ScarabXpress is the latest strain in the multiple-deletion series (MDS) of Scarab Genomics Clean Genome® E. coli. Based on the MDS™42 strain, ScarabXpress T7lac contains a chromosomal copy of the T7 RNA polymerase gene expressed from a unique, tightly controlled lac promoter.
MDS™42 is a K-12 strain with a 15% genome reduction to remove non-essential genes, sequences for recombinogenic and mobile DNA, and cryptic virulence genes, while preserving robust growth and protein production. Scarab has removed Insertion sequence (IS) elements, which are a prevalent, but frequently overlooked, problem that contributes to clonal instability. In addition, Clean Genome® strains lack prophage, which can be stress-activated and cause premature lysis and failed runs during fermentation. Genome reduction optimizes Clean Genome E. coli for recombinant DNA and protein production, providing enhanced genetic stability and improved metabolic efficiency, and making them the strains of choice for applications ranging from routine cloning to manufacturing biotherapeutics.