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Vladimir A. Mandelshtam - One of the best experts on this subject based on the ideXlab platform.
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Chapter 4:The Filter Diagonalization Method
New Developments in NMR, 2017Co-Authors: A.j. Shaka, Vladimir A. MandelshtamAbstract:The Filter Diagonalization Method (FDM) is an elegant and numerically efficient algorithm of spectral estimation. It shows advantages over conventional Fourier transform spectra when the signal-to-noise ratio is adequate, and the true spectrum would be well resolved. Isolated narrow resonances can be captured quite accurately using FDM, even if the time-domain sampling is insufficient to give anything like the true line width by FT. As a true multi-variate Method it becomes especially advantageous when applied to multi-dimensional spectra. We hope this chapter will offer a glimpse into the math and science behind Filter Diagonalization, and make the Method more ubiquitous.
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the filter Diagonalization Method and its assessment for fourier transform mass spectrometry
International Journal of Mass Spectrometry, 2014Co-Authors: Beau R Martini, Konstantin Aizikov, Vladimir A. MandelshtamAbstract:Abstract Application of the filter Diagonalization Method (FDM) to Fourier transform mass spectrometry (FTMS) data is not new. Under certain conditions FDM provides resolution superior to Fourier transform (FT) and was proved to be useful in investigation of space charge phenomena in an ion cyclotron resonance cell (ICR) by O’Connor and Amster research groups. Kozhinov and Tsybin have reported substantial increase in resolution and/or acquisition speed of high-resolution molecular and macromolecular MS data. In light of fundamental difficulty in providing theoretical evaluation of the FDM performance under various spectral and noise conditions, this paper is an empirical investigation aimed at establishing the Method's true potentials and areas where it may perform better than currently used technologies. The study was conducted on both synthetic transients and experimental Orbitrap transients. Unlike FT, resolution of FDM depends strongly on noise levels. Consequently, we identify the regimes at which FDM can provide a superior resolution even at moderate signal to noise ratios. Moreover, when individual peaks fail to be resolved either because of the small peak separation or high noise conditions, the FDM solution seems to preserve their cumulative intensity. This preservation of the true intensity seems to be very consistent across rather wide ranges of noise conditions and almost impervious to the peak separation.
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filter Diagonalization Method for processing pfg nmr data
Journal of Magnetic Resonance, 2013Co-Authors: Beau R Martini, Vladimir A. Mandelshtam, Gareth A Morris, Adam A Colbourne, Mathias NilssonAbstract:Obtaining diffusion coefficients from PFG NMR diffusion (a.k.a DOSY) data is, in the general case, an ill-posed problem. Numerous Methods for processing such data have therefore been developed, each with different constraints and assumptions. The Regularized Resolvent Transform (RRT) is a proven and robust Method for spectral inversion. In earlier papers RRT, albeit very slow, was argued to be superior for DOSY processing to a related algorithm, the Filter Diagonalization Method (FDM). Here FDM is revisited and a new regularization Method is implemented, which drastically improves the performance and provides spectra of comparable or better quality to those provided by RRT. Both the RRT and the FDM for DOSY processing have been implemented as options in the free and open source DOSY Toolbox.
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rapid high resolution four dimensional nmr spectroscopy using the filter Diagonalization Method and its advantages for detailed structural elucidation of oligosaccharides
Journal of Magnetic Resonance, 2005Co-Authors: Geoffrey S. Armstrong, A.j. Shaka, Vladimir A. Mandelshtam, Brad BendiakAbstract:Abstract Four-dimensional nuclear magnetic resonance spectroscopy with high resolution of signals in the indirect dimensions is reported as an implementation of the filter Diagonalization Method (FDM). Using an oligosaccharide derivatized with 13 C-labeled acetyl isotags, a four-dimensional constant-time pulse sequence was tailored for conjoint use with the FDM. Results demonstrate that high resolution in all dimensions can be achieved using a relatively short experimental time period (19 h), even though the spectrum is highly congested in the direct and all three indirect dimensions. The combined use of isotags, constant-time pulse sequences, and FDM permits rapid isolation of sugar ring proton spin systems in multiple dimensions and enables all endocyclic J -couplings to be simply measured, the key goal to assigning sugar stereochemistry and anomeric configuration. A general Method for rapid, unambiguous elucidation of spin systems in oligosaccharides has been a long-sought goal of carbohydrate NMR, and isotags combined with the FDM now enable this to be easily performed. Additional general advantages of the FDM program for generating high-resolution 2D slices in any dimension from a 4D spectrum are emphasized.
