Capreomycin is an important therapeutic agent having intriguing and diverse molecular features. Its polypeptidic structure rich in nitrogen donors makes the drug a promising chelating agent for a number of transition metal ions, especially for copper(II). The results of the model investigational studies suggest that capreomycin anchors Cu(2+) ion with an amino function of the α,β-diaminopropionic acid residue at pH around 5. At physiological pH copper(II) ion is coordinated by two deprotonated amide nitrogen atoms of the α,β-diaminopropionic acid, the serine residue as well as the amino function deriving from the β-lysine. Above that pH value we observe a rearrangement within the coordination sphere leading to movement of Cu(2+) to the center of the peptide ring with concurrent coordination of four nitrogen donors. Spin-lattice relaxation enhancements and potentiometric measurements clearly indicate that deprotonated amide nitrogen atom from the β-ureidodehydroalanine moiety is the fourth donor atom.