Dataset Information

Comprehensive determination of (3)J (HNHalpha) for unfolded proteins using (13)C'-resolved spin-echo difference spectroscopy.

ABSTRACT: An experiment is presented to determine (3)J(HNHalpha) coupling constants, with significant advantages for applications to unfolded proteins. The determination of coupling constants for the peptide chain using 1D (1)H, or 2D and 3D (1)H-(15)N correlation spectroscopy is often hampered by extensive resonance overlap when dealing with flexible, disordered proteins. In the experiment detailed here, the overlap problem is largely circumvented by recording (1)H-(13)C' correlation spectra, which demonstrate superior resolution for unfolded proteins. J-coupling constants are extracted from the peak intensities in a pair of 2D spin-echo difference experiments, affording rapid acquisition of the coupling data. In an application to the cytoplasmic domain of human neuroligin-3 (hNlg3cyt) data were obtained for 78 residues, compared to 54 coupling constants obtained from a 3D HNHA experiment. The coupling constants suggest that hNlg3cyt is intrinsically disordered, with little propensity for structure.

SUBMITTER: Otten R

PROVIDER: S-EPMC2777233 | biostudies-literature | 2009 Dec

REPOSITORIES: biostudies-literature

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Comprehensive determination of (3)J (HNHalpha) for unfolded proteins using (13)C'-resolved spin-echo difference spectroscopy.

Otten Renee R Wood Kathleen K Mulder Frans A A FA

Journal of biomolecular NMR 20091107 4

An experiment is presented to determine (3)J(HNHalpha) coupling constants, with significant advantages for applications to unfolded proteins. The determination of coupling constants for the peptide chain using 1D (1)H, or 2D and 3D (1)H-(15)N correlation spectroscopy is often hampered by extensive resonance overlap when dealing with flexible, disordered proteins. In the experiment detailed here, the overlap problem is largely circumvented by recording (1)H-(13)C' correlation spectra, which demon ...[more]

PMID: 19898942

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Project description:BackgroundCystathionine accumulates selectively in 1p/19q-codeleted gliomas, and can serve as a possible noninvasive biomarker. This study aims to optimize the echo time (TE) of point-resolved spectroscopy (PRESS) for cystathionine detection in gliomas, and evaluate the diagnostic accuracy of PRESS for 1p/19q-codeletion identification.MethodsThe TE of PRESS was optimized with numerical and phantom analysis to better resolve cystathionine from the overlapping aspartate multiplets. The optimized and 97 ms TE PRESS were then applied to 84 prospectively enrolled patients suspected of glioma or glioma recurrence to examine the influence of aspartate on cystathionine quantification by fitting the spectra with and without aspartate. The diagnostic performance of PRESS for 1p/19q-codeleted gliomas were assessed.ResultsThe TE of PRESS was optimized as (TE1, TE2) = (17 ms, 28 ms). The spectral pattern of cystathionine and aspartate were consistent between calculation and phantom. The mean concentrations of cystathionine in vivo fitting without aspartate were significantly higher than those fitting with full basis-set for 97 ms TE PRESS (1.97 ± 2.01 mM vs. 1.55 ± 1.95 mM, p < 0.01), but not significantly different for 45 ms method (0.801 ± 1.217 mM and 0.796 ± 1.217 mM, p = 0.494). The cystathionine concentrations of 45 ms approach was better correlated with those of edited MRS than 97 ms counterparts (r = 0.68 vs. 0.49, both p < 0.01). The sensitivity and specificity for discriminating 1p/19q-codeleted gliomas were 66.7% and 73.7% for 45 ms method, and 44.4% and 52.5% for 97 ms method, respectively.ConclusionThe 45 ms TE PRESS yields more precise cystathionine estimates than the 97 ms method, and is anticipated to facilitate noninvasive diagnosis of 1p/19q-codeleted gliomas, and treatment response monitoring in those patients. Medium diagnostic performance of PRESS for 1p/19q-codeleted gliomas were observed, and warrants further investigations.

Dataset Information

Comprehensive determination of (3)J (HNHalpha) for unfolded proteins using (13)C'-resolved spin-echo difference spectroscopy.

Publications

Comprehensive determination of (3)J (HNHalpha) for unfolded proteins using (13)C'-resolved spin-echo difference spectroscopy.

Similar Datasets

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