Cloning and expression in Escherichia coli of the BanI and BanIII restriction-modification systems from Bacillus aneurinolyticus

Abstract The genes coding for the GGPyPuCC-specific ( Ban I) and ATCGAT-specific ( Ban III) restriction-modification systems of Bacillus aneurinolyticus IAM1077 were cloned and expressed in Escherichia coli using pBR322 as a vector. The plasmids carrying the Ban I and Ban III restriction-modification genes were designated pBanIRM8 and pBanIIIRM12, respectively. The restriction maps of these recombinant plasmids were constructed. These two plasmids were stably maintained in E. coli HB101. However, when E. coli JM109 was used as a host, pBanIIIRM12 was efficiently propagated but pBanIRM8 was not. The HB101 cells carrying only the restriction gene of Ban III were viable, but the Ban I restriction gene carrier could not form colonies on agar plates. The growth of bacteriophage λ was strongly restricted only in the F. coli HB101 cells harboring pBanIRM8. These facts indicate that the Ban I restriction enzyme is expressed and functions more efficiently than Ban I modification enzyme in E. coli .