DK1622 Coordinates Expressions of the Duplicate and Single Genes for Synergistic Functions of GroELs and GroES.

Chaperonin GroEL (Cpn60) requires cofactor GroES (Cpn10) for protein refolding in bacteria that possess single and genes in a bicistronic operon. Among 4,861 completely-sequenced prokaryotic genomes, 884 possess duplicate genes and 770 possess genes with no neighboring . It is unclear whether stand-alone requires in order to function and, if required, how duplicate genes and unequal genes balance their expressions. In DK1622, we determined that, while duplicate s were alternatively deletable, the single that clusters with was essential for cell survival. Either GroEL1 or GroEL2 required interactions with GroES for and functions. Deletion of or resulted in decreased expressions of both and ; and ectopic complementation of recovered not only the but also expressions. The addition of an extra gene upstream to form a bicistronic operon had almost no influence on expression and the cell survival rate, whereas over-expression of using a self-replicating plasmid simultaneously increased the expressions. The results indicated that DK1622 cells coordinate expressions of the duplicate and single genes for synergistic functions of GroELs and GroES. We proposed a potential regulation mechanism for the expression coordination.