Part:BBa_K415301

Low Power Toggle - Ptrc:cI:tt:Plambda:LacI:tt

The original pTSMa plasmid from the Collins paper. This plasmid has been modified so that it now contains cI that is hypersensitive to cleavage by RecA = Low Power Toggle.

From the [http://2010.igem.org/Team:MIT 2010 MIT iGEM Team].

This part is a variation of a [http://www.pnas.org/content/101/22/8414.full|Collins/Kobayashi UV Toggle] (2004) from an article in PNAS. It is a bistable toggle (on or off state) and switching to state 1 is induced by UV exposure and to state 2 is IPTG. If the toggle is set with IPTG, the cells will express cI which will inhibit Plambda. If this is exposed to certain levels of UV (see power modulations) cI is cleaved by Rec-A (a UV induced enzyme) and lacI expression begins and inhibits Ptrc.

This part improves upon its predecessor Part:BBa_K415300 in that it requires less UV power to switch states, thus killing fewer cells (see E.Coli death curve).

E.Coli population density as a function of UV exposure. Measured by drip assay.

This plasmid differs genetically from Part:BBa_K415300 in that its inhibitory lambda cI protein is more sensitive to Rec-A cleavage.

The following data was taken from cells co-transformed with K415301 and Part:BBa_K415069. The cells were grown to mid-log phase in LB broth and 2.65μM IPTG. The IPTG was washed out, the cells concentrated 10x, and then 100uL cells was added 1:40 to melted M9 Agar and allowed to cool in small petri dishes. The plates incubated agar up for 4 hours at 37°C, were exposed under a mask to the corresponding UV power levels, incubated for another 4 hours at 30°C and then imaged.

UV Power Modulation
Photos (in J/m^2)

FACS Data
FACS (in J/m^2)

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 AgeI site found at 1773
  
• 1000
  COMPATIBLE WITH RFC[1000]