School of Medicine
Protein degradation in all domains of life requires ATPases that unfold and inject proteins into compartmentalized proteolytic chambers. Proteasomal ATPases in eukaryotes and archaea contain poorly understood N-terminally conserved coiled-coil domains. In this study, we engineer disulfide crosslinks in the coiled-coils of the archaeal proteasomal ATPase (PAN) and report that its three identical coiled-coil domains can adopt three different conforma- tions: (1) in-register and zipped, (2) in-register and partially unzipped, and (3) out-of-register. This conformational heterogeneity conflicts with PAN’s symmetrical OB-coiled-coil crystal structure but resembles the conformational heterogeneity of the 26S proteasomal ATPases’ coiled-coils. Furthermore, we find that one coiled-coil can be conformationally constrained even while unfolding substrates, and conformational changes in two of the coiled-coils reg- ulate PAN switching between resting and active states. This switching functionally mimics similar states proposed for the 26S proteasome from cryo-EM. These findings thus build a mechanistic framework to understand regulation of proteasome activity.
Digital Commons Citation
Snoberger, Aaron; Brettrager, Evan J.; and Smith, David M., "Conformational switching in the coiled-coil domains of a proteasomal ATPase regulates substrate processing" (2018). Faculty & Staff Scholarship. 1530.
Snoberger, A., Brettrager, E. J., & Smith, D. M. (2018). Conformational switching in the coiled-coil domains of a proteasomal ATPase regulates substrate processing. Nature Communications, 9(1). https://doi.org/10.1038/s41467-018-04731-6