Extended Data Fig. 7: Continued cryo-EM data processing for the 30 s data set, focusing on Rpn1 classification.
From: NUB1 traps unfolded FAT10 for ubiquitin-independent degradation by the 26S proteasome
a) Using Rpn1-masked classification and refinement, 10 models of the non-processing hs26S proteasome are shown with particle numbers. Models 1 and 6 (left) show a blurry Rpn1 with continuous density, while the other 8 exhibit a resolved Rpn1 yet in slightly varied positions. b) An alignment of all Rpn1-resolved classes highlights these subtle differences in Rpn1 and therefore NUB1’s UBL position. The highest resolution class of the 19S RP subcomplex was further refined and used to build an atomic model (bottom left), for which the Gold-Standard FSC plot, map-to-model FSC plot, and distribution of particle orientations are show. Since NUB1’s UBL domain was at slightly lower resolution, further local refinement was performed on the Rpn1-NUB1 UBL interaction with all 8 Rpn1-resolved classes (bottom right), also showing the Gold-Standard FSC plot, map-to-model FSC plot, and distribution of particle orientations.
