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

The lipid--Synuclein (-Syn) interaction plays a crucial role in the pathogenesis of Parkinsons disease. Here, we trap -Syn at a conjunction of an -hemolysin (HL) single nanopore-lipid to investigate the folding and unfolding kinetics of -Syn in a lipidic environment. The hybridized -Syn is generated through a reaction between a 5-thiol-modified nucleotide oligo (dC30) and the -Syn mutant (A140C). Owing to an applied voltage, single-molecule hybridized -Syn can be trapped at the single nanopore. The trapping events are associated with dielectrophoretic force. The folding and unfolding events of -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 -Syn-membrane interaction, allowing further analysis of -Syn conformational dynamics. We studied how disease associated metal ions (Cu2+, Zn2+) modulate folding and unfolding of -Syn at the interface of the membranes and pore, and how -helical peptidomimetics stabilize the helical conformation of -Syn in the presence of a membrane. These studies aid our understanding of the complexity of the interaction of -Syn, lipid membranes and metal ions, and in using peptidomimetics, a new strategy against -Syn toxicity and aggregation is advanced.