An analogue of the DnaJ molecular chaperone whose expression is controlled by sigma s during the stationary phase and phosphate starvation in Escherichia coli.
The Escherichia coli CbpA protein appears to be an analogue of the molecular chaperone, DnaJ, as judged from not only its structure but also its possible function. The expression of cbpA, however, was not significantly affected by up-shift of the growth temperature. Remarkably, it was found that the expression of cbpA was induced under certain growth conditions, such as the entry of cells into stationary phase, or growth in a phosphate-limited medium. Such conditional expression of cbpA was regulated at the transcriptional level in a sigma s-dependent manner. The structure of this sigma s-dependent cbpA promoter was clarified by determining its transcription start site. The cbpA promoter region was found to contain an unusual DNA structure (i.e. DNA curvature). From these results, it was suggested that, in contrast to DnaJ, CbpA may function as a molecular chaperone in an adaptive response to environmental stresses other than heat shock.
Yamashino
T
T
Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Japan.
Kakeda
M
M
Ueguchi
C
C
Mizuno
T
T
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000502:physiology*; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics; D006358:Hot Temperature; D018832:Molecular Chaperones / Q000096:biosynthesis* / Q000235:genetics; D008969:Molecular Sequence Data; D010710:Phosphates / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012808:Sigma Factor / Q000502:physiology*; D014158:Transcription, Genetic
D001426:Bacterial Proteins; C085674:CbpA protein, E coli; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D010710:Phosphates; D011993:Recombinant Fusion Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria