Characterization of the HslU chaperone affinity for HslV protease

M. Kamran Azim, Walter Goehring, Hyun Kyu Song, Ravishankar Ramachandran, Matthias Bochtler, Peter Goettig

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The HslVU complex is a bacterial two-component ATP-dependent protease, consisting of HslU chaperone and HslV peptidase. Investigation of protein-protein interactions using SPR in Escherichia coli HslVU and the protein substrates demonstrates that HslU and HslV have moderate affinity (Kd = 1 μM) for each other. However, the affinity of HslU for HslV fivefold increased (Kd ∼ 0.2 μM) after binding with the MBP-SulA protein indicating the formation of a "ternary complex" of HslV-HslU-MBP-SulA. The molecular interaction studies also revealed that HslU strongly binds to MBP-SulA with 10-9 M affinity but does not associate with nonstructured casein. Conversely, HslV does not interact with the MBP-SulA whereas it strongly binds with casein (Kd = 0.2 μM) requiring an intact active site of HslV. These findings provide evidence for "substrate-induced" stable HslVU complex formation. Presumably, the binding of HslU to MBP-SulA stimulates a conformational change in HslU to a high-affinity form for HslV.

Original languageEnglish
Pages (from-to)1357-1362
Number of pages6
JournalProtein Science
Issue number5
Publication statusPublished - 2005 May 1


ASJC Scopus subject areas

  • Biochemistry

Cite this

Azim, M. K., Goehring, W., Song, H. K., Ramachandran, R., Bochtler, M., & Goettig, P. (2005). Characterization of the HslU chaperone affinity for HslV protease. Protein Science, 14(5), 1357-1362.