The ATPase domain of HscC (DnaK homolog) is essential for interfering sigma70 activity in E. coli.
HscC, a DnaK homolog in Escherichia coli, consists of adenosine triphosphatase (ATPase), substrate-binding and C-terminal domains. Overexpression of HscC markedly inhibits growth of host cell and reduces the sigma(70)-dependent promoter activity presumably by forming a complex with sigma(70). To identify the region(s) of HscC responsible for growth inhibition and complex formation with sigma(70), domain swapping experiments were carried out between DnaK and HscC. Thus the chimeric proteins carrying the ATPase domain of HscC and substrate-binding domains of either HscC or DnaK were found to inhibit the growth of the cell, reduce the sigma(70)-dependent promoter activity and form a complex with sigma(70). These results indicate that the ATPase domain of HscC rather than the substrate-binding domain is important for determining its functional specificity.
Arifuzzaman
Mohammad
M
Department of Cell Biology, NARA Institute of Science and Technology, Ikoma, Japan.
Oshima
Taku
T
Mori
Hirotada
H
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012808:Sigma Factor / Q000378:metabolism*
D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D011993:Recombinant Fusion Proteins; D012808:Sigma Factor; C114584:hscC protein, E coli; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; D000251:Adenosine Triphosphatases; C063842:dnaK protein, E coli