Figure 2.

Intensity ratios I_ox/I_red for each spin-label position for (A) αS,^12,17 (B) βS, and (C) βS_HC. The experimental data are shown as black bars, and the I_ox/I_red values calculated from the random coil ensemble are plotted as thick red lines. PRE–NMR experiments were conducted on 100 μM uniformly ¹⁵N-labeled protein with MTSL attached in 10 mM sodium phosphate (pH 7.4), 100 mM NaCl, and 10% D₂O at 10 °C. The experimental I_ox/I_red values are those processed for use in the simulations (see Methods); thus, any I_ox/I_red of <0.15 or >0.85 has been set to 0.15 or 0.85, respectively. If no bar is present, then either I_ox/I_red was not measured for this residue or it was discarded because of an uncertainty of >10%.