Chemical-shift mapping

A comparably simple approach uses perturbations of the target s chemical shifts to confirm binding. Multidimensional spectra are usually used, as signal overlap obscures the analysis in ID spectra. In these spectra, the displacement of peaks due to the binding event is monitored. Obviously, the use of 2D- or 3D spectra results in an increased experimental time. As an additional feature of this technique, the dissociation constant may be extracted from the experiment. This analysis is possible if the displacement is related to the concentration of the ligand via a titration. Of course, these experiments require a reference spectrum without the ligand. 

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Fig. 2 Chemical shift perturbation and chemical shift mapping, (a) Portions of the [15N, 1H]-HSQC spectra of Bcf-xL recorded in absence (black) and in presence of each of the four molecules (in colors). Resonance assignments for amino acid residues that exhibit large shifts are reported, (b) Structure of Bc1-Xl in complex with the BH3 peptide from Bak (PDB code 1BXL) showing the chemical shift changes in Bcl-xL upon ligand binding (blue, large shits yellow, no shifts the Bak peptide is reported in cyan). Adapted from [48]...

Fig.2 The calculated 13C chemical shift map of the Cp carbon in N-acetyl-N -methyl-L-alanine amide obtaining using the FPT INDO method. The chemical shifts were calculated at 15° intervals for the dihedral angles(< >,i /).

Figure 8.2.9 CSI experiment using four samples stacked vertically. The resulting contour plot is a spatial/chemical-shift map, which can be analysed by taking slices along the frequency axis to yield individual spectra for each sample position. Reprinted with permission from Hou, T., Smith, J., MacNamara, E., Macnaughtan, M. and Raftery, D., Anal. Chem., 73, 2541-2546 (2001). Copyright (2001) American Chemical Society...

P Sheet environments using an empirical chemical shift map. 

Chemical shift maps for 1-substituted pentanes were worked out by Barfield," who could analyse various substitution effects in dependence on the molecular conformation. Of special interest was the origin of the - and -elfect. 

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