Remaining structures at the N- and C-terminal regions of alpha-synuclein accurately elucidated by amide-proton exchange NMR with fitting

Alpha-synuclein is analyzed in physiological conditions by CLEANEX-PM methodology, in which the amide-proton exchange can be monitored at millisecond scale. The relationship between kex and [OH]− is confirmed as a linear correlation with slope 1, indicating EX2 regime. There are significant residual structures at the N- and C-terminal regions. The structure at the C-terminal region is more stable than that of the N-terminal region. The middle part including NAC region is not completely protected. The data acquired at various pH and mixing time conditions followed by linear fitting give accurate information about residual structures.