Figure 2.

Examples of spectral quality used for deriving ¹D_CβCγ couplings. (A) Small section of the methyl region of the ¹H–¹³C HSQC spectrum of wild-type GB3 in Pf1 medium, recorded with regular (non-CT) ¹³C evolution (red), superimposed on the corresponding spectrum recorded under isotropic conditions (blue). (B) Small region of the ¹H^β–¹³C^β region of the ¹H–¹³C CT-HSQC spectrum, recorded with a REBURP 180° pulse covering only the ¹³C aliphatic region during the CT ¹³C evolution of the aliphatic region of wild-type GB3 in Pf1 medium (red) superimposed on the corresponding spectrum recorded under isotropic conditions (blue). The spectra were recorded with a double constant-time duration (56 ms) at 900 MHz. (C) Comparison of ¹D_CαCβ and the sum of the three other C^β–related ¹D couplings, which all have been scaled to ¹D^a_CH (measurements for wild type GB3: pink, in bicelle; blue, in PEG; green, in Pf1).