S1. For the selective pulse it is also important that it does not produce excitation sidebands and gives little phase distortions across the excitation region.
We obtained best results using an E-BURP2 shaped pulse [22] for excitation. As a compromise between selectivity and sensitivity we employed a 40 ms pulse. The selective 180° pulse used in the excitation sculpting blocks is less demanding as far as the excitation profile is concerned and we typically used a 4 ms square pulse. The longer this “purging” pulse is the sharper the region around the diagonal INCB28060 nmr which is suppressed. However, this pulse cannot be made too selective due to diffusion between the excitation and the diagonal suppression.
Diagonal peaks which Galunisertib are excited at the beginning in a very narrow slice then start to diffuse during the pulse sequence and it is important that the pulse used during the excitation sculpting block acts on all spins that were excited in a slice, including the ones that changed their location by diffusion. Therefore, the width of the suppressed diagonal can be made narrower for larger, more slowly diffusing molecules. In the case of negligible diffusion during the pulse-sequence (proteins and other large molecules) the bandwidth of the selective pulse used to suppress the diagonal peaks can be as narrow as the original excitation pulse. However, the purging pulse must not be more selective than the excitation pulse since this would lead to cancellation of diagonal peaks in slices narrower than the excitation slices and therefore reintroduce diagonal peaks from nearby sample tube regions. One nice feature, Liothyronine Sodium inherent to slice-selective excitation, is its insensitivity to poor shimming (magnetic field inhomogeneities) along the z-direction
[23]. Therefore, the signals obtained in our diagonal-suppressed spectra are characterized by very narrow line-widths, even if the magnetic field is not very homogenous. NOESY spectra of lysozyme were recorded on a Bruker AVANCE III 700 MHz NMR spectrometer using a 5 mm TCI cryo probe at 298 K. All other spectra were acquired on a Bruker AVANCE III 500 MHz spectrometer using a 5 mm TCI probe at 298 K. For all 2D experiments data matrices of 1024 × 128 complex data points were acquired and, after zero filling to twice the number of points, multiplied by a 60° phase-shifted squared sine-bell window function in both dimensions. The highly derivatized sugar methyl-4,6-O-benzylidene-2,3-O-ditosyl-α-glucopyranoside was obtained from Prof. Karl Dax at the Graz University of Technology. All other compounds were from Sigma Aldrich (St. Louis, USA) in the highest purity available.