[Expression unit in the region of replication initiation in the streptococcal plasmid pSM19035]

Several sequences, resembling vegetative promoters and ribosome-binding sites of Bacilli were found in the primary structure of the replication region of Streptococci plasmid pSM19035. Promoterless alpha-amylase gene of Bac. amyloliquefaciens and lambda cI857 gene, supplied with BamHI site upstream of the initiator ATG-codon, were used for functional characterization of the structures. As a result, Bac. subtilis synthesized alpha-amylase up to 0.5 g/l, and lambda-repressor up to 3% of the intracellular water-soluble protein. The repressor, synthesized in Bac. subtilis, regulates lambda PR promoter in the cells. Plasmid pCB22 is constructed for the convenience of usage of the found expression unit, called EU19035. The plasmid has BamHI and BgIII sites on different distances from the ribosome-binding site.