Abstract
In eukaryotic cells, Hsp90 has been shown to play important roles in regulation of several important cellular processes such as signal transduction pathways, but a role of HtpG, an Hsp90 homologue in bacteria, is not clear yet.
We have demonstrated that HtpG plays roles under various stresses such as heat and oxidative stresses in the cyanobacterium Synechococcus sp. PCC 7942 and the amount of phycocyanin and chlorophyll is reduced in an htpG mutant. We have been searching for in vivo targets for HtpG.
By yeast two hybrid screening analysis, we discovered that the HtpG interacted with uroporphyrinogen decarboxylase (HemE). This enzyme plays an essential role in heme and chlorophyll biosynthesis.
To study the interaction between HemE and HtpG in vitro, recombinant proteins of His-tagged HtpG and HemE were over-expressed in E. coli, and purified. Studies on the interaction between these proteins by pull-down assays or the complex are in progress.
