WET, a T1- and B1-Insensitive Water-Suppression Method for in Vivo Localized 1H NMR Spectroscopy

Ogg, Robert J.; Kingsley, Peter B.; Taylor, Judy

doi:10.1006/jmrb.1994.1048

Cited by 676 publications

(553 citation statements)

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“…3B shows the relative positioning in the NMR and crystal structures of these and other side chains that have been implicated as important for PAI-1 binding to vitronectin. As shown in the figure, five residues previously identified to participate in PAI-1 binding (Thr 10 , Glu 23 , Leu 24 , Tyr 27 , and Tyr 28 ) occupy the same positions. Differences are observed for the relative orientation of Gly 12 , Phe 13 , Asp 22 , and Asp 34 in the two structures.…”

Section: Figmentioning

confidence: 76%

“…Best resolution was obtained at pH 4.4, and all the assignments were reported with respect to the spectra obtained at pH 4.4 and 298 K. Two-dimensional NMR data were acquired in phase-sensitive mode using the States-Haberkorn (22) method for quadrature detection in the indirect dimension. Spectra of SMB in H 2 O were recorded by using WET (23,24) or WATERGATE sequences (25) for water suppression. Two-dimensional homonuclear NOESY (26) spectra were recorded with mixing times of 150, 200, and 250 ms. TOCSY spectra (27) were recorded using DIPSI spin-lock sequence with a 8 kHz radio frequency field and mixing times of 15, 30, 60, and 80 ms.…”

Section: Methodsmentioning

confidence: 99%

“…As shown in more detail in the space-filling representation of the SMB domain presented in Fig. 4A, these residues appear to form a PAI-1-binding surface that encompasses two contiguous regions; the first region includes Gly 12 , Phe 13 , and Thr 10 , and the second contains Asp 22 , Glu 23 , Leu 24 , Tyr 27 , and Tyr 28 . The first set of residues lies within the N-terminal region containing the Cys 5 -Cys 9 disulfide, whereas the second group is found in the vicinity of the ␣-helix.…”

Section: Figmentioning

confidence: 98%

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The Solution Structure of the N-terminal Domain of Human Vitronectin

Mayasundari¹,

Whittemore²,

Serpersu

et al. 2004

Journal of Biological Chemistry

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The three-dimensional structure of an N-terminal fragment comprising the first 51 amino acids from human plasma vitronectin, the somatomedin B (SMB) domain, has been determined by two-dimensional NMR approaches. An average structure was calculated, representing the overall fold from a set of 20 minimized structures. The core residues (18 -41) overlay with a root mean square deviation of 2.29 ؎ 0.62 Å. The N-and Cterminal segments exhibit higher root mean square deviations, reflecting more flexibility in solution and/or fewer long-range NOEs for these regions. Residues 26 -30 form a unique single-turn ␣-helix, the locus where plasminogen activator inhibitor type-1 (PAI-1) is bound. This structure of this helix is highly homologous with that of a recombinant SMB domain solved in a co-crystal with PAI-1 (Zhou, A., Huntington, J. A., Pannu, N. S., Carrell, R. W., and Read, R. J. (2003) Nat. Struct. Biol. 10, 541-544), although the remainder of the structure differs. Significantly, the pattern of disulfide cross-links observed in this material isolated from human plasma is altogether different from the disulfides proposed for recombinant forms. The NMR structure reveals the relative orientation of binding sites for cell surface receptors, including an integrin-binding site at residues 45-47, which was disordered and did not diffract in the co-crystal, and a site for the urokinase receptor, which overlaps with the PAI-1-binding site.Human vitronectin is a glycoprotein found in the circulation, where it contributes to hemostasis by regulating blood coagulation and fibrinolysis (1, 2). Vitronectin is also found in the ECM, 1 where it plays important roles in cell adhesion, pericellular proteolysis, tissue invasion, angiogenesis, and metastasis (3-7). The variety of functions of vitronectin in the two microenvironments is a manifestation of its ability to interact with numerous humoral and cellular proteins. An important binding partner for vitronectin is the serine protease inhibitor PAI-1, which also is found both in circulation and the ECM. Furthermore, it has different activities depending upon this localization; the anti-protease activity of PAI-1 that regulates thrombolysis in the circulation is targeted instead toward pericellular proteolysis when localized to the ECM or cell/matrix boundary. Vitronectin binds to PAI-1 with high affinity and stabilizes the inhibitor in its active conformation (8, 9). Vitronectin can also associate with PAI-1 and assemble to form higher order complexes (10) that exhibit altered adhesive functions (11). Key to the adhesive functions of vitronectin are its interactions with cell-surface receptors including integrins and uPAR.A widely accepted model suggests that vitronectin is organized into functional domains that provide the broad repertoire necessary for binding to target ligands (12)(13)(14). We recently used computational methods to predict the structure of the three domains comprising vitronectin (15). A threading algorithm gave high confidence predictions for the central domai...

