The plasmids pJL3 and pSW1 express the Bacteriocin Release Protein (BRP), which initiates release of periplasmic and cytoplasmic E.coli proteins into the culture medium. Being compatible with most of the commonly used expression vector systems (e.g. ColE1 vectors like pAX, PheBo, pBR322 derivatives), BRP vectors can be co-transformed with the vector producing the recombinant protein of interest. Induction of the BR-Protein with IPTG (pJL3) or mitomycin C (pSW1) will cause an activation of phospholipase A in the outer E.coli membrane. This results in the formation of permeable zones in the cell membranes, through which proteins are released into the medium. A moderate induction prevents lysis of producer cells, also making the system suitable for large-scale protein production in a continuous culture. Since cloned proteins are no longer accumulated in the cytoplasm, problems associated with lethality of recombinant proteins, their preferential degradation or inclusion body formation are avoided.
For your convenience, we also provide competent cells already transformed with one of the vectors.
- vectors expressing the Bacteriocin Release Protein (BRP)
- protein excretion into E. coli culture medium without the need of a signal sequence
- release of lethal proteins
- preventing protein degradation by cytoplasmic proteinases
- avoiding inclusion bodies
- release of periplasmic proteins
- large-scale biotechnological production of proteins in a continuous culture
- simplified protein purification from culture medium
- vectors can be co-transformed with ColE1 vectors alternatively we offer competent BRP-transformed cells
Proteins, which have already been successfully released by activity of BRP from the E.coli periplasm are: