Figure 1: Effect of Oprozomib.
(a) SDS–PAGE of purified human proteasomes. (b) Surface view of the human Oprozomib-bound 26S proteasome cryo-EM density map at 3.8 Å resolution. The CP (20S) subcomplex is depicted in grey, the AAA+ ATPase subcomplex in green and the remaining RP (19S) components in yellow. (c) Local resolution map of the structure shown in b Each part of the density is coloured according to the local resolution as specified in the colour bar. The resolution ranges from 3.5 Å (blue) to 6 Å (red). (d) Atomic model of the complete 26S proteasome. The model is coloured according to the B-factor distribution. B factors range from 25 Å2 (blue) to 175 Å2 (red). (e) Close-up view of the Oprozomib binding site in the β5 subunit of the CP. The Oprozomib model is coloured in red the CP subunits are shown in brown. (f) Close-up view of the empty Oprozomib binding site in the β5 subunit of the CP. The Oprozomib model is coloured in red the CP subunits are shown in brown. (g) Schematic representation of the two major rotational modes of the RP reveals a rotation of the RP along the long axis of the 26S proteasome as indicated in a cartoon representation as a visual aid. (h) Histogram of the relative distribution of 26S proteasome particles found in either the rotated or the non-rotated state which can be modified by epoxyketone inhibitor binding. The control dataset (DMSO) reveals an almost balanced distribution with ∼41% of the particles in the rotated state. The number of particles in the rotated state is significantly reduced upon Oprozomib (∼13% rotated) or Epoxomicin (∼25% rotated) binding. Error bars displaying s.d. indicate a high reproducibility based on data from three independent proteasome preparations (n=3).
