Fig. 1: N-terminal acetylation of α-synuclein enhances overall membrane binding and sensitivity for lipid packing defects.

A Structures of WT- and NTA-αSyn (modified from UniProt P61144). B Schematic of the tethered vesicle assay (left) with a representative DLS/fluorescence intensity calibration plot for fluorescent SUVs (middle) and a representative single-molecule fluorescence intensity distribution for fluorescent αSyn (right). Scale bar represents 2 µM. C Lipid, protein, and merged fluorescence micrographs of tethered SUVs in the presence of 1 µM αSyn. Scale bars represent 2 µm. Yellow boxes highlight representative SUVs with bound αSyn and the corresponding three-dimensional intensity profiles in the αSyn fluorescence channels. D (top) The distribution of diameters for analyzed vesicles that were incubated with 1 µM αSyn and (bottom) the number of proteins bound to the individual SUVs from the top panel. E NTA-αSyn preferentially binds to neutral, defect-rich DPhPC membranes over anionic DOPC/DOPS membranes. DOPC/DOPS membranes contained a 3:1 (mol:mol) DOPC:DOPS. This schematic is a qualitative representation of αSyn-membrane association and is not intended to quantitatively reflect αSyn size and penetration depth relative to the membrane surface. The black dashed lines in (D) indicate the average values of the distributions. n.s. not significant as determined by unpaired Student’s t-test. *** correspond to P < 0.001 as determined by Welch’s t-test (WT) and unpaired Student’s t-test (NTA). The schematics in panels B and E are the original creations of the authors and were not generated or obtained from external sources.