Postreplicative methylation of bacterial DNA has long been known to be the molecular basis of" modification," which protects DNA against destruction by restriction endonucleases. More recently, another function of DNA methylation was found in Escherichia coli, where methy- lation is involved during DNA replication in the recogni- tion of old and newly synthesized strands. The intensive search for new restriction enzymes during the 1970s yielded an enormous arsenal of such enzymes and re- vealed the ubiquitous distribution of restriction/modifi- cation systems in the bacterial kingdom without...
Postreplicative methylation of bacterial DNA has long been known to be the molecular basis of" modification," which protects DNA against destruction b...