Plasmid-directed expression of Staphylococcus aureus beta-lactamase by Bacillus subtilis in vitro.

A plasmid carrying the Gram-positive Staphylococcus aureus PC1 beta-lactamase gene is active in directing a cell-free transcription and translation system from Bacillus subtilis. The major protein synthesized has been identified as the S. aureus beta-lactamase on the basis of peptide mapping. The protein is larger than the extracellular enzyme by about Mr = 3100. Significant in vitro translation of the beta-lactamase mRNA occurs in the absence of the initiation factor fraction as is characteristic of translation of mRNAs of Gram-positive origin. The 1250 base transcript that encodes the beta-lactamase and leader sequence has been mapped on the plasmid molecule.