alpha-Synuclein is a protein abundant in presynaptic terminals in the brain. The N-terminal region of the sequence contains an imperfect 11-residue periodicity also found in A-class apolipo-proteins and able to fold into an amphipathic helix. Here, the ability of three fragments of the protein, which include one, two, and all repeats, respectively, to bind to vesicles of different phospholipid composition is described. The results suggest a cooperative action of the repeals in selecting tat-get membranes for interaction based on their lipid composition. This deduction is possibly related to the physiological role of the protein, which is still poorly understood.