An Inducible T7 Polymerase System for High-Level Protein Expression in Diverse Gram-Negative Bacteria.

A broad host range (BHR)-inducible T7 RNA polymerase system was developed, enabling induction with isopropyl-β-d-thiogalactopyranoside (IPTG), similar to the Escherichia coli strain BL21(DE3) protocol, but it is now applicable in a wide range of bacteria. This system allows for high protein yields and purification from diverse Gram-negative bacteria, including the native host.