/26/2023]
Abstract
Heteronuclear residual dipolar one-bond couplings of organic molecules at natural abundance are most easily measured using t2 coupled HSQC spectra. However, inevitably mismatched transfer delays result in phase distortions due to residual dispersive antiphase coherences in such experiments. In this article, slightly modified t2 coupled HSQC experiments with clean inphase (CLIP) multiplets are introduced which also reduce the intensities of undesired long-range cross peaks. With the corresponding antiphase (CLAP) experiment, situations where alpha and beta components overlap can be resolved for all multiplicities in an IPAP manner. A comparison of the experiments using hard pulses and shaped broadband excitation and inversion pulses on the heteronucleus is given and potential spectral artefacts are discussed in detail.
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Affiliation(s)
- Andreas Enthart
- Munich Center for Integrated Protein Science, Department Chemie, Organische Chemie II, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany
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30
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Lacerda V, da Silva GVJ, Constantino MG, Dos Santos RB, de Castro EVR, Silva RC. Stereochemistry of cyclopentane derivatives from (2,3)J(CH) dependence on dihedral angle (theta H--C--C--X). MAGNETIC RESONANCE IN CHEMISTRY : MRC 2008; 46:268-273. [PMID: 18236435 DOI: 10.1002/mrc.2182] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The (2,3)J(CH) dependence on dihedral angle (theta H--C--C--X) for cyclopentane derivatives was investigated. We observed that the combined use of experimentally obtained (2,3)J(CH) values and the theoretically determined dihedral angles between the corresponding nuclei can be used to infer the relative stereochemistry of the ring substituents in cyclopentane derivatives. There is a good correlation between the magnitude of (3)J(CH) and the dihedral angle between the hydrogen and the coupled carbon (R2 = 0.88).
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Affiliation(s)
- Valdemar Lacerda
- Departamento de Química, Centro de Ciências Exatas da Universidade Federal do Espirito Santo, Av. Fernando Ferrari 514, 29060-900, Vitória, ES, Brazil.
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31
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Tzvetkova P, Simova S, Luy B. P.E.HSQC: a simple experiment for simultaneous and sign-sensitive measurement of (1JCH+DCH) and (2JHH+DHH) couplings. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 186:193-200. [PMID: 17347001 DOI: 10.1016/j.jmr.2007.02.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 02/09/2007] [Accepted: 02/12/2007] [Indexed: 05/14/2023]
Abstract
The angular information content of residual dipolar couplings between nuclei of fixed distance makes the accurate and sign-sensitive measurement of (1JCH+DCH) and (2JHH+DHH) couplings highly desirable. Experiments published so far are typically highly specialized for the effective measurement of a subset of couplings. The P.E.HSQC presented here, is an E.COSY based experiment which allows the simultaneous measurement of all heteronuclear and homonuclear couplings within CH, CH2, and CH3 groups in a single spectrum with the necessary precision and sign information. The simplicity of the approach and the absence of artefacts like phase distortions due to antiphase evolution make it ideally suited for coupling determination of organic molecules at natural abundance.
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Affiliation(s)
- Pavleta Tzvetkova
- Department Chemie, Organische Chemie II, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany
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32
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Kobzar K, Luy B. Analyses, extensions and comparison of three experimental schemes for measuring ((n)J(CH)+D(CH))-couplings at natural abundance. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 186:131-41. [PMID: 17336556 DOI: 10.1016/j.jmr.2007.02.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Revised: 02/05/2007] [Accepted: 02/05/2007] [Indexed: 05/14/2023]
Abstract
Three types of experiments for measuring (n)J(CH) heteronuclear long-range coupling constants are examined and extended with state-of-the-art pulse sequence building-blocks: The use of a HMBC with corresponding reference-HSQC for accurate coupling determination is combined with the constant time technique and the conversion of antiphase magnetization into ZQ/DQ-coherences; CPMG-based LR-CAHSQC and BIRD(r,X)-HSQMBC experiments are examined in detail with respect to their coherence transfer properties; finally, the HSQC-TOCSY-IPAP experiment is introduced, a sequence derived from previously published alpha and beta selective HSQC-TOCSYs using a different spin state selection technique and a recently developed ZQ-suppression method. The experiments are characterized with their advantages and disadvantages and compared using strychnine and menthol as standard molecules.