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rapid 3d nmr using the filter Diagonalization Method application to oligosaccharides derivatized with 13c labeled acetyl groups
Journal of Magnetic Resonance, 2004Co-Authors: Geoffrey S. Armstrong, A.j. Shaka, Vladimir A. Mandelshtam, Kristin E Cano, Brad BendiakAbstract:Abstract Rapid 3D NMR spectroscopy of oligosaccharides having isotopically labeled acetyl “isotags” was made possible with high resolution in the indirect dimensions using the filter Diagonalization Method (FDM). A pulse sequence was designed for the optimal correlation of acetyl methyl protons, methyl carbons, and carbonyl carbons. The multi-dimensional nature of the FDM, coupled with the advantages of constant-time evolution periods, resulted in marked improvements over Fourier transform (FT) and mirror-image linear prediction (MI-LP) processing Methods. The three Methods were directly compared using identical data sets. A highly resolved 3D spectrum was achieved with the FDM using a very short experimental time (28 min).
A.j. Shaka - One of the best experts on this subject based on the ideXlab platform.
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Chapter 4:The Filter Diagonalization Method
New Developments in NMR, 2017Co-Authors: A.j. Shaka, Vladimir A. MandelshtamAbstract:The Filter Diagonalization Method (FDM) is an elegant and numerically efficient algorithm of spectral estimation. It shows advantages over conventional Fourier transform spectra when the signal-to-noise ratio is adequate, and the true spectrum would be well resolved. Isolated narrow resonances can be captured quite accurately using FDM, even if the time-domain sampling is insufficient to give anything like the true line width by FT. As a true multi-variate Method it becomes especially advantageous when applied to multi-dimensional spectra. We hope this chapter will offer a glimpse into the math and science behind Filter Diagonalization, and make the Method more ubiquitous.
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phase sensitive spectral estimation by the hybrid filter Diagonalization Method
Journal of Magnetic Resonance, 2012Co-Authors: Hasan Celik, Clark D Ridge, A.j. ShakaAbstract:Abstract A more robust way to obtain a high-resolution multidimensional NMR spectrum from limited data sets is described. The Filter Diagonalization Method (FDM) is used to analyze phase-modulated data and cast the spectrum in terms of phase-sensitive Lorentzian “phase-twist” peaks. These spectra are then used to obtain absorption-mode phase-sensitive spectra. In contrast to earlier implementations of multidimensional FDM, the absolute phase of the data need not be known beforehand, and linear phase corrections in each frequency dimension are possible, if they are required. Regularization is employed to improve the conditioning of the linear algebra problems that must be solved to obtain the spectral estimate. While regularization smoothes away noise and small peaks, a hybrid Method allows the true noise floor to be correctly represented in the final result. Line shape transformation to a Gaussian-like shape improves the clarity of the spectra, and is achieved by a conventional Lorentzian-to-Gaussian transformation in the time-domain, after inverse Fourier transformation of the FDM spectra. The results obtained highlight the danger of not using proper phase-sensitive line shapes in the spectral estimate. The advantages of the new Method for the spectral estimate are the following: (i) the spectrum can be phased by conventional means after it is obtained; (ii) there is a true and accurate noise floor; and (iii) there is some indication of the quality of fit in each local region of the spectrum. The Method is illustrated with 2D NMR data for the first time, but is applicable to n-dimensional data without any restriction on the number of time/frequency dimensions.
