Abstract
We have previously identified multigene family of the molecular chaperone dnaK (dnaK1, 2 , 3) and dnaJ (dnaJ1, 2, 3, 4) in the genome of unicellular cyanobacterium Synechococcus sp. PCC7942. We have found that, among seven genes, DnaK2, K3, J1, J2 and J3 are essential for nomal growth. In order to explore specific functions of these DnaK and DnaJ, we first analysed the expression profiles of each gene under various stress conditions. The results indicated that dnaK2 and dnaJ2 increased remarkably under heat or high-light stress. The results obtained suggested that each dnaK and dnaJ are differently regulated and may have distinct function under a stress conditions. Finally, we are interested in the partnership among multiple DnaK and DnaJ whether there is a specificity between the two structurally related proteins. We observed some specificity between them and the results will be discussed in the viewpoint of chaperone functions.
