Abstract
It is reported that NifS or IscS (a homolog of NifS) protein in Azotobacter vinelandii and Escherichia coli are involved in assembly of iron sulfur (FeS) protein. It is thought that mobilizing sulfur from free cystein is incorporated into apo-FeS protein to form FeS cluster by NifS or IscS. IscS homolog was also reported from oxygenic photosyntetic bacteria, cyanobacteria Synechosystis PCC 6803. Whole genome sequence of Green sulfur Bacterium Chlorobium tepidum revealed that the putative iscS is present on the genome of C. tepidum. Phylogenetic analysis indicate that the iscS of C. tepidum is classified with different from those of E. coli and cyanobacteria. To investigate the function of iscS of C. tepidum, we over-expressed iscS using His-tagged expression vector in E. coli. The biochemical function of purified protein from E. coli will be reported.
