Question

How do you suppose bacteria stop their restriction enzymes from

digesting their own DNA?

Answer 1

Bacteria have restriction enzymes which are also called restriction endonucleases, which cut double stranded DNA at specific points into fragments. Remarkably, restriction enzymes don’t cleave their own DNA. And there are two specific reasons behind the situation.

• Recognition sequence normally does not exist in the bacterial DNA.
• If the recognition sequences exist but the enzyme is methylation specific. Bacteria prevent their own DNA from cutting down by restriction enzyme by methylation of the restriction sites. Methylation of DNA is a very accustomed way to modify DNA function and bacterial DNA is highly methylated. This overall process is called as restriction modification system.