Figure 6.

Effects of molecular rotational motion on distance measurements on the 23L/131R1p mutant. Three different conditions were investigated, namely protein in buffer at 298 K, protein in buffer with 30% (w/v) sucrose (298 K), and protein immobilized on the CNBr-sepharose (298 K, see row labels). For each row, two theories, the fast motional approximation (the “Fast” column) and the rigid motional approximation (the “Rigid” column), were used to calculate the average Cu²⁺-R1p distances based on SR data (green bars) and the “DEER-averaged” distance (red bars). Black curves are the Cu²⁺-nitroxide distance distribution measured from DEER on 23L/131R1p with 25% (v/v) glycerol as a cryoprotectant.