Part:BBa_K1992005

Tar native RBS expression system (promoter+RBS+coding+terminator)

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  INCOMPATIBLE WITH RFC[12]

  Illegal NheI site found at 7
  Illegal NheI site found at 30
  
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal AgeI site found at 1355
  
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal SapI.rc site found at 184
  

Introduction

Tar chemoreceptor is one of four native chemoreceptors of E.coli, it is mediate chemotaxis response towards aspartate and away from Ni and Co (1). This device allows the expression of a functionally native Tar chemoreceptor.

Usage and biology

This device is very similar to our BBa_K1992004 device it is only differ by its RBS. Here the expression system is using the native RBS of the Tar receptor as found in the E.coli genome (BBa_K1992000).

Expriments and results

In order to test the device it was transformed to chemoreceptor free strain (UU1250) and tested for chemotaxis ability using [http://2016.igem.org/Team:Technion_Israel/Experiments swarming assay]. As can be seen in figure 1 the cells expressing the Tar chemoreceptor create a halo indicating a functional chemotaxis result.The larger radius of the native RBS suggests a higher expression of Tar, that might raise the sensitivity of the chemotaxis system(Figure 2) (2).

Fig1: Tar expression using the native RBS in UU1250 strain, resulting in a halo indicating a functional chemotaxis response. b. Negative control - UU1250 strain w/o the Tar expression plasmid. c. Positive control - ΔZ strain expressing all chemoreceptors.

Fig2: Comparison between our two new strains UST and UNT: a. UST strain - with the plasmid K1992004. b. UNT strain - with the plasmid K1992005.

Reference

1.BI, Shuangyu; LAI, Luhua. Bacterial chemoreceptors and chemoeffectors.Cellular and Molecular Life Sciences, 2015, 72.4: 691-708.
‏ 2.SOURJIK, Victor; BERG, Howard C. Functional interactions between receptors in bacterial chemotaxis. Nature, 2004, 428.6981: 437-441.‏