NMR chemical shift differences for Mut1, Mut1-S12, and Mut1-S23 relative to unfolded controls (Mut1-S1, Mut1-S2, and Mut1-S3). Downfield shifting of > 0.1 ppm indicate beta-sheet structure. Upfield shifting of Asn9 and Asn19 is consistent with a beta-turn conformation. Upfield shifting of K24 is due to ring current effects from the cross-strand Trp15. Conditions: 25 °C, 50 mM potassium dideuterium phosphate, pD 7.4 (uncorrected), referenced to DSS. Error is ± 0.01 ppm, as determined by the acquired points and spectral width.