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ersatz and hybrid nmr spectral estimates using the filter Diagonalization Method
Journal of Physical Chemistry A, 2009Co-Authors: Clark D Ridge, A.j. ShakaAbstract:The filter Diagonalization Method (FDM) is an efficient and elegant way to make a spectral estimate purely in terms of Lorentzian peaks. As NMR spectral peaks of liquids conform quite well to this model, the FDM spectral estimate can be accurate with far fewer time domain points than conventional discrete Fourier transform (DFT) processing. However, noise is not efficiently characterized by a finite number of Lorentzian peaks, or by any other analytical form, for that matter. As a result, noise can affect the FDM spectrum in different ways than it does the DFT spectrum, and the effect depends on the dimensionality of the spectrum. Regularization to suppress (or control) the influence of noise to give an “ersatz”, or EFDM, spectrum is shown to sometimes miss weak features, prompting a more conservative implementation of filter Diagonalization. The spectra obtained, called “hybrid” or HFDM spectra, are acquired by using regularized FDM to obtain an “infinite time” spectral estimate and then adding to it the...
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enhanced spectral resolution by high dimensional nmr using the filter Diagonalization Method and hidden dimensions
Journal of Magnetic Resonance, 2009Co-Authors: Xi Meng, Clark D Ridge, Bao D Nguyen, A.j. ShakaAbstract:Abstract High-dimensional (HD) NMR spectra have poorer digital resolution than low-dimensional (LD) spectra, for a fixed amount of experiment time. This has led to “reduced-dimensionality” strategies, in which several LD projections of the HD NMR spectrum are acquired, each with higher digital resolution; an approximate HD spectrum is then inferred by some means. We propose a strategy that moves in the opposite direction, by adding more time dimensions to increase the information content of the data set, even if only a very sparse time grid is used in each dimension. The full HD time-domain data can be analyzed by the filter Diagonalization Method (FDM), yielding very narrow resonances along all of the frequency axes, even those with sparse sampling. Integrating over the added dimensions of HD FDM NMR spectra reconstitutes LD spectra with enhanced resolution, often more quickly than direct acquisition of the LD spectrum with a larger number of grid points in each of the fewer dimensions. If the extra-dimensions do not appear in the final spectrum, and are used solely to boost information content, we propose the moniker hidden-dimension NMR. This work shows that HD peaks have unmistakable frequency signatures that can be detected as single HD objects by an appropriate algorithm, even though their patterns would be tricky for a human operator to visualize or recognize, and even if digital resolution in an HD FT spectrum is very coarse compared with natural line widths.
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rapid high resolution four dimensional nmr spectroscopy using the filter Diagonalization Method and its advantages for detailed structural elucidation of oligosaccharides
Journal of Magnetic Resonance, 2005Co-Authors: Geoffrey S. Armstrong, A.j. Shaka, Vladimir A. Mandelshtam, Brad BendiakAbstract:Abstract Four-dimensional nuclear magnetic resonance spectroscopy with high resolution of signals in the indirect dimensions is reported as an implementation of the filter Diagonalization Method (FDM). Using an oligosaccharide derivatized with 13 C-labeled acetyl isotags, a four-dimensional constant-time pulse sequence was tailored for conjoint use with the FDM. Results demonstrate that high resolution in all dimensions can be achieved using a relatively short experimental time period (19 h), even though the spectrum is highly congested in the direct and all three indirect dimensions. The combined use of isotags, constant-time pulse sequences, and FDM permits rapid isolation of sugar ring proton spin systems in multiple dimensions and enables all endocyclic J -couplings to be simply measured, the key goal to assigning sugar stereochemistry and anomeric configuration. A general Method for rapid, unambiguous elucidation of spin systems in oligosaccharides has been a long-sought goal of carbohydrate NMR, and isotags combined with the FDM now enable this to be easily performed. Additional general advantages of the FDM program for generating high-resolution 2D slices in any dimension from a 4D spectrum are emphasized.
