Fig. 5: Valency tunes the sequence preferences of h20S PAs.
From: The YΦ motif defines the structure-activity relationships of human 20S proteasome activators
a Proteasome activity of heptameric PA26E102A-Opt5 (YY, circle) and C-terminally modified variants, YP2F mutant (YF, square) and YP3F mutant (FY, triangle). b Similar to a except using C-terminally modified mutants of MBP, tested alongside wildtype MBP (wt, ‘x’). Data are normalized to YY and plotted individually (n = 3 or 4). Reported EC50 is a mean of EC50 values calculated from three independent experiments (n = 3 or 4) with error reported as s.e.m. c Proteasome stimulation by monovalent Opt5 peptides (gray), monovalent MBPOpt5 chimeras (orange), and multivalent PA26E102A-Opt5 (blue). YΦ is a composite of YY and YF activators. Data are calculated from three independent experiments (see Supplementary Fig. 4g, h), normalized to YY, and plotted individually (open circles, n = 6 or 3) with error reported as s.e.m. P-values were calculated using unpaired t-test: *p < 0.05, **p < 0.01, and ***p < 0.001.
