High-level expression and epitope localization of the major outer membrane protein of Chlamydia trachomatis serovar L1

Fragments of the gene encoding the major outer membrane porin protein (MOMP) of Chlamydia trachomatis serovar L1 were ligated into the pUC plasmid vectors to give a series of overlapping recombinants expressing MOMP from the lac promoter. Induction of this promoter with IPTG leads to high-level expression of the recombinant porin protein. Electron microscopy shows the presence of insoluble inclusions within the Escherichia coli host cells. Probing the expressed MOMP fragments with a set of monoclonal antibodies permitted localization of the four binding sites (epitopes) of primary-sequence-dependent monoclonal antibodies that exhibit genus-, species-, subspecies- and type (serovar)-specific reactivities.