Brad Bendiak - One of the best experts on this subject based on the ideXlab platform.
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High-resolution pyrimidine- and ribose-specific 4D HCCH-COSY spectra of RNA using the filter Diagonalization Method
Journal of Biomolecular NMR, 2008Co-Authors: Justin T. Douglas, Geoffrey S. Armstrong, Brad Bendiak, Michael P. Latham, Arthur PardiAbstract:The NMR spectra of nucleic acids suffer from severe peak overlap, which complicates resonance assignments. 4D NMR experiments can overcome much of the degeneracy in 2D and 3D spectra; however, the linear increase in acquisition time with each new dimension makes it impractical to acquire high-resolution 4D spectra using standard Fourier transform (FT) techniques. The filter Diagonalization Method (FDM) is a numerically efficient algorithm that fits the entire multi-dimensional time-domain data to a set of multi-dimensional oscillators. Selective 4D constant-time HCCH-COSY experiments that correlate the H5–C5–C6–H6 base spin systems of pyrimidines or the H1′–C1′–C2′–H2′ spin systems of ribose sugars were acquired on the ^13C-labeled iron responsive element (IRE) RNA. FDM-processing of these 4D experiments recorded with only 8 complex points in the indirect dimensions showed superior spectral resolution than FT-processed spectra. Practical aspects of obtaining optimal FDM-processed spectra are discussed. The results here demonstrate that FDM-processing can be used to obtain high-resolution 4D spectra on a medium sized RNA in a fraction of the acquisition time normally required for high-resolution, high-dimensional spectra.
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high resolution four dimensional carbon correlated 1h 1h roesy experiments employing isotags and the filter Diagonalization Method for effective assignment of glycosidic linkages in oligosaccharides
Journal of Magnetic Resonance, 2006Co-Authors: Geoffrey S. Armstrong, Brad BendiakAbstract:Abstract Four-dimensional nuclear magnetic resonance spectroscopy of oligosaccharides that correlates 1 H– 1 H ROESY cross peaks to two additional 13 C frequency dimensions is reported. The 13 C frequencies were introduced by derivatization of all free hydroxyl groups with doubly 13 C-labeled acetyl isotags. Pulse sequences were optimized for processing with the filter Diagonalization Method. The extensive overlap typically observed in 2D ROESY 1 H– 1 H planes was alleviated by resolution of ROESY cross peaks in the two added dimensions associated with the carbon frequencies of the isotags. This enabled the interresidue 1 H– 1 H ROESY cross peaks to be unambiguously assigned hence spatially proximate sugar spin systems across glycosidic bonds could be effectively ascertained. An experiment that selectively amplifies interresidue ROESY 1 H– 1 H cross peaks is also reported. It moves the magnetization of an intraresidue proton normally correlated to a sugar H-1 signal orthogonally along the z axis prior to a Tr-ROESY mixing sequence. This virtually eliminates the incoherent intraresidue ROESY transfer, suppresses coherent TOCSY transfer, and markedly enhances the intensity of interresidue ROESY cross peaks.
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The single basis filter Diagonalization Method: A rapid multidimensional data processing scheme
Journal of Magnetic Resonance, 2005Co-Authors: Geoffrey S. Armstrong, Brad BendiakAbstract:Abstract A new way to apply the filter Diagonalization Method (FDM) that results in a large increase in the speed of calculation of multidimensional NMR spectra is presented. The speed increase is accompanied by slight differences in spectral lineshapes, although frequency estimates remain essentially identical. For contoured spectra, the Method does not result in appreciable differences from the full FDM calculation. Optimal parameter sets for an FDM calculation can be estimated far more rapidly, which makes the FDM more straightforward to employ in practice. The performance of the Method versus the full FDM was investigated for both model and experimental signals. The effect of noise on the Method was also studied.
