HslV-HslU: A novel ATP-dependent protease complex in Escherichia coli related to the eukaryotic proteasome.

• DOI: 10.1073/pnas.93.12.5808
• Publication Date: 2002-07-26T14:36:44Z
• Authors: M Rohrwild; O Coux; H C Huang; R P Moerschell; S J Yoo; J H Seol; C H Chung; A L Goldberg
• Keywords: AAA proteins

We have isolated a new type of ATP-dependent protease from Escherichia coli. It is the product heat-shock locus hslVU that encodes two proteins: HslV, 19-kDa protein similar to proteasome beta subunits, and HslU, 50-kDa related ATPase ClpX. In presence ATP, hydrolyzes rapidly fluorogenic peptide Z-Gly-Gly-Leu-AMC very slowly certain other chymotrypsin substrates. This activity increased 10-fold in E. coli expressing proteins constitutively 100-fold cells HslV HslU high copy plasmid. Although could be coimmunoprecipitated cell extracts both strains with an anti-HslV antibody, these components were readily separated by various types chromatography. ATP stimulated peptidase up 150-fold, whereas nucleoside triphosphates, nonhydrolyzable analog, ADP, or AMP had no effect. Peptidase was blocked antibody several inhibitors eukaryotic (a threonine protease) but not classes proteases. Unlike proteasomes, HslVU lacked tryptic-like peptidyl-glutamyl-peptidase activities. Electron micrographs reveal ring-shaped particles en face images 20S ClpAP protease. Thus, appear form complex which hydrolysis essential for proteasome-like component HslV.