A ColE1-compatible expression vector for the production of His-tagged fusion proteins

Plasmid pDB31 is a ColE1-compatible expression vector based on the p15A ori gin of replication. It is designed to express His-tagged fusion proteins in cells co-hosting a compatible expression vector. It was constructed by ass embling the operator/promoter region plus the 6xHis and the multiple clonin g site of pQE31 (QIAGEN) with the p15A origin of replication plus Kan(R) of pGP1-2. The plasmid was found to be stable in Escherichia coli strains BL2 1 and DH11S. It was used to produce and purify the ferredoxin reductase com ponent of Comamonas testosteroni B-356 biphenyl dioxygenase inside a clone hosting the remaining dioxygenase genes on a compatible plasmid.