Difference between revisions of "Part:BBa K2377014"

Revision as of 17:08, 27 October 2017

zarp, zinc two-component relulatory system

Improved target: BBa_K1755301（K1755024、K1755305、K1755303）

Improved form We replaced a sensor element（Copper-Responsive Two-Component System BBa_K190017）for the Zinc-Responsive Two-Component regulatory system (contains σ54 promoter).

Mechanism of changed sensor The mechanism of Zinc sensor is related to a intrinsic signaling pathway in Ecoli. Which is known that many sensing proteins ZraS immobilized on the membrane of cell. And when Zn2+ show up in periplasmic space, the ions will combine with ZraS and trigger it autophosphorylation. (ZraS*) The phosphorylation signal will transmit from ZraS* to ZraR, then ZraR* come to ZraR(HydG) binding site[1] that will make σ54promoter start downstream transcription. (ZraS* ,ZraR* means activated condition.)

     Figure 1   the composition of Zinc-Responsive Two-Component regulatory system

So, we substitute Zinc-Responsive Two-Component regulatory system for the copper one in BBa_K1755301. Successfully construct a new heavy metal sensor.

Function of improved new part Improved new part is BBa_K2377009, which can detect the concentration of Zn2+ and transform it into electric signal.

The downstream protein ribB (3,4-dihydroxy-2-butanone 4-phosphate synthase ,ribB) could catalyze the conversion of D-ribulose 5-phosphate formate to 3,4-dihydroxy-2-butanone 4-phosphate. This step is part of the biosynthesis pathway of riboflavin, an electron carrier in microfunction circuit (MFC).

So when the whole gene circuit works, it will result in a consequence that once the concentration of Zn2+ in environment increased, more riboflavin will be produced to impact the voltage of MFC.

Through this new part we realized monitoring heavy metal Zn2+ automatically, quantitatively and efficiently.

The figure below shows the comparison of the part BBa_K1755301 (left) with the new improved part BBa_K2377009 (right), the riboflavin concentration versus heavy metal ion concentration.

Reference

[1] Leonhartsberger S, Huber A, Lottspeich F, et al. The hydH/G Genes from Escherichia coli code for a zinc and lead responsive two-component regulatory system.[J]. Journal of Molecular Biology, 2001, 307(1):93-105. [2] Munson GP1, Lam DL, Outten FW, O'HalloranTV. Identification of acopper-responsive two-component system on the chromosome of Escherichia coli K-12. [3] PedorolluD1,2, The ribB FMN riboswaith from Escherichia coli operates at the transcriptional and translational level and regulates riboflavin biosynthesis. FEBS J. 2015 Aug;282(16):3230-42. doi: 10.1111/febs.13226. Epub 2015 Feb 27.

Sequence and Features