Fig. 5: Single-particle cryo-EM structure of PA26-αWTββαK66A complex without substrate.
From: Allosteric coupling between α-rings of the 20S proteasome
a Cryo-EM reconstruction of PA26-αWTββαK66A at a resolution of 3.5 Å. b, e Proximal and distal α-ring of the 20S CP. c, f Ribbon diagram of α-subunits from proximal and distal α-rings. Note that the N-terminus of proximal α-subunit points upwards, consistent with an open gate conformation. In contrast, the N-terminus of distal α-subunit points downwards, consistent with a closed gate conformation. d Ribbon diagram of an α-subunit from the proximal α-ring and its interacting β-subunit (gray) overlayed with the ribbon diagram of α/β-subunits from a 20S CP without activator bound (purple). Note that both α- and β-subunits are well-aligned between the two. g Kinetics of LFP degradation by symmetric (blue) and asymmetric (yellow) 20S CP alone and with double (black) and single (red) activator PA26. Three (n = 3) biologically independent experiments were carried out to derive the mean and standard deviation. The means are used to derive the curve and the error bars represent standard deviation.
