Part:BBa_K4202045

Sucrose regulated kill switch in Bacillus subtilis

Sucrose-induced promoters are linked to the toxin/antitoxin system. When the sucrose concentration is high enough, the promoter is efficient, and MazE continuously expresses the antagonistic toxin MazF; When the sucrose concentration is insufficient, the promoter efficiency is insufficient, MazE cannot be expressed continuously, and based on its instability, its cell concentration will decrease faster than MazF, causing MazF to exert its toxic effects and eventually lead to cell death. This part prevents engineering bacteria from escaping into the environment under certain stressful conditions.

Biology

The positive regulatory promoter PsacB is a weak endogenous promoter and can be induced by the sucrose [1]. It contains two parts, the core constitutive promoter and the leader RNA sequence. The leader RNA sequence contains a terminator overlaping with the binding site of sacY [2] [3]. When the sucrose existed, the sacY can bind to the bing site in the leader RNA and stablized the terminator, which enables the transcription. The absence of sucrose can lead to the formation of terminator structure, which will lead to the early termination. The antitoxin-toxin system is consisted by the coding sequence mazE and mazF. The mazF sequence used in our project is from E. coli and can degrade the

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 926
  Illegal AgeI site found at 654
  
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal SapI.rc site found at 1139