Spin dynamics in the carbon-13 nuclear magnetic resonance spectrometric analysis of coal by cross polarization and magic-angle spinning

Sullivan, Mark J.; Maciel, Gary E.

doi:10.1021/ac00246a034

Cited by 138 publications

(51 citation statements)

References 45 publications

(48 reference statements)

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“…The difference between the VCT and VSL intensities is greater for the samples treated at higher temperatures. These results are at odds with some studies on coals, in which T 1r H values determined using VCT and VSL experiments were similar [53,55] The results of linear regression of data from Fig. 3 are shown in Table 1.…”

Section: Vsl and Vct Experimentscontrasting

confidence: 61%

See 1 more Smart Citation

Determination of T1ρH Relaxation Rates in Charred and Uncharred Wood and Consequences for NMR Quantitation

Smernik

Baldock

Oades

et al. 2002

Solid State Nuclear Magnetic Resonance

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Section: Vsl and Vct Experimentscontrasting

confidence: 61%

“…The indirect methods (VCT and VSL) have the disadvantage of low sensitivity for rapidly relaxing components. A limited number of studies have used a combination of two or three of the above methods to give a more complete picture of T 1r H relaxation processes [6,9,26,43,47,51,53,55,56].…”

Section: Resultsmentioning

confidence: 99%

Determination of T1ρH Relaxation Rates in Charred and Uncharred Wood and Consequences for NMR Quantitation

Smernik

Baldock

Oades

et al. 2002

Solid State Nuclear Magnetic Resonance

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“…E. coli strain JM1100 (pPER3) was grown in liquid medium with minimal salts (18) supplemented with glucose (27 mM), L-histidine (80 ,gg/ml), and thymine (20 pg/ml) and containing tetracycline (15 (20,21). These methods will generally yield relaxation rates for protons that are directly bonded to the detected carbon sites (20,21 (22), and has the configuration shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

NMR observation of substrate in the binding site of an active sugar-H+ symport protein in native membranes.

Spooner

Rutherford²,

Watts³

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

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NMR methods have been adopted to observe directly the characteristics of substrate binding to the galactose-H+ symport protein GaIP, in its native environment, the inner membranes of Escherichia coli. Sedimented innermembrane vesicles containing the GaiP protein, overexpressed to levels above 50% of total protein, were analyzed by 13C magic-angle spinning NMR, when in their normal "fluid" state and with incorporated D-[1-'3C]glucose. Using conditions of cross-polarization intended to discriminate bound substrate alone, it was possible to detect as little as 250 nmol of substrate added to the membranes containing about 0.5 Amol (=26 mg) of GalP protein. Such-high measuring sensitivity was possible from the fluid membranes by virtue of their motional contributions to rapid relaxation recovery of the observed nuclei and due to a high-resolution response that approached the static field inhomogeneity in these experiments. This good spectral resolution showed that the native state of the membranes presents a substrate binding environment with high structural homogeneity. Inhibitors of the GaIP protein, cytochalasin B and forskolin, which are specific, and D-galactose, but not L-galactose, prevent or suppress detection of the 13C-labeled glucose substrate, confirming that the observed signal was due to specific interactions with the GalP protein. This specific substrate binding exhibits a preference for the j-anomer of D-glucose and substrate translocation is determined to be slow, on the 10-2 s time scale. The work describes a straightforward NMR approach, which achieves high sensitivity, selectivity, and resolution for nuclei associated with complex membrane proteins and which may be combined with other NMR methodologies to yield additional structural information on the binding site for the current transport system without isolating it from its native membrane environment.

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“…13C-CP MAS NMR spectra were measured with a 2 ms contact 'H spin-lattice relaxation times were determined by a 'H (18Oo),-~-(9O0), pulse sequence followed by cross polarization to 13C magnetization. 16 Overlapping peaks were resolved by using the LAB ONE NMR 1 program (New Methods Research, Inc.) for spectral analysis. Figure 1 shows DSC thermograms of 50/50 (wt/wt) PVA/PHB blends.…”

Section: Nmr Experimentsmentioning

confidence: 99%

Crystallization and compatibility of poly(vinyl alcohol)/poly(3‐hydroxybutyrate) blends: Influence of blend composition and tacticity of poly(vinyl alcohol)

Yoshie

Azuma

Sakurai

et al. 1995

J of Applied Polymer Sci

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SYNOPSISCompatibility of a crystalline/crystalline polymer blend, poly(viny1 alcohol) (PVA)/poly(3-hydroxybutyrate) (PHB), was studied by high-resolution solid-state 13C-NMR spectroscopy.The 'H T1 measurement demonstrated that both the compatibility and the domain size depend on the composition of the blend. The PVA/PHB blend is compatible only when the blend contains a large amount of PVA. The domain sizes of the compatible blend are less than 200 A. In the pulse saturation transfer (PST) MAS NMR spectra, the carbonyl carbon resonance from PHB showed a downfield shift, which indicates that the compatibility of the PVA/PHB blends is due to the hydrogen-bonding interaction in the amorphous phase. The DSC measurement showed that the compatible blends adopt low crystallinity for both PHB and PVA. The crystallization in these blends is likely to be disturbed by the hydrogen-bonding interaction in the amorphous phase. The compatibility of PVA/PHB is also affected by the tacticity of PVA. The compatible composition range of the syndiotacticrich PVA/PHB blend is wider than that of the atactic-PVA/PHB blend. It is likely that the capacity to form the hydrogen bond depends on the tacticity of PVA. 0 1995

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Spin dynamics in the carbon-13 nuclear magnetic resonance spectrometric analysis of coal by cross polarization and magic-angle spinning

Cited by 138 publications

References 45 publications

Determination of T1ρH Relaxation Rates in Charred and Uncharred Wood and Consequences for NMR Quantitation

Determination of T1ρH Relaxation Rates in Charred and Uncharred Wood and Consequences for NMR Quantitation

NMR observation of substrate in the binding site of an active sugar-H+ symport protein in native membranes.

Crystallization and compatibility of poly(vinyl alcohol)/poly(3‐hydroxybutyrate) blends: Influence of blend composition and tacticity of poly(vinyl alcohol)

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