A novel Escherichia coli lipoprotein expression vector

A novel Escherichia coli (Ec) lipoprotein expression plasmid, pSJLP, was constructed. The plasmid contains a truncated alkaline phosphatase gene (phoA) located downstream from the Lac repressor gene lacI q and the IPTG inducible p tac promoter. The phoA gene was truncated by deleting the native phoA signal sequence and fusing the truncated phoA gene to the lipoprotein signal sequence of the major Ec lipoprotein LPP. The recombinant LPP::PhoA fusion protein is produced and processed as a lipoprotein and can therefore be used as substrate for a novel signal peptidase II assay.