Interaction of Cu(II) and Ni(II) with Ypk9 Protein Fragment via NMR Studies

Figure 10

3D structural model, derived from NMR structural constraints (ROEs), for the Ni(II) ion complexed with PK9-H peptide in a pentacoordinated geometry, with the involvement of the N𝛿₁ imidazole nitrogen of the histidine residue, three deprotonated amidic nitrogens from the peptide backbone (belonging to His-5, Lys-4, and Glu-3 residues), and the carboxylate moiety from aspartyl (Asp-2) residue in the apical position, giving a {N_Im,3N⁻,O⁻} species.