Part:BBa_K174017

CadA promoter with CzrA binding site

In B. subtilis CadA system works as an efflux system to take the metals out in the cell. It is normally repressed by the CzrA (formely YozA) repressor protein.

When metals such as copper, zinc and arsenic are present inside the cell, they can bind to CzrA and derepress the promoter expressing CadA. Hence metals are taken out by the efflux system.

By utilising the promoter from the CadA system, we created a metal sensor, that responds to at least these three metals.

Usage and Biology

CzrA function: (Gaston Day School 2021)

Different metals can induce CzrA’s transcription, including Zn(II) Ag(I), Cd(II), Co(II), Ni(II). In the research of the chromosome of Staphylococcus aureus, it was found that CzrA is an autorepressor to the operon, and has the ability to bind to certain operon regions. Also, the binding of CzrA with Zn2+ is possibly determined by the concentration of zinc ion to activate the transcription and cause the bound form to release. However, the transcription might be interrupted by the heat-shock stimulation because the structure of CzrA is destroyed at the binding site.

Additional references for this promoter:

Moore, C. M., Gaballa, A., Hui, M., Ye, R. W., and Helmann, J. D., (2005). Genetic and physiological responses of Bacillus subtilis to metal ion stress. Mol. Microbio. 57(1):27-40.

Rowen, B. P., Weigel, U., Karkaria, C., and Gangola, P., (1988). Molecular characterization of an anion pump. J Biol Chem 263(7):3067-3070.

Tsai, K., Hsu, C., and Rosen, B. P., (1997). Efflux mechanisms of resistance to cadmium, arsenic, and antimony in prokaryotes and eukaryotes. Zoo. Studies 36(1):1-16.

Tsai, K., Yoon, K. P., and Lynn, A. R., (1991). ATP-dependent cadmium transport by the cadA cadmium resistance determinant in everted membrane vesicles of Bacillus subtilis. J Bacteriol 174(1):116-121.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  INCOMPATIBLE WITH RFC[12]

  Illegal NheI site found at 166
  
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]