Fig. 2. (A) 2D IR spectrum of the L12A13 hIAPP in 100 mM SDS micelle solution. Unlabeled amides give rise to a broad band at 1650 cm^–1 (peak A). A strong signal from the isotope labels is clearly seen at 1603 cm^–1 (peak B). (B) Diagonal slices through the ν = 1–2 band for all the studied isotope labels measured in SDS micelles. Only the L12A13 label (peak B) shows a strong positive coupling and a great intensity enhancement with respect to the corresponding single label (C) The sequence and NMR structure of human amylin in SDS micelles with the isotope labeling sites highlighted.