The amino acid residues in Ab affected upon interaction with 7 were further investigated by two-dimensional band selective optimized flip-angle short transient-heteronuclear multiple quantum correlation nuclear magnetic resonance (2D SOFAST-HMQC NMR) spectroscopy employing both N-labeled Ab42 and Ab40. As presented in Fig. and, the chemical shift perturbations (CSPs) provoked by adding 7 to uniformly 15 N-labeled Ab42 were detected. The Gln15, Phe19, Gly33, and Leu34 residues in Ab42 were changed by treatment of 7, which implies that the compound could affect the amino acid residues adjacent to the b-turn motif (Val12-Gln15), self-recognition site (Leu17-Ala21), and C-terminal region (Ile32-Ala42) of Ab42 that are highly linked to its fibrilization. Therefore, this interaction between 7 and Ab42 could cause a change in the conformation and aggregation propensity of Ab42. Moreover, the overall peak intensity of N-labeled Ab42 was decreased by ca. 20% upon addition of 7, suggesting the production of NMR-invisible Ab aggregates. In the case of Ab40, 2D SOFAST-HMQC NMR spectra obtained from N-labeled Ab40 with and without 7 manifested the compound's plausible interactions with Glu3, Glu11, Phe20, and Leu34 with the reduced overall peak intensity (ca. 10%), as depicted Fig. and. In a similar manner to Ab42, 7 could alter the aggregation of Ab40 by interacting with the regions close to the b-turn motif (Val12-Gln15) and the self-recognition (Leu17-Ala21)