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Updated: May 3, 2026

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Published on: September 28, 2019
Alpha-synuclein lipid-dependent membrane binding and translocation through the α-hemolysin channel
Philip A Gurnev1, Thai Leong Yap2, Candace M Pfefferkorn2
1Physics Department, University of Massachusetts, Amherst, Massachusetts; Section on Molecular Transport, Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland.
Abstract:
Gauging the interactions of a natively unfolded Parkinson disease-related protein, alpha-synuclein (α-syn) with membranes and its pathways between and within cells is important for understanding its pathogenesis. Here, to address these questions, we use a robust β-barrel channel, α-hemolysin, reconstituted into planar lipid bilayers. Transient, ~95% blockage of the channel current by α-syn was observed when 1), α-syn was added from the membrane side where the shorter (stem) part of the channel is exposed; and 2), the applied potential was lower on the side of α-syn addition. While the on-rate of α-syn binding to the channel strongly increased with the applied field, the off-rate displayed a turnover behavior. Statistical analysis suggests that at voltages >50 mV, a significant fraction of the α-syn molecules bound to the channel undergoes subsequent translocation. The observed on-rate varied by >100 times depending on the bilayer lipid composition. Removal of the last 25 amino acids from the highly negatively charged C-terminal of α-syn resulted in a significant decrease in the binding rates. Taken together, these results demonstrate that β-barrel channels may serve as sensitive probes of α-syn interactions with membranes as well as model systems for studies of channel-assisted protein transport.
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