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The 2D w1,w2-X-edited (filtered or selected) NOESY experiment affords a 2D NOESY spectrum in which 1H directly-attached to a X nuclei are efficiently filtered or selected before and after evolution during the t1 and the acquisition periods. This experiment is widely used to study protein-ligand complexes, where the protein is usually 13C and/or 15N-labeled and the ligand is at natural abundance .REQUIREMENTS
Easy implementation on any AVANCE spectrometer equipped with an inverse probehead.VERSIONS
The basic sequence of the 2D w1,w2-X-edited NOESY experiment is easily designed by replacing the initial and final 90º 1H pulses of a conventional 2D NOESY pulse scheme by X half-filters:EXPERIMENTAL DETAILS
The 2D w1,w2-X-edited NOESY experiment can be recorded in routine/automation modes. The experiment is basically optimized as described for the 2D NOESY experiment. The X half-filters are optimized as described in a regular HMQC experiment and the phase cycle is selected in order to select or to filter the desired isotope.SPECTRA
The 2D w1,w2-X-edited NOESY spectrum shows a typical 2D NOESY map in which cross-peaks show E.COSY pattern. The nJ(CH) values are measured from signal displacement in two F1 slices through each signal of the cross-peak doublet split by 1J(CH) in the F1 dimension. Thus, coupling constants smaller than the linewidth can be determined accurately. In addition, the pulse sequence contains no delays to evolve nJ(CH) as in HMBC-like experiments, which simultaneous allows evolution of J(HH). Therefore, the spectrum is free from J(HH) modulation and it can be phased to pure absorption.RELATED TOPICS
Other closely related experiments are:
- 2D Inverse experiments
- 2D Inverse gradient-enhanced experiments
- 2D w1-X-edited NOESY experiment.
- 2D w2-X-edited NOESY experiment.
- 3D HMQC-NOESY-HMQC experiment
- 4D HMQC-NOESY-HMQC experiment
