Hsp104 and ClpB are hexameric ATPases that resolubilize aggregated proteins in collaboration with the Hsp70 chaperone system. Hsp104/ClpB functionally interact only with their respective Hsp70 system and this specificity is mapped to the Hsp104/ClpB coiled-coil domain (CCD). We hypothesize that the interaction between Hsp70 and Hsp104/ClpB CCD stimulates nucleotide exchange and release of substrate from Hsp70. In the current study, the CCDs of E. coli ClpB and S. cerevisiae Hsp104 have been purified. Isolated domains are monomeric and well folded. They inhibit refolding of aggregated firefly luciferase in a species-specific manner. We found that the ATPase activity of E. coli DnaK is stimulated at low concentrations of the E. coli ClpB CCD but not by yeast Hsp104 CCD. However, in another bacterial system (Thermus thermophilus) we found that the ClpB CCD inhibits The ATPase activity of DnaK suggesting that the interaction may have different consequences in distinct chaperone networks.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/35128 |
| Date | 18 March 2013 |
| Creators | Moradi, Shoeib |
| Contributors | Glover, John R. |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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