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Affiliation(s)
- Kyryl Kobzar
- Department Chemie, Organische Chemie II, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany
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33
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Lacerda V, da Silva GVJ, Constantino MG, Tormena CF, Williamson RT, Marquez BL. Long-range JCH heteronuclear coupling constants in cyclopentane derivatives. Part II. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2007; 45:82-6. [PMID: 17048264 DOI: 10.1002/mrc.1912] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Here we report the detailed measurement of long-range heteronuclear spin-spin coupling constants, especially 2, 3JCH spin-spin couplings for eight different cyclopentane derivatives. These 2, 3JCH constants were shown to be a useful tool in the determination of the relative stereochemistry in these rings. The coupling constant measurements reported here are based on two different experiments: a 2D heteronuclear correlation experiment named G-BIRDR, X-CPMG-HSQMBC and the 2D-coupled gHSQC {1H-13C} experiment
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Affiliation(s)
- Valdemar Lacerda
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901-Ribeirão Preto-SP, Brazil.
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34
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Baskyr I, Brand T, Findeisen M, Berger S. Acquisition Regime for High-Resolution Heteronuclear 2D NMR Spectra. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200603036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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35
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Baskyr I, Brand T, Findeisen M, Berger S. Acquisition Regime for High-Resolution Heteronuclear 2D NMR Spectra. Angew Chem Int Ed Engl 2006; 45:7821-4. [PMID: 17072925 DOI: 10.1002/anie.200603036] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Igor Baskyr
- Institut für Analytische Chemie, Universität Leipzig, Linnéstrasse 3, 04103 Leipzig, Germany
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36
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Nolis P, Pérez M, Parella T. Time-sharing evolution and sensitivity enhancements in 2D HSQC-TOCSY and HSQMBC experiments. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2006; 44:1031-6. [PMID: 16972309 DOI: 10.1002/mrc.1898] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Modifications of time-shared (TS) HSQC-like experiments originally developed by Griesinger and co-workers (Sattler M, Maurer M, Schleucher J, Griesinger C. J. Biomol. NMR 1995; 5: 97) are proposed to extract different types of information from a single NMR pulse scheme. It is shown that simultaneous acquisition of 1H,13C and 1H,15N HSQC-TOCSY and HSQMBC experiments can afford experimental sensitivity enhancements of 20-40% with respect to the separate acquisition of individual 13C or 15N data. In addition, the incorporation of a number of independent editing elements can be easily used for different purposes, for instance, to assign unambiguously 1H, 13C, and 15N chemical shifts, to differentiate directly from relayed cross-peaks, or to measure simultaneously long-range proton-carbon and proton-nitrogen coupling constants. The suggested methodologies can be applied to many different classes of nitrogen-containing compounds and illustrative examples are provided for the peptide cyclosporine as a demonstration of the performance of such experiments.
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Affiliation(s)
- Pau Nolis
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Barcelona, Spain
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37
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Kövér KE, Batta G, Fehér K. Accurate measurement of long-range heteronuclear coupling constants from undistorted multiplets of an enhanced CPMG-HSQMBC experiment. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 181:89-97. [PMID: 16621632 DOI: 10.1016/j.jmr.2006.03.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Revised: 03/15/2006] [Accepted: 03/16/2006] [Indexed: 05/08/2023]
Abstract
Here, we present a modified CPMG-HSQMBC experiment which is capable to reduce the detrimental phase twists in the "long-range" connectivity multiplets caused by proton-proton couplings. We demonstrate that concerted CPMG pulse trains applied on both nuclei in the starting CPMG-INEPT transfer step can considerably be improved by composite pi pulses that compensate for pulse imperfections and off-resonance effects. Experimental optimization of the interpulse delay within the CPMG cycle was found to be crucial in order to achieve the best possible "decoupling" of homonuclear coupling modulation.
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Affiliation(s)
- Katalin E Kövér
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary.
