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A method for the acquisition of localized 2D shift-correlated spectra, based on the combination of the stimulated-echo volume-selection and gradient-enhanced COSY experiments, is described. The sequence can be modified to perform a number of localized experiments including HOHAHA and DQF-COSY. The method is demonstrated in vivo by presentation of localized(More)
In vivo, volume-selected 1H NMR spectroscopy employing the SPACE technique was used to monitor biochemical changes in the thiamin deficient rat brain in response to glucose loading. The concentrations of brain N-acetylaspartate, glutamate/glutamine/gamma-aminobutyric acid, lactate and glucose differed significantly from those of control animals. The results(More)
In vivo high resolution volume-selected 1H magnetic resonance spectroscopy of human tibia has been undertaken using spatial coordinates obtained from magnetic resonance images. Adult tibial marrow has a 1H spectrum rich in fatty acid resonances and is readily distinguished from the 1H spectra of surrounding leg muscle. In all four leukemic patients(More)
Chemical synthesis was used to prepare the HIV-1 protease specifically 13C-labelled in the catalytically essential Asp 25 in each monomer. The NMR chemical shift of the 13C-enriched homodimeric enzyme was measured in the presence of the inhibitor pepstatin, a mimic of the tetrahedral intermediate formed in enzyme catalysis. In this complex, the catalytic(More)
Seven cysteine-rich repeats form the ligand-binding region of the low-density lipoprotein (LDL) receptor. Each of these repeats is assumed to bind a calcium ion, which is needed for association of the receptor with its ligands, LDL and beta-VLDL. The effects of metal ions on the folding of the reduced N-terminal cysteine-rich repeat have been examined by(More)
Volume-selected 1H NMR spectroscopy was combined with spectral editing to selectively detect brain metabolites. The SPACE localization sequence was used to create a voxel of zeta-magnetization which could then be edited for any scalar coupled metabolite by the use of selective excitation in the ECZOTIC sequence to generate longitudinal spin order. The(More)
Circular dichroism and NMR spectroscopy have been used to determine the structure of the low-density lipoprotein (LDL) receptor-binding peptide, comprising residues 130-152, of the human apolipoprotein E. This peptide has little persistent three-dimensional structure in solution, but when bound to micelles of dodecylphosphocholine (DPC) it adopts a(More)
The ligand-binding domain of the human low-density lipoprotein receptor consists of seven modules, each of 40-45 residues. In the presence of calcium, these modules adopt a common polypeptide fold with three conserved disulfide bonds. A concatemer of the first and second modules (LB(1-2)) folds efficiently in the presence of calcium ions, forming the same(More)
A method (NIMBLE) for obtaining optimum B0 field homogeneity at voxels located away from the magnet isocenter for use in volume-selected NMR spectroscopy is described. Voxels may be shimmed using only first-order X, Y, and Z shims to produce three-dimensional shim current maps, thus avoiding shim coupling problems. NIMBLE shimming prior to volume selection(More)
The combination of a frequency nonselective excitation suppression method (1331 sequence) with selective excitation followed by gradient-induced dephasing of water transverse magnetization yielded suppression ratios of greater than 10,000:1. The need for gradient preemphasis and correction of B0 field shifts is discussed. The suppression efficiency of this(More)