5LFJ

Crystal Structure of the Bacterial Proteasome Activator Bpa of Mycobacterium tuberculosis

Summary for 5LFJ

• Entry DOI: 10.2210/pdb5lfj/pdb
• Descriptor: Bacterial proteasome activator (2 entities in total)
• Functional Keywords: dodecamer, four-helix bundle, chaperone
• Biological source: Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)
• Total number of polymer chains: 4
• Total formula weight: 55515.20

Authors

Bolten, M.,Delley, C.L.,Leibundgut, M.,Boehringer, D.,Ban, N.,Weber-Ban, E. (deposition date: 2016-07-01, release date: 2016-11-23, Last modification date: 2024-01-10)

Primary citation

Bolten, M.,Delley, C.L.,Leibundgut, M.,Boehringer, D.,Ban, N.,Weber-Ban, E.
Structural Analysis of the Bacterial Proteasome Activator Bpa in Complex with the 20S Proteasome.
Structure, 24:2138-2151, 2016

PubMed Abstract: Mycobacterium tuberculosis harbors proteasomes that recruit substrates for degradation through an ubiquitin-like modification pathway. Recently, a non-ATPase activator termed Bpa (bacterial proteasome activator) was shown to support an alternate proteasomal degradation pathway. Here, we present the cryo-electron microscopy (cryo-EM) structure of Bpa in complex with the 20S core particle (CP). For docking into the cryo-EM density, we solved the X-ray structure of Bpa, showing that it forms tight four-helix bundles arranged into a 12-membered ring with a 40 Å wide central pore and the C-terminal helix of each protomer protruding from the ring. The Bpa model was fitted into the cryo-EM map of the Bpa-CP complex, revealing its architecture and striking symmetry mismatch. The Bpa-CP interface was resolved to 3.5 Å, showing the interactions between the C-terminal GQYL motif of Bpa and the proteasome α-rings. This docking mode is related to the one observed for eukaryotic activators with features specific to the bacterial complex.

PubMed: 27839949
DOI: 10.1016/j.str.2016.10.008

Experimental method

X-RAY DIFFRACTION (2.6 Å)