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Section: Figmentioning

confidence: 76%

Section: Methodsmentioning

confidence: 99%

Section: Figmentioning

confidence: 98%

See 1 more Smart Citation

The Solution Structure of the N-terminal Domain of Human Vitronectin

Mayasundari¹,

Whittemore²,

Serpersu

et al. 2004

Journal of Biological Chemistry

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show abstract

“…mm 3 and located at isocenter. Experimental parameters were as follows: TR; 2000 ms, TE; 50 ms, dummy scans; 4, averages; 4, acquisition duration; 512 ms, acquired vector size; 1024 points, bandwidth; 2000 Hz, RF offset frequency was set to water resonance frequency, and water suppression routine ''WET'' was turned off (27). The same voxel was shifted away from isocenter and RF offset frequency set to 1.70 ppm to evaluate off-resonance effects on slice profile.…”

Section: Phantom Slice Profilementioning

confidence: 99%

“…The ''WET'' water suppression method (27) was applied before the localization sequence. Spectral data was taken offline and concatenated, followed by further processing using Felix software package (http://www.felixnmr.com/).…”

Section: Human In Vivo Cosy Studiesmentioning

confidence: 99%

Adiabatic localized correlation spectroscopy (AL‐COSY): Application in muscle and brain

Ramadan

Mountford

2011

Magnetic Resonance Imaging

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Purpose: To describe an enhanced version of a localized correlation spectroscopy (L-COSY) by introducing adiabatic radiofrequency (RF) pulses for localization in two dimensions. Adiabatic pulses will improve slice selection profile and reduce chemical shift artifacts. Optimized Mao and adiabatic hyperbolic secant pulses are tested in vivo. Materials and Methods:Region of interest is localized by a 90 nonselective adiabatic RF pulse followed by two pairs of adiabatic RF pulses and a terminal 90 RF sinc pulse. Slice profiles for both refocusing pulses and chemical shift artifacts are measured in a water-oil phantom for L-COSY and AL-COSY. In vivo results of both COSY sequences are shown from muscle and brain on a 3 Tesla (T) scanner.Results: Chemical shift artifacts were reduced with AL-COSY compared with L-COSY. Slice profiles of adiabatic pulses were found to be sharper and more symmetrical than those of traditional Mao pulses. One-dimensional (1D) phantom studies showed longer T2 values using AL-COSY sequence. Comparison of 2D spectra obtained revealed spectroscopic peak volume improvements in AL-COSY and less residual water. In vivo 1D comparison showed more inphase and sharper peaks in AL-COSY spectrum. Conclusion:The AL-COSY sequence is an improved sequence due to sharper slice selection profiles, reduction of chemical shift artifacts, peak volume improvements in 2D techniques, and less J-modulation.

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Pulsed field gradients: a new tool for routine NMR

Parella

1998

Magn. Reson. Chem.

115

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A complete review of 1D and 2D gradient-based NMR experiments published since 1990 is provided. The ease of implementation and the excellent and reproducible results obtained from such experiments o †er a powerful tool for the study of molecular structures and dynamics. Thus, when sufficient sample concentration is available, ultra-clean spectra are obtained in very short acquisition times, making the experiments suitable for automated data acquisition. For these reasons, the concept of routine NMR work for chemists has been dramatically changed in the last few years and, with the correct choice of the experiments to be performed, a large number of chemical questions can be resolved in considerably reduced times. However, sensitivity and resolution are dependent on where the PFGs are incorporated into the pulse sequences and, therefore, these two important factors need to be considered in highly demanding applications. Illustrative examples of the most interesting applications to typical organic compounds are given.

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WET, a T1- and B1-Insensitive Water-Suppression Method for in Vivo Localized 1H NMR Spectroscopy

Cited by 676 publications

References 0 publications

The Solution Structure of the N-terminal Domain of Human Vitronectin

The Solution Structure of the N-terminal Domain of Human Vitronectin

Adiabatic localized correlation spectroscopy (AL‐COSY): Application in muscle and brain

Pulsed field gradients: a new tool for routine NMR

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