Difference between revisions of "Part:BBa K3606905"

Revision as of 22:50, 27 October 2020

P5 driven mcbABCD

BBa_K3606104 is one of a series of composite parts designed to screen a suitable strength promoter for mcbABCD.

Usage and Biology:

P5, which is a constitutive promoter, will continuously drive expression of mcbABCD. McbABCD is responsible for producing MccB17.

Design:

In our design the proper expression level of mcbABCD is very important. Since its product MccB17 acts as antibiotic, its low expression will make it unable to kill the surrounding bacteria and cannot improve its competitiveness in the intestine. But considering its toxicity, its high expression will also increase the burden of survival of engineered bacteria. So we need to test a collection of promoters, and find the most suitable one for it.

Characterization:

In order to prove the efflux and immune effects of McbEFG, we compared E.coli with mcbABCD-mcbEFG-ptetR and E.coli with mcbABCD to observe the difference of their antibacterial effects. We mixed WT E.coli (expressing GFP driven by plac) and E.coli with mcbABCD-mcbEFG-ptetR in different ratios (5:7 20:7 50:7), and measured the OD value of the bacteria two hours after adding an inducer, which can be used to reflect the antibacterial effect of antimicrobial peptides. We followed the same method as above to mix WT E. coli and E.coli with merely mcbABCD, induce and measure the OD value.

Further Application:

To use this part, simply clone it into a low-copy plasmid vector, transfer into E.coli, incubate overnight. You can also understand the strength of P5 through my experimental results.

Sequence and Features