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MQD--multiplex-quadrature detection in multi-dimensional NMR.

Schlagnitweit J, Horničáková M, Zuckerstätter G, Müller N - Chemphyschem (2011)

Bottom Line: Thus the number of acquisitions required to achieve a desired resolution in the indirect dimensions is significantly reduced.The minimum number of transients per indirect data point, which have to be combined to give pure-phase spectra, is thus decreased by a factor (3/4)(N-1).This reduction is achieved without adjustable parameters.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria.

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2D slices of the States-TPPI (left) and MQD (right) HNCO experiments of the protein PsbQ (including assignment of peaks; n.a. means that this peak could not be assigned).26b The 3D spectra were obtained in the same amount of time by acquiring a different number of data points in the indirect dimensions (TD1=54 and TD2=96 using the standard sequence and TD1=TD2=96 using MQD,). The MQD raw data were pre-processed as described in the Experimental Section. Then the 3D data sets were processed in TopSpin 2.1. Zero-filling in both indirect dimensions to 256 data points and squared-cosine-window functions were used.
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fig04: 2D slices of the States-TPPI (left) and MQD (right) HNCO experiments of the protein PsbQ (including assignment of peaks; n.a. means that this peak could not be assigned).26b The 3D spectra were obtained in the same amount of time by acquiring a different number of data points in the indirect dimensions (TD1=54 and TD2=96 using the standard sequence and TD1=TD2=96 using MQD,). The MQD raw data were pre-processed as described in the Experimental Section. Then the 3D data sets were processed in TopSpin 2.1. Zero-filling in both indirect dimensions to 256 data points and squared-cosine-window functions were used.

Mentions: Instead of shortening experiments at unchanged resolutions one can take the advantage of the saved time to achieve resolution enhancement. Therefore, we compare results of an MQD to a States-TPPI HNCO experiment obtained in the same amount of time. In the standard experiment 27 complex points were acquired in the carbon dimension, while in the MQD experiment 48 complex points could be recorded in the same time. In Figure 4 we show a representative region of the proton–nitrogen plane at the 13CO chemical shift (179.9 ppm) of residue L104. An intense cross-peak connects this C to the 1H15N pair of Q105. Six cross-peaks, four of them with similarly high amplitudes, appear in the States-TPPI HNCO due to similar CO shifts. Only the four bigger peaks appear in the same plane of the MQD HNCO experiment, and significant amplitude differences reduce assignment ambiguities substantially. This comparison corroborates the advantage of using the time saved by the multiplex approach to accommodate more evolution-time increments, thereby increasing the resolution in the indirect dimensions.


MQD--multiplex-quadrature detection in multi-dimensional NMR.

Schlagnitweit J, Horničáková M, Zuckerstätter G, Müller N - Chemphyschem (2011)

2D slices of the States-TPPI (left) and MQD (right) HNCO experiments of the protein PsbQ (including assignment of peaks; n.a. means that this peak could not be assigned).26b The 3D spectra were obtained in the same amount of time by acquiring a different number of data points in the indirect dimensions (TD1=54 and TD2=96 using the standard sequence and TD1=TD2=96 using MQD,). The MQD raw data were pre-processed as described in the Experimental Section. Then the 3D data sets were processed in TopSpin 2.1. Zero-filling in both indirect dimensions to 256 data points and squared-cosine-window functions were used.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3298640&req=5

fig04: 2D slices of the States-TPPI (left) and MQD (right) HNCO experiments of the protein PsbQ (including assignment of peaks; n.a. means that this peak could not be assigned).26b The 3D spectra were obtained in the same amount of time by acquiring a different number of data points in the indirect dimensions (TD1=54 and TD2=96 using the standard sequence and TD1=TD2=96 using MQD,). The MQD raw data were pre-processed as described in the Experimental Section. Then the 3D data sets were processed in TopSpin 2.1. Zero-filling in both indirect dimensions to 256 data points and squared-cosine-window functions were used.
Mentions: Instead of shortening experiments at unchanged resolutions one can take the advantage of the saved time to achieve resolution enhancement. Therefore, we compare results of an MQD to a States-TPPI HNCO experiment obtained in the same amount of time. In the standard experiment 27 complex points were acquired in the carbon dimension, while in the MQD experiment 48 complex points could be recorded in the same time. In Figure 4 we show a representative region of the proton–nitrogen plane at the 13CO chemical shift (179.9 ppm) of residue L104. An intense cross-peak connects this C to the 1H15N pair of Q105. Six cross-peaks, four of them with similarly high amplitudes, appear in the States-TPPI HNCO due to similar CO shifts. Only the four bigger peaks appear in the same plane of the MQD HNCO experiment, and significant amplitude differences reduce assignment ambiguities substantially. This comparison corroborates the advantage of using the time saved by the multiplex approach to accommodate more evolution-time increments, thereby increasing the resolution in the indirect dimensions.

Bottom Line: Thus the number of acquisitions required to achieve a desired resolution in the indirect dimensions is significantly reduced.The minimum number of transients per indirect data point, which have to be combined to give pure-phase spectra, is thus decreased by a factor (3/4)(N-1).This reduction is achieved without adjustable parameters.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria.

Show MeSH
Related in: MedlinePlus