5Y9N

Crystal structure of Pyrococcus furiosus PbaA (monoclinic form), an archaeal homolog of proteasome-assembly chaperone

Summary for 5Y9N

• Entry DOI: 10.2210/pdb5y9n/pdb
• Related: 3WZ2
• Descriptor: PbaA, CHLORIDE ION (3 entities in total)
• Functional Keywords: proteasome, proteasome activator, proteasome assembly chaperone, chaperone
• Biological source: Pyrococcus furiosus (strain ATCC 43587 / DSM 3638 / JCM 8422 / Vc1)
• Total number of polymer chains: 10
• Total formula weight: 274202.79

Authors

Yagi-Utsumi, M.,Sikdar, A.,Kozai, T.,Inoue, R.,Sugiyama, M.,Uchihashi, T.,Satoh, T.,Kato, K. (deposition date: 2017-08-26, release date: 2018-01-17, Last modification date: 2023-11-22)

Primary citation

Yagi-Utsumi, M.,Sikdar, A.,Kozai, T.,Inoue, R.,Sugiyama, M.,Uchihashi, T.,Yagi, H.,Satoh, T.,Kato, K.
Conversion of functionally undefined homopentameric protein PbaA into a proteasome activator by mutational modification of its C-terminal segment conformation
Protein Eng. Des. Sel., 31:29-36, 2018

PubMed Abstract: Recent bioinformatic analyses identified proteasome assembly chaperone-like proteins, PbaA and PbaB, in archaea. PbaB forms a homotetramer and functions as a proteasome activator, whereas PbaA does not interact with the proteasome despite the presence of an apparent C-terminal proteasome activation motif. We revealed that PbaA forms a homopentamer predominantly in the closed conformation with its C-terminal segments packed against the core domains, in contrast to the PbaB homotetramer with projecting C-terminal segments. This prompted us to create a novel proteasome activator based on a well-characterized structural framework. We constructed a panel of chimeric proteins comprising the homopentameric scaffold of PbaA and C-terminal segment of PbaB and subjected them to proteasome-activating assays as well as small-angle X-ray scattering and high-speed atomic force microscopy. The results indicated that the open conformation and consequent proteasome activation activity could be enhanced by replacement of the crystallographically disordered C-terminal segment of PbaA with the corresponding disordered segment of PbaB. Moreover, these effects can be produced just by incorporating two glutamate residues into the disordered C-terminal segment of PbaA, probably due to electrostatic repulsion among the negatively charged segments. Thus, we successfully endowed a functionally undefined protein with proteasome-activating activity by modifying its C-terminal segment.

PubMed: 29301037
DOI: 10.1093/protein/gzx066

Experimental method

X-RAY DIFFRACTION (2.55 Å)