Biomolecular Complexes

Biological function is triggered by protein-ligand interactions. As several NMR parameters change upon binding, a number of NMR approaches have been developed to investigate interacting biomolecules. Changes in the chemical shifts can be observed. The signs and intensities of NOE signals are an important source of information. The diffusion constants of the bound vs. free ligand differ and the line widths are altered due to differences in the relaxation properties of the ligand. 
 
Binding sites on both the ¹⁵N,¹³C-labeled protein and the unlabeled ligand can be mapped by using so called X-filtered experiments. The setup of these experiments that monitor the NOE interactions between the two interacting components, becomes straight forward when using appropriate software tools.
 

more on experimental setup by using TopSpin/ Biotools