The pASG-IBA144 vector is designed for expression of recombinant proteins with an N-terminal Twin-Strep-tag® and C-terminal His-tag in E. coli. The vector carries an ampicillin resistance cassette for selection of transformed E. coli cells, F1 and ColE1 origin for a high plasmid copy number, the inducible tetracycline promoter/operator for the regulated expression of proteins, and the ompA signal for periplasmic secretion of the recombinant protein. The vector can be combined with any E. coli strain since the tet-promoter works independently of the genetic background of E. coli. Expression of the recombinant protein is induced by addition of anhydrotetracycline, which is a derivative of tetracycline that does not exhibit antibiotic activity. During the secretion into the periplasmic space the ompA signal sequence will be cleaved off. Please note that cloning into pASG-IBA Acceptor Vectors compulsorily requires the restriction enzyme Esp3I since no other MCS for the integration of a gene of interest is available. In addition to the direct cloning of the gene of interest into pASG-IBA vectors with Esp3I, another option via a so-called Entry Vector is possible.