Single-molecule nanopore dielectrophoretic trapping of α-Synuclein with lipid membranes

ABSTRACT The lipid-α-Synuclein (α-Syn) interaction plays a crucial role in the pathogenesis of Parkinson’s disease. Here, we trap α-Syn at a conjunction of an α-hemolysin (αHL) single nanopore-lipid to investigate the folding and unfolding kinetics of α-Syn in a lipidic environment. The hybridized α-Syn is generated through a reaction between a 5’-thiol-modified nucleotide oligo (dC30) and the α-Syn mutant (A140C). Owing to an applied voltage, single-molecule hybridized α-Syn can be trapped at the single nanopore. The trapping events are associated with dielectrophoretic force. The folding and unfolding events of α-Syn can be observed at the pore-membrane junction through interpretation of blockade current amplitudes and dwell time. This can be related to the protein quaternary structure influenced by the α-Syn-membrane interaction, allowing further analysis of α-Syn conformational dynamics. We studied how disease associated metal ions (Cu 2+ , Zn 2+ ) modulate folding and unfolding of α-Syn at the interface of the membranes and pore, and how α-helical peptidomimetics stabilize the helical conformation of α-Syn in the presence of a membrane. These studies aid our understanding of the complexity of the interaction of α-Syn, lipid membranes and metal ions, and in using peptidomimetics, a new strategy against α-Syn toxicity and aggregation is advanced.