Interaction of α-Synuclein and a Cell Penetrating Fusion Peptide with Higher Eukaryotic Cell Membranes Assessed by <sup>19</sup>F NMR

2016-02-21T16:10:17Z (GMT) by Imola G. Zigoneanu Gary J. Pielak
We show that fluorine NMR can be used to monitor the insertion and change in conformation of a <sup>19</sup>F-labeled cell-penetrating peptide upon interacting with the cellular plasma membrane. α-Synuclein and a construct comprising a cell-penetrating peptide covalently attached to its N-terminus were studied. Important information about the interaction of the proteins with CHO-K1 cells was obtained by monitoring the diminution of <sup>19</sup>F resonances of 3-fluoro-l-tyrosine labeled proteins. For α-synuclein, a decrease in the resonance from position 39 was observed indicating that only the N-terminal third region of the protein interacts with plasma membrane. However, when the fusion construct was incubated with the cells, a decrease in the resonance from the fusion peptide region was noted with no change in the resonances from α-synuclein region. Longer incubation, studied by using confocal fluorescence microscopy, revealed that the fusion construct translocates into the cells, but α-synuclein alone did not cross the membrane in significant amounts.