1H-NMR Studies of Copper Binding by Histidine Containing Peptides

We review recent developments in the studies of Cu(II) complexes with histidine-containing peptides in solution by NMR. An overview of the theoretical background of the effects of the paramagnetic metal on the NMR properties (relaxation and shift) of nearby nuclei is given. Particular attention is paid to the effect of exchange rates between free and metal-bound forms of the ligand on detection of paramagnetic relaxation rates. General methods are underlined to determine the structure of the complexes (and thus the donor set to the metal) and to distinguish between the binding of copper(II) to either N-1 or N-3 of the imidazole ring of histidine. Examples are reported dealing with fragments of the amyloid precursor protein (a protein related to Alzheimer's disease) and of the prion protein (related to Creutzfeldt–Jakob disease) in which the binding of copper may be relevant for subsequent redox activities, protein aggregation or metal-catalyzed protein damage.