A ninaE fragment containing 2.5kb of promoter sequence, the transcription start site and 33bp of the 5' untranslated region is fused upstream of Lpol\Ops1 sequences, which consist of 180bp of 5' untranslated sequence and the coding region for amino acids 1-362 (out of 367 in total). The Lpol\Ops1 coding sequence is tagged at the C-terminal end with Tag:Rho1D4. 650bp of the 3' end of the ninaE gene (including the polyadenylation signal) are also present.