BBa_K2522000 is a plasmid containing a genetic sequence that expresses CsgA and dCBD continuously. The final product was developed in several steps. A part from the iGEM Distribution Kit, BBa_K1321340, was used. This part is the genetic code for a double cellulose binding domain, which functions to attach an organism to cellulose. The second piece of genetic code used was the csgA gene.
csg (curli specific gene) followed by a letter of the alphabet refers to the genes involved in expressing curli fibers. Curli fibers are hair-like strands of proteins generated by certain strains of E. coli on the outer membrane of the bacteria. These proteins encompass the bacteria in a fibrous mesh. csgA in particular indicates the individual building blocks of the fibers.
To construct the part, the genetic code for csgA was removed from the genomic DNA of E. coli Nissle and the dCBD was taken from the Distribution Kit. The genes were combined in a plasmid with the stop codon removed from the code for csgA. Using this process, the csgA flows directly into the dCBD, so that every time a CsgA unit is produced, a dCBD unit is attached to the csgA. Because of this, the mesh of curli fibers that encompasses the microbe can bind to cellulose so that the microbe is encapsulated in cellulose.