Fig. 4: P3 and P2 residues make intramolecular π-stacking interactions within the h20S α-pockets.
From: The YΦ motif defines the structure-activity relationships of human 20S proteasome activators
a Experimental and theoretical distances (R) and angles of incidence (θ) for adjacent P2 and P3 tyrosine residues37. Values are of bound Opt5 from the cryo-EM structure (n = 6) and reported as mean ± s.d. See Supplementary Table 3 for individual measurements. b Structure of the side chains from unnatural amino acids used in this study. c P2 modifications to the π electron density decreases the stimulatory effect of Opt5. Data are normalized to Opt5YF and plotted individually (n = 2 to 4). Reported EC50 is a mean of EC50 values calculated from two to four independent experiments with error reported as s.e.m.
