Difference between revisions of "Part:BBa K3788016"

Latest revision as of 23:51, 21 October 2021

Optimized Timer-lysis device

Introduction  :

This part contains the optimized timer lysis device. It is composed of a fragment of the cal gene encoding the CaL lysis protein. It also contains the caa and cai genes coding respectively for the ColA toxin (colicin A) and the CaI immunity protein.

In nature, the caa and cai genes are in operon, and the gene encoding the immunity protein is constitutively expressed and is found on the antisense strand of the operon. The regulation of this system is complex and contains many regulatory elements.

This system is located on a plasmid present in certain populations of wild E. coli. It induces the accumulation of ColA toxin in the host cell and then causes the latter to die by the action of the lysis protein. This releases ColA into the medium and kills cells that do not have the immunity gene present on this plasmid.

The cal gene encodes the CaL protein, a 28 to 41 residue lipopeptide, which is produced as a precursor and then processed. When mature, it forms pores in the membrane, causing the host to near lysis and the leakage of cellular components into the medium.

Design 2  :

The BBa_K3788016 part is an improvement of the BBa_K3788015 part. It contains a larger 5 'fragment of the caa coding sequence, which allows to keep regulatories elements believed to be involved in the regulation of lysis protein, resulting in loss of bacterial lysis.

This additional caa portion contains an alternative LexA binding box which has been identified in silico using virtual footprint (https://www.prodoric.de/vfp). This corresponds to an alternative promoter.

The design of this part allows the construction of the composite part BBa_K3788023 which is none other than the composite part BBa_K3788019 having undergone an engineering cycle

Sequence and Features