The ninaE promoter drives expression of a chimeric trp-trpl fusion protein which is tagged at the N-terminal end with a tag cassette composed of Tag:polyHis, Tag:SBP, Tag:MYC and Tag:CS(TEVp). The chimeric protein consists of trpl amino acid residues 1-335, trp amino acid residue 329-664 and to trpl amino acid residues 672-1124.