type IV restriction enzyme

Type IV restriction enzymes are proteins produced by bacteria that cleave DNA, specifically targeting methylated DNA. Unlike other types, they have weak sequence specificity. Restriction enzymes, in general, are crucial tools in molecular biology and genetic engineering, allowing scientists to cut DNA at precise locations. Bacteria use them to defend against foreign DNA, such as that from bacteriophages, by cutting it into pieces. There are four main types of restriction enzymes (I, II, III, and IV), distinguished by their structure, cleavage site, specificity, and cofactors.12