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          Institute: MPI für Biochemie     Collection: Structural Biology (W. Baumeister)     Display Documents

ID: 318492.0, MPI für Biochemie / Structural Biology (W. Baumeister)
The atp-dependent hsivu protease from escherichia coli is a four-ring structure resembling the proteasome
Authors:Rohrwild, M.; Pfeifer, G.; Santarius, U.; Müller, S. A.; Huang, H. C.; Engel, A.; Baumeister, W.; Goldberg, A. L.
Date of Publication (YYYY-MM-DD):1997-02
Title of Journal:Nature Structural Biology
Issue / Number:2
Start Page:133
End Page:139
Audience:Not Specified
Abstract / Description:HslVU is a new two-component protease in Escherichia coli composed of the proteasome-related peptidase HslV and the ATPase HslU. We have used electron microscopy and image analysis to examine the structural organization of HslV and HslU homo-oligomers and the active HslVU enzyme. Electron micrographs of HslV reveal ring-shaped particles, and averaging of top Views reveal six-fold rotational symmetry, in contrast to other beta-type proteasome subunits, which form rings with seven-fold symmetry. Side views of HslV show two rings stacked together, thus, HslV behaves as dodecamer. The ATPase HslU forms ring-shaped particles in the presence of ATP, AMP-PNP or ADP, suggesting that nucleotide binding, but not hydrolysis, is required for oligomerization. Subunit crosslinking, STEM mass estimation, and analysis of HslU top views indicate that HslU exists both as hexameric and heptameric rings. With AMP-PNP present, maximal proteolytic activity is observed with a molar ratio of HslU to HslV subunits of 1:1,and negative staining electron microscopy shows that HslV and HslU form cylindrical four-ring structures in which the HslV dodecamer is flanked at each end by a HslU ring. [References: 45]
Free Keywords:Transmission electron-microscopy; Molecular-weight proteases; Heat-shock protein; Clp protease; Specificity component; Degrades; Complex; System; 20s; Degradation.; Biochemistry & biophysics.
External Publication Status:published
Document Type:Article
Communicated by:Anton Hillebrand
Affiliations:MPI für Biochemie/Structural Biology (W. Baumeister)/
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