The genes of the 5'-GGCC specific BsuRI restriction-modification system of Bacillus subtilis have been cloned and expressed in E. coli and their nucleotide sequence has been determined. The restriction and modification genes code for polypeptides with calculated molecular weights of 66,314 and 49,642, respectively. Both enzymes are coded by the same DNA strand. The restriction gene is upstream ...

Certain type II restriction modification gene systems can kill host cells when these gene systems are eliminated from the host cells. Such ability to cause postsegregational killing of host cells is the feature of bacterial addiction modules, each of which consists of toxin and antitoxin genes. With these addiction modules, the differential stability of toxin and antitoxin molecules in cells pl...

A total of 22 type II restriction endonucleases with 18 distinct specificities have been identified in six Helicobacter pylori strains. Among these 18 specificities are three completely new endonucleases, Hpy178III, Hpy99I, and Hpy188I, that specifically cleave DNA at TCNNGA, CGWCG, and TCNGA sites, respectively. The set of endonucleases identified in each strain varies, but all have four- or f...