Abstract
Hsp90 is one of the most abundant proteins in the cytosol of various eucaryotic cells. We reported last year that cyanobacterial HtpG, a prokaryotic homolog of Hsp90, can interact with the 30kDa linker polypeptide of phycobilisome. In the present study, we performed experiments in order to find a region(s) of HtpG with which the linker interacts. The structure of HtpG can be divided into three domains, N-terminal domain, middle domain, and C-terminal domain. We made E. coli constructs that overexpress N-terminal domain, N-terminal and middle domains, middle and C-terminal domains, or C-terminal domain of cyanobacterial HtpG. In order to evaluate in vitro interaction between the linker and HtpG, we monitored the aggregation of the linker at 45oC for 15 min by light scattering assays. The results indicate that the N-terminal and/or middle domains interact the linker.
