Cloning and expression of the BamHI restriction-modification system in Bacillus subtilis

Abstract The genes of the GGATCC-specific Bam HI restriction-modification system of Bacillus amyloliquefaciens H have been cloned and expressed in Bacillus subtilis MT-2. B. subtilis MT-2 carrying the recombinant plasmid (pBamHIRM22) produced about 10-fold more Bam HI restriction endonuclease and Bam HI methylase than B. amyloliquefaciens H did. B. subtilis MT-2 (pBamHIRM22) restricted unmodified phage. Restriction and modification genes were stably maintained in B. subtilis MT-2 on one plasmid and the produced Bam HI endonuclease remained stable even in the stationary phase of the culture. Bam HI endonuclease from B. subtilis MT-2 (pBamHIRM22) had the same molecular weight and N-terminal amino acid sequence as that from B. amyloliquefaciens H.