Improvement in pHERD vectors to express recombinant proteins tagged with hexahistidine at either the NH₂- or COOH- terminal in Pseudomonas aeruginosa

Abstract

We constructed pHERDHis vectors to express polyhistidine-tagged proteins based on the pHERD vectors. The oligonucleotides containing the hexahistidine sequence were designed to be able to introduce the tag at either the NH2- or COOH- terminal. To demonstrate the usefulness of the vectors, a pyocyanin biosynthetic protein, PhzS, was expressed in a pyocyanin-deficient mutant of Pseudomonas aeruginosa. In the mutant strain, both HisPhzS (tag at the NH2- terminal) and PhzSHis (tag at the COOH- terminal) worked as a functional protein and pyocyanin was produced. It was also demonstrated that HisPhzS was purified by standard affinity chromatography.