Figure 3

From: Evidence for Intramolecular Antiparallel Beta-Sheet Structure in Alpha-Synuclein Fibrils from a Combination of Two-Dimensional Infrared Spectroscopy and Atomic Force Microscopy

Figure 3

(A) 2D-IR spectrum, with (on top) the 1D-IR spectrum and (on the right side) the diagonal slice of the fibril formed by the hexapeptide VEALYL, that has an antiparallel orientation of β-strand monomers along the fibril axis, showing a canonical antiparallel β-sheet peak pattern with a perpendicular orientation of the low- with respect to the high-frequency modes, and (B) the slice at νpump = 1620 cm−1. The cross peak at (νprobe, νpump) = (1680, 1620) cm−1 with an anisotropy R = −0.21 ± 0.03 reveals that there is a 90 ± 11° angle between the modes that the low- and the high-frequency peaks are composed of.