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rapid high resolution four dimensional nmr spectroscopy using the filter Diagonalization Method and its advantages for detailed structural elucidation of oligosaccharides
Journal of Magnetic Resonance, 2005Co-Authors: Geoffrey S. Armstrong, A.j. Shaka, Vladimir A. Mandelshtam, Brad BendiakAbstract:Abstract Four-dimensional nuclear magnetic resonance spectroscopy with high resolution of signals in the indirect dimensions is reported as an implementation of the filter Diagonalization Method (FDM). Using an oligosaccharide derivatized with 13 C-labeled acetyl isotags, a four-dimensional constant-time pulse sequence was tailored for conjoint use with the FDM. Results demonstrate that high resolution in all dimensions can be achieved using a relatively short experimental time period (19 h), even though the spectrum is highly congested in the direct and all three indirect dimensions. The combined use of isotags, constant-time pulse sequences, and FDM permits rapid isolation of sugar ring proton spin systems in multiple dimensions and enables all endocyclic J -couplings to be simply measured, the key goal to assigning sugar stereochemistry and anomeric configuration. A general Method for rapid, unambiguous elucidation of spin systems in oligosaccharides has been a long-sought goal of carbohydrate NMR, and isotags combined with the FDM now enable this to be easily performed. Additional general advantages of the FDM program for generating high-resolution 2D slices in any dimension from a 4D spectrum are emphasized.
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rapid 3d nmr using the filter Diagonalization Method application to oligosaccharides derivatized with 13c labeled acetyl groups
Journal of Magnetic Resonance, 2004Co-Authors: Geoffrey S. Armstrong, A.j. Shaka, Vladimir A. Mandelshtam, Kristin E Cano, Brad BendiakAbstract:Abstract Rapid 3D NMR spectroscopy of oligosaccharides having isotopically labeled acetyl “isotags” was made possible with high resolution in the indirect dimensions using the filter Diagonalization Method (FDM). A pulse sequence was designed for the optimal correlation of acetyl methyl protons, methyl carbons, and carbonyl carbons. The multi-dimensional nature of the FDM, coupled with the advantages of constant-time evolution periods, resulted in marked improvements over Fourier transform (FT) and mirror-image linear prediction (MI-LP) processing Methods. The three Methods were directly compared using identical data sets. A highly resolved 3D spectrum was achieved with the FDM using a very short experimental time (28 min).
Nimrod Moiseyev - One of the best experts on this subject based on the ideXlab platform.
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bound and resonance states by a time independent filter Diagonalization Method for large hamiltonian systems
Chemical Physics Letters, 1999Co-Authors: Mercedes Alacid, Claude Leforestier, Nimrod MoiseyevAbstract:Abstract A new algorithm on the basis of Neuhauser–Mandelshtam–Taylor developments of the filter Diagonalization Method is proposed for calculating highly excited bound states and resonances for large Hamiltonian systems, even in the high-density-state part of the spectrum. This is a complementary Method to the Lanczos procedure with no reorthogonalization which is widely used for calculating the low lying energy levels, i.e. the low-density part of the spectrum. An illustrative numerical example is given.
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Selective Quasienergies from Short Time Cross-Correlation Probability Amplitudes by the Filter-Diagonalization Method
Physical Review E, 1998Co-Authors: Markus Glück, H. Jürgen Korsch, Nimrod MoiseyevAbstract:The Filter-Diagonalization Method is applied to time periodic Hamiltonians and used to find selectively the regular and chaotic quasienergies of a driven 2D rotor. The use of N cross-correlation probability amplitudes enables a selective calculation of the quasienergies from short time propagation to the time T (N). Compared to the propagation time T (1) which is required for resolving the quasienergy spectrum with the same accuracy from auto-correlation calculations, the cross-correlation time T (N) is shorter by the factor N , that is T (1) = N T (N).
