Part:BBa_K4164018

Contribution

This composite part is used to do further research on the yellow fluorescent protein (YFP), which is commonly used as the reporter of a gene circuit. We chose the Bobrick BBa_K592101 from the iGEM distribution kit and recombined it to plasmid pET-29a+ by homologous recombination. We firstly studied the effect of different concentration of IPTG(Isopropyl-beta-D-thiogalactopyranoside) on the expression of YFP and the fluorescence intensity of bacteria. After that, we also extracted the YFP from the bacteria and identified the effect of temperature on YFP activity.

1. The effects of different concentrations of IPTG on E.coli BL21 containing BBa_K4164018

We compared the inducing effects of IPTG on YFP through different concentrations of IPTG. According to the result data, no significant differences in fluorescence intensity were observed by using different concentrations of IPTG (figure 1). What's more, we could deduce that the leakage expression was very low and the bacteria was sensitive to the IPTG induction. For the first four hours, the fluorescent intensity did not differ much under IPTG induction, among which 0.5mM showed the best. While after 4 hours of incubation, the fluorescence intensity rose sharply, reaching its highest value at the sixth hour, and remained stable with slight fluctuations ever since.

Figure1.The effects of different concentrations of IPTG on E.coli BL21（DE3） containing BBa_K4164018.

2. The effects of temperature on the activity of YFP

There were some differences in the activity of YFP at different temperatures for E. coli BL21(figure 2). The results indicated that YFP activity was higher in low temperatures (eg.4℃,16℃ and 37℃) and lower in higher degrees. According to the curve, the value of fluorescence intensity of YFP firstly witnessed a slow drop from 4℃ to 16℃. Then it climbed steadily and peaked at a point somewhere before 37℃, which met our expectation.

Figure2. The effects of temperature on YFP activity.

Figure3. 4 hours YFP-transformed E. coli strains (Right: control)

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
  COMPATIBLE WITH RFC[25]
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal BsaI.rc site found at 741