Molecular cloning of a major cell wall protein gene from protein-producing Bacillus brevis 47 and its expression in Escherichia coli and Bacillus subtilis.

Bacillus brevis 47 contains two major cell wall proteins. Each protein forms a hexagonal array in the cell wall. A 4.8-kilobase HindIII fragment of B. brevis 47 DNA cloned into Escherichia coli with pBR322 as a vector directed the synthesis of polypeptides cross-reactive with antibody to the middle wall protein. A 700-base-pair BamHI-HpaI fragment was shown to be the essential region for the synthesis of immunoreactive polypeptides. Furthermore, this fragment appeared to contain the promoter activity. The 3.5-kilobase BamHI fragment covering the essential region as well as its downstream sequence was subcloned into the corresponding restriction site of pUB110 by using Bacillus subtilis as the cloning host. Both E. coli and B. subtilis carrying the cloned DNA synthesized several immunoreactive polypeptides which were mainly found in the cytoplasm. B. subtilis secreted polypeptides cross-reactive with antibody to the middle wall protein. These extracellular polypeptides were degraded upon prolonged culture.