Question

How does bacteria protect their own DNA against restriction enzymes?

Answer 1

Hint: A restriction enzyme is a protein that recognizes a particular short nucleotide sequence and only cuts the DNA at that specific site, known as the target sequence or restriction site. Bacteria protect their own DNA by manipulating the sequence of its own DNA

Complete answer:
Restriction enzymes also called restrictase perform the role of breaking down DNA molecules into small fragments at a particular site called restriction site. The bacteria produce restriction enzymes but protect their own DNA by altering their own recognition sequences, typically by attaching methyl molecules to nucleotides in the recognition sequences and then relying on the ability of the restriction enzymes to recognize and cleave only unmethylated recognition sequences. DNA methylation is a common way of modifying the function of DNA and is highly methylated by bacterial DNA. It works to render the restriction sites for the restriction enzymes unrecognizable in this situation.

Additional information:
Bacteria produce restriction enzymes. This is because a bacteriophage injects its DNA into a bacterial cell during infection. If it has restriction enzymes that can attack the DNA of the bacteriophage, the bacterium can protect itself. Restriction enzymes in the bacterial cell cleave foreign DNA, thereby preventing infecting organisms. Restriction enzymes are typically categorized into five groups, which vary in their structure and whether their DNA substrate is cut at the site of recognition, or whether the sites of recognition and cleavage are distinct from each other. Two incisions are made by restriction enzymes in order to cut DNA, once through each sugar-phosphate backbone of the double helix structure of DNA.

Note:
More than 400 restriction enzymes are isolated from the bacteria that produce them. Restriction enzymes, such as those containing genes, can be removed from bacterial cells and used in the laboratory to modify fragments of DNA, making them important tools for recombinant DNA technology or genetic engineering.