Characterization of the molecular chaperone ClpB from the pathogenic spirochaete < i > Leptospira interrogans < /i >

by Joanna Krajewska, Anna Modrak-W ójcik, Zbigniew J. Arent, Daniel Więckowski, Michal Zolkiewski, Agnieszka Bzowska, Sabina Kędzierska-MieszkowskaLeptospira interrogans is a spirochaete responsible for leptospirosis in mammals. The molecular mechanisms of theLeptospira virulence remain mostly unknown. Recently, it has been demonstrated that an AAA+ chaperone ClpB (a member of the Hsp100 family) fromL.interrogans (ClpBLi) is not only essential for survival ofLeptospira under the thermal and oxidative stresses, but also during infection of a host. The aim of this study was to provide further insight into the role of ClpB in the pathogenic spirochaetes and explore its biochemical properties. We found that a non-hydrolysable ATP analogue, ATP γS, but not AMP-PNP induces the formation of ClpBLi hexamers and stabilizes the associated form of the chaperone. ADP also induces structural changes in ClpBLi and promotes its self-assembly, but does not produce full association into the hexamers. We also demonstrated that ClpBLi exhibits a weak ATPase activity that is stimulated by κ-casein and poly-lysine, and may mediate protein disaggregation independently from the DnaK chaperone system. Unexpectedly, the presence ofE.coli DnaK/DnaJ/GrpE did not significantly affect the disaggregation activity of ClpBLi and ClpBLi did not substitute for the ClpBEc function in theclpB-nullE.coli strain. This result underscores the species-specificity of the ClpB cooperation with the co-chaperones a...
Source: PLoS One - Category: Biomedical Science Authors: Source Type: research