Growing evidence supports a link between brain copper homeostasis; the formation of alpha-synuclein (AS)-copper complexes, and the development of Parkinson disease (PD). Recently it was demonstrated that the physiological form of AS is N-terminally acetylated (AcAS). Here we used NMR spectroscopy to structurally characterize the interaction between Cu(I) and AcAS. We found that the formation of an AcAS Cu(I) complex at the N-terminal region stabilizes local conformations with alpha-helical secondary structure and restricted motility. Our work provides new evidence into the metallo-biology of PD and opens new lines of research as the formation of AcAS Cu(I) complex might impact on AcAS Membrane binding and aggregation.