Abstract
The 90-kDa heat shock proteins (Hsp90s) are a widespread family of molecular chaperones found in bacteria and all eukaryotes. Eukaryotes require a cytoplasmic Hsp90 for viability under all conditions tested. Like other major chaperones such as Hsp70 and Hsp60, Hsp90 has a weak ATPase activity. Structural analysis of Hsp90 and HtpG, a prokaryotic member of Hsp90, has revealed dynamic, ATPase-coupled conformational changes. However, the ATPase-coupled chaperone mechanism is largely unknown. We showed that HtpG is essential for the thermal stress management in cyanobacteria in contrast to Escherichia coli and Bacillus subtilis. We also reported at the last meeting that HtpG interacts with a linker polypeptide of the phycobilisome from the cyanobacterium Synechococcus sp. PCC 7942. In this presentation, I will show the effect of nucleotides and nucleotide analogs on the suppression of heat inactivated linker polypeptides by HtpG.