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38
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McNally DJ, Lamoureux M, Li J, Kelly J, Brisson JR, Szymanski CM, Jarrell HC. HR-MAS NMR studies of 15N-labeled cells confirm the structure of the O-methyl phosphoramidate CPS modification in Campylobacter jejuni and provide insight into its biosynthesis. CAN J CHEM 2006. [DOI: 10.1139/v06-028] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Because Campylobacter jejuni is the leading cause of bacterial food-borne gastroenteritis throughout the world, there is intense effort to determine the mechanisms of infectivity associated with this bacterium. Capsular polysaccharide (CPS) has been shown to be an important virulence factor for C. jejuni and a recent study that examined the 11168V26 strain identified several phase-variable CPS modifications including an unusual O-methyl phosphoramidate (MeOPN) group on C-3 of the GalfNAc residue. In this study, we examined the MeOPN group using homo- and hetero-nuclear high-resolution magic angle spinning (HR-MAS) NMR experiments of whole bacterial cells grown on 15NH4Cl-enriched media. 1H31P HSQC NMR experiments showed that the level of 15N labeling within the MeOPN reached 80%, and a large 1J(15N31P) scalar coupling provided direct evidence that confirmed the structure of the MeOPN as CH3OP(O)(NH2)(OR). Because 15N was also detected within the major outer membrane protein as well as the NAc and NGro groups of CPS, ammonium was concluded to be an important building block used in the synthesis of amino acids and glycan structures in C. jejuni. HR-MAS NMR studies of 15N-labeled cells revealed an unanticipated level of complexity as multiple MeOPN signals were observed within 1H-31P HSQC spectra for the 11168V26 and 11168H strains. While some signals originated from the MeOPN at C-3 of GalfNAc, others were attributed to a novel MeOPN located on D-glycero-α-L-gluco-heptopyranose. Together, these HR-MAS NMR findings shed light on nitrogen metabolism in C. jejuni, confirm the chemical structure of the MeOPN, and demonstrate that the modification occurs on both furanose and pyranose CPS sugars for this bacterium.Key words: Campylobacter jejuni, capsular polysaccharide, HR-MAS NMR, isotope labeling, phosphoramidate.
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Lacerda V, da Silva GVJ, Constantino MG, Tormena CF, Williamson RT, Marquez BL. Long-range J(CH) heteronuclear coupling constants in cyclopentane derivatives. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2006; 44:95-8. [PMID: 16281189 DOI: 10.1002/mrc.1723] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Detailed measurements of long-range heteronuclear spin-spin coupling constants, especially (2, 3)J(CH) spin-spin couplings for various cyclopentane derivatives, are reported. The measurements are based on a 2D heteronuclear correlation experiment named G-BIRD(R, X)-CPMG-HSQMBC.
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Affiliation(s)
- Valdemar Lacerda
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901-Ribeirão Preto-SP, Brazil.
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Yip GNB, Zuiderweg ERP. A phase cycle scheme that significantly suppresses offset-dependent artifacts in the R2-CPMG 15N relaxation experiment. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2004; 171:25-36. [PMID: 15504678 DOI: 10.1016/j.jmr.2004.06.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2004] [Revised: 05/19/2004] [Indexed: 05/24/2023]
Abstract
R2-CPMG 15N relaxation experiments form the basis of NMR dynamics measurements, both for analysis of nano-pico second dynamics and milli-micro second dynamics (kinetics). It has been known for some time that in the practical limit of finite pulse widths, which becomes acute when using cryogenic probes, systematic errors in the apparent R2 relaxation behavior occur for spins far off-resonance from the RF carrier. Inaccurate measurement of R2 rates propagates into quantitative models such as model-free relaxation analysis, rotational diffusion tensor analysis, and relaxation dispersion. The root of the problem stems from evolution of the magnetization vectors out of the XY-plane, both during the pulses as well as between the pulses. These deviations vary as a function of pulse length, number of applied CPMG pulses, and CPMG inter-pulse delay. Herein, we analyze these effects in detail with experimentation, numerical simulations, and analytical equations. Our work suggests a surprisingly simple change in the phase progression of the CPMG pulses, which leads to a remarkable improvement in performance. First, the applicability range of the CPMG experiment is increased by a factor of two in spectral width; second, the dynamical/kinetic processes that can be assessed are significantly extended towards the slower time scale; finally, the robustness of the relaxation dispersion experiments is greatly improved.
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Affiliation(s)
- Grover N B Yip
- Department of Chemistry, University of Michigan--Biophysics Research Division 930 N. University Ave, Ann Arbor, MI 48109, USA
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Koskela H, Kilpeläinen I, Heikkinen S. CAGEBIRD: improving the GBIRD filter with a CPMG sequence. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2004; 170:121-126. [PMID: 15324765 DOI: 10.1016/j.jmr.2004.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2003] [Revised: 04/17/2004] [Indexed: 05/24/2023]
Abstract
An improvement of the GBIRD-filter is presented. The current approach utilizes Carr-Purcell-Meiboom-Gill type pulse train during the BIRD delay. The method enables recording of purely absorptive 1D spectrum using only one isotope editing element. In the current method, the parent signal leakage due to JHH evolution during the BIRD delay is considerably smaller than in the conventional approach. As a consequence, the t1-noise is smaller also in 2D applications, such as GBIRD-filtered HSQC.
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Affiliation(s)
- H Koskela
- VERIFIN, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland.
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