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vibrationally resolved spectra from short time quantum molecular dynamics by the filter Diagonalization Method
Chemical Physics Letters, 1997Co-Authors: Pavel Jungwirth, Burkhard Schmidt, Nimrod MoiseyevAbstract:The possibility of calculating vibrationally resolved spectra from short numerically exact and approximate quantum dynamical propagations using the new filter-Diagonalization Method is explored. The benchmark process under study concerns electron photodetachment in the I y Ar complex. Comparison with results obtained from long-time propagations 2 and with experiment reveals the power of the filter-Diagonalization scheme. Using the new Methodology it now becomes possible to extract positions of spectral peaks for large polyatomic systems from approximate quantum propagations e.g., by means of the recently developed classical separable potential approach. q 1997 Elsevier Science B.V.
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Resonances from short time complex-scaled cross-correlation probability amplitudes by the filter-Diagonalization Method
Chemical Physics Letters, 1997Co-Authors: Edvardas Narevicius, Daniel Neuhauser, H. Jürgen Korsch, Nimrod MoiseyevAbstract:Abstract The filter-Diagonalization Method is used to find the broad and even overlapping resonances of a 1D Hamiltonian used before as a test model for new resonance theories and computational Methods. Is is found that the use of several complex-scaled cross-correlation probability amplitudes from short-time propagation enables the calculation of broad overlapping resonances, which can not be resolved from the amplitude of a single complex-scaled autocorrelation calculation.
Geoffrey S. Armstrong - One of the best experts on this subject based on the ideXlab platform.
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High-resolution pyrimidine- and ribose-specific 4D HCCH-COSY spectra of RNA using the filter Diagonalization Method
Journal of Biomolecular NMR, 2008Co-Authors: Justin T. Douglas, Geoffrey S. Armstrong, Brad Bendiak, Michael P. Latham, Arthur PardiAbstract:The NMR spectra of nucleic acids suffer from severe peak overlap, which complicates resonance assignments. 4D NMR experiments can overcome much of the degeneracy in 2D and 3D spectra; however, the linear increase in acquisition time with each new dimension makes it impractical to acquire high-resolution 4D spectra using standard Fourier transform (FT) techniques. The filter Diagonalization Method (FDM) is a numerically efficient algorithm that fits the entire multi-dimensional time-domain data to a set of multi-dimensional oscillators. Selective 4D constant-time HCCH-COSY experiments that correlate the H5–C5–C6–H6 base spin systems of pyrimidines or the H1′–C1′–C2′–H2′ spin systems of ribose sugars were acquired on the ^13C-labeled iron responsive element (IRE) RNA. FDM-processing of these 4D experiments recorded with only 8 complex points in the indirect dimensions showed superior spectral resolution than FT-processed spectra. Practical aspects of obtaining optimal FDM-processed spectra are discussed. The results here demonstrate that FDM-processing can be used to obtain high-resolution 4D spectra on a medium sized RNA in a fraction of the acquisition time normally required for high-resolution, high-dimensional spectra.
