IMPROVED RESOLUTION IN TRIPLE-RESONANCE SPECTRA BY NONLINEAR SAMPLINGIN THE CONSTANT-TIME DOMAIN

Nonlinear sampling along the constant-time dimension is applied to the constant-time HNCO spectrum of the dimerization domain of Gal4. Nonli near sampling was used for the nitrogen dimension, while the carbon an d proton dimensions were sampled linearly. A conventional ct-HNCO spec trum is compared with a nonlinearly sampled spectrum, where the gain i n experiment time obtained from nonlinear sampling is used to increase the resolution in the carbonyl dimension. Nonlinearly sampled data ar e processed by maximum entropy reconstruction. It is shown that the no nlinearly sampled spectrum has a higher resolution, although it was re corded in less time. The constant intensity of the signal in the const ant-time dimension allows for a variety of sampling schedules. A sched ule of randomly distributed sampling points yields the best results. T his general method can be used to significantly increase the quality o f heteronuclear constant-time spectra.