Designed by: Julia Mller   Group: iGEM11_Freiburg   (2011-09-15)

strong Promoter and strong RBS

You can insert your gene of interest behind this part.
If you want a functional protein you need a promotor and a ribosome binding site for proper gene expression.

Usage and Biology

Slovenia HS team characterized this part in 2015.

The part was fused with our own BioBricks containing a coding region and a double terminator. The parts used were K1669002, which contains CtfA with His-tag, K1669005, which contains CtfB with His-tag, and K1669006, which contains BdhB with His-tag. To evaluate the activity of the promoter and RBS, proteins were expressed.

Escherichia coli DH5α bacteria were transformed with the expression plasmids and grown in shaker flasks at 37 °C in LBC medium overnight. 1 ml samples were taken for analysis. Cells were collected by centrifugation at 6000g for 10 min and resuspended in 100 µl of H20. 10 µl samples were taken and 5 µl of SDS-PAGE loading buffer was added. Samples were cooked at 100 °C for 10 min and resolved on 12% SDS-PAGE gel.

203px-PraviSDSctfA.jpeg 237px-SdsCtfB.jpeg 215px-SdsBdhB.jpeg

The proteins were successfully expressed and were entirely in the insoluble fraction, mostly likely due to the strength of the promoter and RBS. The procedure for checking expression was then repeated with bacteria grown at 20 °C and 16 °C, at which point some protein was observed in the soluble fraction as well.

Proteins were detected using Western blot as well. 12% SDS-PAGE gels were electroblotted for 1, 5 hours at 200 V, blocked in non-fat dry milk overnight and incubated the next day in two steps. A dilute solution of primary antibody was incubated with the membrane under gentle agitation for an hour. Then a dilute solution was incubated with the membrane under gentle agitation for an hour as well. The hydrogen peroxide method was for visualization.

188px-MembranaCtfB.jpeg 200px-MembranaCtfA%28vresniciB%29.jpeg 200px-MembranaBdhB.jpeg

Sequence and Features

Assembly Compatibility:
  • 10
  • 12
    Illegal NheI site found at 7
    Illegal NheI site found at 30
  • 21
  • 23
  • 25
  • 1000

Functional Parameters

Functional Parameters: Austin_UTexas

Burden Imposed by this Part:

Burden Value: 8.5 ± 5.1%

Burden is the percent reduction in the growth rate of E. coli cells transformed with a plasmid containing this BioBrick (± values are 95% confidence limits). This part exhibited a significant burden. Users should be aware that BioBricks with a burden of >20-30% may be susceptible to mutating to become less functional or nonfunctional as an evolutionary consequence of this fitness cost. This risk increases as they used for more bacterial cell divisions or in larger cultures. Users should be especially careful when combining multiple burdensome parts, as plasmids with a total burden of >40% are expected to mutate so quickly that they become unclonable. Refer to any one of the BBa_K3174002 - BBa_K3174007 pages for more information on the methods and other conclusions from a large-scale measurement project conducted by the 2019 Austin_UTexas team.

This functional parameter was added by the 2020 Austin_UTexas team.