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high resolution four dimensional carbon correlated 1h 1h roesy experiments employing isotags and the filter Diagonalization Method for effective assignment of glycosidic linkages in oligosaccharides
Journal of Magnetic Resonance, 2006Co-Authors: Geoffrey S. Armstrong, Brad BendiakAbstract:Abstract Four-dimensional nuclear magnetic resonance spectroscopy of oligosaccharides that correlates 1 H– 1 H ROESY cross peaks to two additional 13 C frequency dimensions is reported. The 13 C frequencies were introduced by derivatization of all free hydroxyl groups with doubly 13 C-labeled acetyl isotags. Pulse sequences were optimized for processing with the filter Diagonalization Method. The extensive overlap typically observed in 2D ROESY 1 H– 1 H planes was alleviated by resolution of ROESY cross peaks in the two added dimensions associated with the carbon frequencies of the isotags. This enabled the interresidue 1 H– 1 H ROESY cross peaks to be unambiguously assigned hence spatially proximate sugar spin systems across glycosidic bonds could be effectively ascertained. An experiment that selectively amplifies interresidue ROESY 1 H– 1 H cross peaks is also reported. It moves the magnetization of an intraresidue proton normally correlated to a sugar H-1 signal orthogonally along the z axis prior to a Tr-ROESY mixing sequence. This virtually eliminates the incoherent intraresidue ROESY transfer, suppresses coherent TOCSY transfer, and markedly enhances the intensity of interresidue ROESY cross peaks.
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The single basis filter Diagonalization Method: A rapid multidimensional data processing scheme
Journal of Magnetic Resonance, 2005Co-Authors: Geoffrey S. Armstrong, Brad BendiakAbstract:Abstract A new way to apply the filter Diagonalization Method (FDM) that results in a large increase in the speed of calculation of multidimensional NMR spectra is presented. The speed increase is accompanied by slight differences in spectral lineshapes, although frequency estimates remain essentially identical. For contoured spectra, the Method does not result in appreciable differences from the full FDM calculation. Optimal parameter sets for an FDM calculation can be estimated far more rapidly, which makes the FDM more straightforward to employ in practice. The performance of the Method versus the full FDM was investigated for both model and experimental signals. The effect of noise on the Method was also studied.
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rapid high resolution four dimensional nmr spectroscopy using the filter Diagonalization Method and its advantages for detailed structural elucidation of oligosaccharides
Journal of Magnetic Resonance, 2005Co-Authors: Geoffrey S. Armstrong, A.j. Shaka, Vladimir A. Mandelshtam, Brad BendiakAbstract:Abstract Four-dimensional nuclear magnetic resonance spectroscopy with high resolution of signals in the indirect dimensions is reported as an implementation of the filter Diagonalization Method (FDM). Using an oligosaccharide derivatized with 13 C-labeled acetyl isotags, a four-dimensional constant-time pulse sequence was tailored for conjoint use with the FDM. Results demonstrate that high resolution in all dimensions can be achieved using a relatively short experimental time period (19 h), even though the spectrum is highly congested in the direct and all three indirect dimensions. The combined use of isotags, constant-time pulse sequences, and FDM permits rapid isolation of sugar ring proton spin systems in multiple dimensions and enables all endocyclic J -couplings to be simply measured, the key goal to assigning sugar stereochemistry and anomeric configuration. A general Method for rapid, unambiguous elucidation of spin systems in oligosaccharides has been a long-sought goal of carbohydrate NMR, and isotags combined with the FDM now enable this to be easily performed. Additional general advantages of the FDM program for generating high-resolution 2D slices in any dimension from a 4D spectrum are emphasized.
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rapid 3d nmr using the filter Diagonalization Method application to oligosaccharides derivatized with 13c labeled acetyl groups
Journal of Magnetic Resonance, 2004Co-Authors: Geoffrey S. Armstrong, A.j. Shaka, Vladimir A. Mandelshtam, Kristin E Cano, Brad BendiakAbstract:Abstract Rapid 3D NMR spectroscopy of oligosaccharides having isotopically labeled acetyl “isotags” was made possible with high resolution in the indirect dimensions using the filter Diagonalization Method (FDM). A pulse sequence was designed for the optimal correlation of acetyl methyl protons, methyl carbons, and carbonyl carbons. The multi-dimensional nature of the FDM, coupled with the advantages of constant-time evolution periods, resulted in marked improvements over Fourier transform (FT) and mirror-image linear prediction (MI-LP) processing Methods. The three Methods were directly compared using identical data sets. A highly resolved 3D spectrum was achieved with the FDM using a very short experimental time (28 min).