A novel dnaK operon from Porphyromonas gingivalis

The nucleotide sequence of the dnaK operon cloned from Porphyromonas gingiv alis revealed that the operon does not contain homologues of either dnaJ or grpE. However, there were two genes which encode small heat shock proteins immediately downstream from the dnaK and they were transcribed together wi th dnaK as one unit. The ATPase activity of the P, gingivalis DnaK was syne rgistically stimulated up to 40-fold in the simultaneous presence of Escher ichia coli DnaJ and GrpE, These results suggest that the DnaK homologue of P, gingivalis, with its unique genetic structure and evolutionary features, works as a member of the DnaK chaperone system. (C) 1999 Federation of Eur opean Biochemical Societies.